Fill - Free fillable Datenblatt 0000025 1 PDF form

Number 26

Printed in U.S.A. 90-861329--1 MARCH 1999

1999, Mercury Marine

MARINE ENGINES

SERVICE

MANUAL

GM 4 Cylinder 181 cid (3.0L)

MAIN MENU

MerCruiser # 26 GM 4 Cylinder 181 cid (3.0L)

90-861329--1

MerCruiser # 26 GM 4 Cylinder 181 cid (3.0L)

90-861329--1

90-861329--1 MARCH 1999 Page i

Notice

Throughout this publication, “Dangers”, “Warnings” and “Cautions” (accompanied by the In-

ternational HAZARD Symbol

) are used to alert the mechanic to special instructions con-

cerning a particular service or operation that may be hazardous if performed incorrectly or

carelessly. OBSERVE THEM CAREFULLY!

These “Safety Alerts” alone cannot eliminate the hazards that they signal. Strict compliance

to these special instructions when performing the service, plus “Common Sense” operation,

are major accident prevention measures.

DANGER

DANGER - Immediate hazards which WILL result in severe personal injury or death.

WARNING

WARNING - Hazards or unsafe practices which COULD result in severe personal in-

jury or death.

CAUTION

Hazards or unsafe practices which could result in minor personal injury or product

or property damage.

Notice to Users of This Manual

This service manual has been written and published by the Service Department of Mercury

Marine to aid our dealers’ mechanics and company service personnel when servicing the

products described herein.

It is assumed that these personnel are familiar with the servicing procedures of these prod-

ucts, or like or similar products manufactured and marketed by Mercury Marine, that they

have been trained in the recommended servicing procedures of these products which in-

cludes the use of mechanics’ common hand tools and the special Mercury Marine or recom-

mended tools from other suppliers.

We could not possibly know of and advise the service trade of all conceivable procedures

by which a service might be performed and of the possible hazards and/or results of each

method. We have not undertaken any such wide evaluation. Therefore, anyone who uses

a service procedure and/or tool, which is not recommended by the manufacturer, first must

completely satisfy himself that neither his nor the products safety will be endangered by the

service procedure selected.

All information, illustrations and specifications contained in this manual are based on the

latest product information available at the time of publication. As required, revisions to this

manual will be sent to all dealers contracted by us to sell and/or service these products.

It should be kept in mind, while working on the product, that the electrical system and ignition

system are capable of violent and damaging short circuits or severe electrical shocks. When

performing any work where electrical terminals could possibly be grounded or touched by

the mechanic, the battery cables should be disconnected at the battery.

Any time the intake or exhaust openings are exposed during service they should be covered

to protect against accidental entrance of foreign material which could enter the cylinders and

cause extensive internal damage when the engine is started.

Index

Page ii 90-861329--1 MARCH 1999

It is important to note, during any maintenance procedure replacement fasteners must have

the same measurements and strength as those removed. Numbers on the heads of the met-

ric bolts and on the surfaces of metric nuts indicate their strength. American bolts use radial

lines for this purpose, while most American nuts do not have strength markings. Mis-

matched or incorrect fasteners can result in damage or malfunction, or possibly personal

injury. Therefore, fasteners removed should be saved for reuse in the same locations when-

ever possible. Where the fasteners are not satisfactory for re-use, care should be taken to

select a replacement that matches the original.

We reserve the right to make changes to this manual without prior notification.

Refer to dealer service bulletins for other pertinent information concerning the products de-

scribed in this manual.

Engine Mechanical Components

Many of the engine mechanical components are designed for marine applications. Unlike

automotive engines, marine engines are subjected to extended periods of heavy load

and wide-open-throttle operation and, therefore, require heavy-duty components. Special

marine engine parts have design and manufacturing specifications which are required to

provide long life and dependable performance. Marine engine parts also must be able to

resist the corrosive action of salt or brackish water that will rust or corrode standard automo-

tive parts within a short period of time.

Failure to use recommended Quicksilver service replacement parts can result in poor en-

gine performance and/or durability, rapid corrosion of parts subjected to salt water and

possibly complete failure of the engine.

Use of parts other than recommended service replacement parts, will void the warranty on

those parts which are damaged as a result of the use of other than recommended replace-

ment parts.

Replacement Parts

WARNING

Electrical, ignition and fuel system components on MerCruiser Engines and Stern

Drives are designed and manufactured to comply with U.S. Coast Guard Rules

and Regulations to minimize risks of fire or explosion.

Use of replacement electrical, ignition or fuel system components, which do not

comply to these rules and regulations, could result in a fire or explosion hazard and

should be avoided.

When servicing the electrical, ignition and fuel systems, it is extremely important

that all components are properly installed and tightened. If not, any electrical or ig-

nition component opening would permit sparks to ignite fuel vapors from fuel sys-

tem leaks, if they existed.

Models Covered in This Manual

Model Serial Number Model Year

MCM 3.0L Alpha OL010042 and Above 1998 -

Index

Important Information

Removal And Installation

Engine

Electrical System

Fuel System

Cooling System

Exhaust System

Power Steering

90-861329--1 MARCH 1999 Page iii

Service Manual Outline

Section 1 - Important Information

A - General Information

B - Maintenance

C - Troubleshooting

Section 2 - Removal and Installation

A - MCM 3.0L (181 CID) - Alpha Drive

Section 3 - Engine

A - 3.0L (181 CID)

Section 4 - Electrical System

A - Starting System

B - Ignition System

C - Charging System

D - Instrumentation

E - Wiring Diagrams

Section 5 - Fuel System

A - Fuel Pump

B - MerCarb 2-Barrel

Section 6 - Cooling System

A - Seawater Cooled Models

B - Closed Cooled Models

Section 7 - Exhaust System

A - Exhaust Manifolds / Elbows

Section 8 - Power Steering

A - Power Steering

Index

Page iv 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-1

IMPORTANT INFORMATION

Section 1A - General Information

Table of Contents

Table of Contents 1A-1. . . . . . . . . . . . . . . . . . . . .

Introduction 1A-2. . . . . . . . . . . . . . . . . . . . . . . . . . .

How to Use This Manual 1A-2. . . . . . . . . . . . . . .

Page Numbering 1A-2. . . . . . . . . . . . . . . . . . .

How to Read a Parts Manual 1A-3. . . . . . . . . . .

Directional References 1A-4. . . . . . . . . . . . . . . . .

Engine Rotation 1A-4. . . . . . . . . . . . . . . . . . . . . . .

Engine Serial Number Locations 1A-5. . . . . . . .

Propeller Information 1A-5. . . . . . . . . . . . . . . . . .

Water Testing New Engines 1A-6. . . . . . . . . . . .

Boat and Engine Performance 1A-6. . . . . . . . . .

Boat Bottom 1A-6. . . . . . . . . . . . . . . . . . . . . . .

Marine Fouling 1A-8. . . . . . . . . . . . . . . . . . . . .

Weight Distribution 1A-9. . . . . . . . . . . . . . . . . .

Water in Boat 1A-9. . . . . . . . . . . . . . . . . . . . . .

Elevation and Climate 1A-9. . . . . . . . . . . . . . .

Index

GENERAL INFORMATION SERVICE MANUAL NUMBER 26

Page 1A-2 90-861329--1 MARCH 1999

Introduction

This comprehensive overhaul and repair manual is designed as a service guide for the mod-

els previously listed. It provides specific information, including procedures for disassembly,

inspection, assembly and adjustment to enable dealers and service mechanics to repair and

tune these engines.

Before attempting repairs or tune-up, it is suggested that the procedure first be read through

to gain knowledge of the methods and tools used and the cautions and warnings required

for safety.

How to Use This Manual

This manual is divided into sections which represent major components and systems.

Some sections are further divided into parts which more fully describe the component.

Sections and section parts are listed on the “Service Manual Outline” page following “V-8

Models Covered in This Manual” page.

Page Numbering

Two number groups appear at the bottom of each page. Following is an example and

description.

a-Section Number

b-Section Part

c-Page Number

d-Manual Part Number

e-Revision Number

f-Month Printed

g-Year Printed

Index

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-3

How to Read a Parts Manual

POWER STEERING PUMP ASSEMBLY

REF.

NO.

PART NO. SYM. QTY. DESCRIPTION

90507A12 1 PUMP ASSEMBLY–Power Steering

36- 95805 1 CAP

73873A1 1 PULLEY

16- 41877 1 STUD

57- 65607T 1 V-BELT

32- 806684 1 HOSE–Pressure (FITTINGS ON BOTH ENDS)

25- 89879 1 O-RING

25- 806232 1 O-RING

13- 35048 1 LOCKWASHER (3/8 in.)

61990 1 CABLE TIE

REF. NO. : Number shown next to part on exploded view

PART NO. : Mercury Part Number for ordering. If NSS (not sold separately) sometimes GM

part number will be given in description column.

QTY. : The quantity that must be ordered.

DESCRIPTION : Description of part, what parts are included with a part (all indented items

come with the main item above the indented parts), serial number information, and special

information.

Index

GENERAL INFORMATION SERVICE MANUAL NUMBER 26

Page 1A-4 90-861329--1 MARCH 1999

Directional References

Front of boat is bow; rear is stern. Starboard side is right side; port side is left side. In this

maintenance manual, all directional references are given as they appear when viewing boat

from stern looking toward bow.

72000

STARBOARD

(RIGHT)

PORT

(LEFT)

FORE or BOW

(FRONT)

AFT or STERN

(REAR)

Engine Rotation

Engine rotation is determined by observing flywheel rotation from the rear (stern end) of the

engine looking forward (toward water pump end). Propeller rotation is not necessarily the

same as engine rotation. When ordering replacement engine, short blocks or parts for

engine, be certain to check engine rotation. Do not rely on propeller rotation in determining

engine rotation.

72001

Standard Left Hand Rotation

Index

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-5

Engine Serial Number Locations

71559

a-Serial Number Plate

b-Starter Motor

Propeller Information

Refer to the “Propeller” section in appropriate MerCruiser Sterndrive Service Manual, or

order publication 90-86144, “What You Should Know About Quicksilver Propellers.”

Changing diameter, pitch or coupling of a propeller will affect engine rpm and boat perfor-

mance. The blade configuration also will affect performance. Two like propellers, same pitch

and diameter, from two different manufacturers also will perform differently.

It is the responsibility of the boat manufacturer and/or selling dealer to equip the boat with

the correct propeller to allow the engine to operate within its specified rpm range at

wide-open-throttle (W.O.T.).

Because of the many variables of boat design and operation, only testing will determine the

best propeller for the particular application.

To test for correct propeller, operate boat (with an average load onboard) at W.O.T. and

check rpm with an accurate tachometer. Engine rpm should be near top of the specified

range so that, under heavy load, engine speed will not fall below specifications.

If engine exceeds the specified rpm, an increase in pitch and/or diameter is required.

If engine is below rated rpm, a decrease in pitch and/or diameter is required.

Normally, a change of approximately 400 rpm will be achieved for each single pitch change

of a propeller.

CAUTION

If a propeller is installed that does not allow engine rpm to reach the specified

full-throttle rpm range, the engine will “labor” and will not produce full power.

Operation under this condition will cause excessive fuel consumption, engine

overheating and possible piston damage (due to detonation). On the other hand,

installation of a propeller that allows engine to run above the specified rpm limit will

cause excessive wear on internal engine parts which will lead to premature engine

failure.

Index

GENERAL INFORMATION SERVICE MANUAL NUMBER 26

Page 1A-6 90-861329--1 MARCH 1999

Water Testing New Engines

Use care during the first 20 hours of operation on new MerCruiser engines or possible

engine failure may occur. If a new engine has to be water-tested at full throttle before the

break-in period is complete, follow this procedure.

1. Start engine and run at idle rpm until normal operating temperature is reached.

2. Run boat up on plane.

3. Advance engine rpm (in 200 rpm increments) until engine reaches its maximum rated

rpm.

IMPORTANT: Do not run at maximum rpm for more than 2 minutes.

Boat and Engine Performance

Boat Bottom

For maximum speed, a boat bottom should be as flat as possible in a fore-aft direction

(longitudinally) for approximately the last 5 ft (1.5 m).

72002

a-Critical Bottom Area

Index

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-7

For best speed and minimum spray, the corner between the bottom and the transom should

be sharp.

72003

a-Bottom

b-Corner

c-Transom

The bottom is referred to as having a “hook” if it is concave in the fore-and-aft direction. A

hook causes more lift on the bottom near the transom and forces the bow to drop. This

increases wetted surface and reduces boat speed. A hook, however, aids in planing and

reduces any porpoising (rhythmical bouncing) tendency. A slight hook is often built in by the

manufacturer. A hook also can be caused by incorrect trailering or storing the boat with

support directly under the transom.

72004

a-Hook

A “rocker” is the reverse of a hook. The bottom is convex or bulged in the fore-and-aft direc-

tion. It can cause the boat to porpoise.

72005

a-Rocker

Any hook, rocker or surface roughness on the bottom, particularly in the all-important

center-aft portion will have a negative effect on speed, often several miles per hour on a fast

boat.

Index

GENERAL INFORMATION SERVICE MANUAL NUMBER 26

Page 1A-8 90-861329--1 MARCH 1999

Marine Fouling

Fouling is an unwanted build-up (usually animal-vegetable-derived) occurring on the boat’s

bottom and drive unit. Fouling adds up to drag, which reduces boat performance. In fresh

water, fouling results from dirt, vegetable matter, algae or slime, chemicals, minerals and

other pollutants. In salt water, barnacles, moss and other marine growth often produce

dramatic build-up of material quickly. Therefore, it is important to keep the hull as clean as

possible in all water conditions to maximize boat performance.

Antifouling paint, if required, may be applied to boat hull observing the following precautions.

IMPORTANT: DO NOT paint anodes or MerCathode System reference electrode and

anode, as this will render them ineffective as galvanic corrosion inhibitors.

CAUTION

Avoid corrosion damage. Do not apply antifouling paint to MerCruiser drive unit or

transom assembly.

IMPORTANT: If antifouling protection is required, Tri-Butyl-Tin-Adipate (TBTA) base

antifouling paints are recommended on MerCruiser boating applications. In areas

where Tri-Butyl-Tin-Adipate base paints are prohibited by law, copper base paints

can be used on boat hull and boat transom. Corrosion damage that results from the

improper application of antifouling paint will not be covered by the limited warranty.

Observe the following:

Avoid an electrical interconnection between the MerCruiser Product, Anodic Blocks,

or MerCathode System and the paint by allowing a minimum of 1 in. (26mm)

UNPAINTED area on transom of the boat around these items.

71176

a-Antifouling Paint

b-MINIMUM 1 inch (26 mm) Unpainted Area

Index

GENERAL INFORMATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1A-9

Weight Distribution

Weight distribution is extremely important; it affects a boat’s running angle or attitude. For

best top speed, all movable weight - cargo and passengers - should be as far aft as possible

to allow the bow to come up to a more efficient angle (3 to 5 degrees). On the negative side

of this approach is the problem that, as weight is moved aft, some boats will begin an unac-

ceptable porpoise.

Secondly, as weight is moved aft, getting on plane becomes more difficult.

Finally, the ride in choppy water becomes more uncomfortable as the weight goes aft. With

these factors in mind, each boater should seek out what weight locations best suit his/her

needs.

Weight and passenger loading placed well forward increases the “wetted area” of the boat

bottom and, in some cases, virtually destroys the good performance and handling charac-

teristics of the boat. Operation in this configuration can produce an extremely wet ride, from

wind-blown spray, and could even be unsafe in certain weather conditions or where bow

steering may occur.

Weight distribution is not confined strictly to fore and aft locations, but also applies to lateral

weight distribution. Uneven weight concentration to port or starboard of the longitudinal

centerline can produce a severe listing attitude that can adversely affect the boat’s

performance, handling ability and riding comfort. In extreme rough water conditions, the

safety of the boat and passengers may be in jeopardy.

Water in Boat

When a boat loses performance, check bilge for water. Water can add considerable weight

to the boat, thereby decreasing the performance and handling.

Make certain that all drain passages are open for complete draining.

Elevation and Climate

Elevation has a very noticeable effect on the wide-open-throttle power of an engine. Since

air (containing oxygen) gets thinner as elevation increases, the engine begins to starve for

air. Humidity, barometric pressure and temperature do have a noticeable effect on the

density of air. Heat and humidity thin the air. This phenomenon can become particularly

apparent when an engine is propped out on a cool dry day in spring and later, on a hot, humid

day in August, does not have the same performance.

Although some performance can be regained by dropping to a lower pitch propeller, the

basic problem still exists. The propeller is too large in diameter for the reduced power output.

A Quicksilver Propeller Repair Station or experienced marine dealer can determine how

much diameter to remove from a lower-pitch propeller for specific high-elevation locations.

In some cases, installing high altitude gears in the drive unit is possible and very beneficial.

Weather conditions may effect the power output of internal combustion engines. Therefore,

established horsepower ratings refer to the power that the engine will produce at its rated

rpm under a specific combination of weather conditions.

Index

GENERAL INFORMATION SERVICE MANUAL NUMBER 26

Page 1A-10 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-1

IMPORTANT INFORMATION

Section 1B - Maintenance

Table of Contents

Maintenance Schedule 1B-2. . . . . . . . . . . . . . . . .

Maintenance Intervals 1B-2. . . . . . . . . . . . . . .

Scheduled Maintenance That Can

Be Performed By Owner/Operator 1B-2. . .

Scheduled Maintenance That Should

Be Performed By A Dealer 1B-3. . . . . . . . . .

Engine and Tune-Up Specifications 1B-4. . . . . .

Fluid Capacities 1B-5. . . . . . . . . . . . . . . . . . . . . . .

Engine Rotation and Firing Order 1B-5. . . . . . . .

L.H. Rotation Front 1B-5. . . . . . . . . . . . . . . . .

20-Hour Break-In Period 1B-5. . . . . . . . . . . . . . .

After Break-in Period 1B-6. . . . . . . . . . . . . . . . . .

End of First Season Checkup 1B-6. . . . . . . . . . .

Fuel 1B-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuel Ratings 1B-6. . . . . . . . . . . . . . . . . . . . . . .

General Information 1B-6. . . . . . . . . . . . . . . . .

Gasoline / Alcohol Blends 1B-7. . . . . . . . . . . .

Effects of Gasoline / Alcohol Blends

on Marine Engines 1B-7. . . . . . . . . . . . . . . . .

Boat / Motor Storage 1B-8. . . . . . . . . . . . . . . .

Winter Storage 1B-8. . . . . . . . . . . . . . . . . . . . .

Warranty 1B-8. . . . . . . . . . . . . . . . . . . . . . . . . .

Continuing Evaluations 1B-8. . . . . . . . . . . . . .

Test For Alcohol Content In Gasoline 1B-8. .

Crankcase Oil 1B-9. . . . . . . . . . . . . . . . . . . . . . . .

Overfilled Crankcase Oil 1B-9. . . . . . . . . . . . .

Adding Crankcase Oil 1B-10. . . . . . . . . . . . . .

Checking Engine Oil Level/Filling 1B-10. . . .

Changing Oil and Filter 1B-11. . . . . . . . . . . . . . . .

Priming Engines With Oil 1B-11. . . . . . . . . . . . . .

Tools Required 1B-11. . . . . . . . . . . . . . . . . . . .

Procedure 1B-11. . . . . . . . . . . . . . . . . . . . . . . .

Power Steering System 1B-12. . . . . . . . . . . . . . .

Checking Fluid Level 1B-12. . . . . . . . . . . . . . .

Filling and Bleeding 1B-13. . . . . . . . . . . . . . . .

Closed Cooling System 1B-14. . . . . . . . . . . . . . .

Checking Coolant Level 1B-14. . . . . . . . . . . .

Coolant for Closed Cooling System 1B-14. .

Flushing System 1B-15. . . . . . . . . . . . . . . . . . .

Lubrication 1B-17. . . . . . . . . . . . . . . . . . . . . . . . . .

Throttle Cable 1B-17. . . . . . . . . . . . . . . . . . . . .

Shift Cable 1B-18. . . . . . . . . . . . . . . . . . . . . . . .

Engine Coupler / U-Joint Shaft

Splines 1B-18. . . . . . . . . . . . . . . . . . . . . . . . . .

Cold Weather or Extended Storage 1B-19. . . . .

Precautions 1B-19. . . . . . . . . . . . . . . . . . . . . . .

Power Package Layup 1B-20. . . . . . . . . . . . .

Draining Instructions 1B-21. . . . . . . . . . . . . . . . . .

Single Point Drain System 1B-21. . . . . . . . . .

Draining Seawater (Raw-Water)

Cooled Models 1B-23. . . . . . . . . . . . . . . . . . .

Draining Seawater Section of Closed

Cooled (Coolant) Models 1B-26. . . . . . . . . .

Recommissioning 1B-28. . . . . . . . . . . . . . . . . .

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-2 90-861329--1 MARCH 1999

Maintenance Schedule

Maintenance Intervals

Maintenance intervals and the tasks to be performed, as shown in this current schedule, or

as found in previously printed schedules, are generally based on an average boating

application and environment. However, individual operating habits and personal mainte-

nance preferences can have an impact on the suggested intervals. In consideration of these

factors, MerCruiser has adjusted some maintenance intervals and corresponding tasks to

be performed. In some cases, this may allow for more individual tasks to be performed in

a single visit to the servicing dealer, rather than multiple visits. Therefore, it is very important

that the boat owner and servicing dealer discuss the current Maintenance Schedule and

develop appropriate maintenance intervals to coincide with the individual operating habits,

environment and maintenance requirements.

Scheduled Maintenance That Can Be Performed By Owner/Operator

NOTE: Only perform maintenance which applies to your particular power package.

Task

Interval

Engine Crankcase Oil - Check level.

Closed Cooling Coolant - Check level.

Power Steering Fluid - Check level.

Sterndrive Unit Oil - Check level.

Battery - Check level and inspect for

damage.

Fuel Pump Sight Tube (If Equipped) - Check

that no fuel is present.

Weekly

Power Trim Pump Oil - Check level.

Anodes - Inspect for erosion.

Gear Housing Water Pickups - Check for

marine growth or debris.

Drive Belts (All) - Inspect condition and

check tension.

Every 100 hours of operation or 120 days,

whichever occurs first.

Propeller Shaft - Lubricate.

Saltwater Use: Every 50 hours of operation

or 60 days, whichever occurs first.

Power Package Exterior Surfaces - Spray

with rust preventative.

Freshwater Use: Every 100 hours of

operation or 120 days, whichever occurs

first.

Power Package Exterior Surfaces - Clean

and paint.

Once a year

Cooling System - Flush seawater section. Saltwater Use: After every use.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-3

Scheduled Maintenance That Should Be Performed By A Dealer

NOTE: Only perform maintenance which applies to your particular power package.

Task

Interval

Seawater Pickup Pump - Disassemble and

inspect.

Whenever insufficient seawater flow is

suspected (if operating temperature

exceeds normal range.)

Crankcase Oil and Filter - Change.

Ignition System - Clean and inspect

condition.

Flame Arrestor and Crankcase Ventilation

Hose - Clean and inspect.

Positive Crankcase Ventilation (PCV) Valve

(If Equipped) - Change.

Sterndrive Unit Oil - Change.

Gimbal Ring Clamping Screws - Retorque

to 50-55 lb-ft (67-74 Nm).

Rear Engine Mounts - Check, torque to

38 lb-ft (52 Nm).

Gimbal Bearing - Lubricate.

Cooling System - Clean and inspect.

Steering System - Lubricate and inspect for

loose, damaged or missing parts.

End of first boating season and thereafter,

Electrical System - Check for loose or

damaged wiring.

every 100 hours of operation or once yearly,

whichever occurs first.

Closed Cooling System Pressure Cap -

Clean, inspect and test.

Cooling System Hoses and Clamps -

Inspect for damage and deterioration.

Check clamps for tightness.

Continuity Circuit - Check components for

loose connections, broken or frayed wires.

Shift and Throttle Cable and Linkage -

Lubricate and inspect for loose, damaged or

missing parts.

Engine Exhaust System - Inspect externally

for damage, deterioration and restrictions.

Check for tightness.

Ignition System - Check timing and adjust

as needed.

Closed Cooling Coolant - Replace.

Every 5 years or 1000 hours, whichever

occurs first

Only if Extended Life 5/100 Ethylene Glycol Antifreeze/Coolant is used. If any non-compatible coolant is added

to this coolant, coolant must be changed every 2 years or 400 hours, whichever occurs first. All coolants other

than Extended Life 5/100 Ethylene Glycol Antifreeze/Coolant must be changed every 2 years or 400 hours,

whichever occurs first.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-4 90-861329--1 MARCH 1999

Engine and Tune-Up Specifications

MODEL MCM 3.0L

Propshaft Horsepower

(SAV1 Rating)

135

(114

)

Propshaft Kilowatts

(SAV1 Rating)

101

(85

)

Number of Cylinders 4

Displacement 181 cid (3.0L)

Bore/Stroke In. (mm) 4.00 X 3.60 (101.6 X 91.4)

Compression Ratio 9.25:1

Compression Pressure Minimum 100 psi (690 kPa)

Idle rpm (In Neutral)

700 rpm

Max rpm (At W.O.T.)

4400-4800 rpm

Oil Pressure (at 2000 rpm) Minimum 30 psi (207 kPa)

Fuel Pump psi (At 1000 rpm) 6-8 psi (41-55 kPa)

Minimum Oil Pressure At Idle 4 psi (28 kPa)

Electrical System 12 Volt Negative (-) Ground

Minimum Battery Requirements 375 cca / 475 mca / 90 Ah

Firing Order 1-3-4-2

Spark Plug Type

AC - MR43LTS

Champion - RS12YC

NGK - BPR6EFS

Spark Plug Gap .035 in. (0.9 mm)

Timing (At Idle)

1° BTDC

/ 1° ATDC

/ 2° ATDC

Preliminary Idle Mixture 1 1/4 Turns

Thermostat 143° F (62° C)

/ 160° F(71° C)

Power Rated in Accordance with NMMA (National Marine Manufacturers’ Association) rating procedures.

Power Rated in Accordance with SAV1 rating procedures. This rating procedure is used to certify that the en-

gine complies with “Stage 1” Bodensee and Swiss Regulations. Horsepower differences shown result from dif-

ferences in test rpm, allowable test tolerances, and/or installation of special kit components.

Measured using an accurate service tachometer with engine at normal operating temperature.

Timing must be set using a special procedure as outlined in the appropriate section of this manual. Timing can-

not be properly set using the conventional method.

A special procedure must be followed to adjust idle rpm. Consult your Authorized MerCruiser Dealer before

attempting this procedure.

Minimum recorded compression in any one cylinder should not be less than 70 percent of the highest recorded

cylinder.

Serial number break: 0L096999 and below

Serial number break: 0L097000 - 0L0340999

Serial number break: 0L341000 and above.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-5

Fluid Capacities

NOTICE

Unit Of Measurement: U.S. Quarts (Liters)

All capacities are approximate fluid measures.

MODEL MCM 181 cid / 3.0L

Crankcase (With Filter)

4 (3.8)

Seawater Cooling System

9 (8.5)

Closed Cooling System 9 (8.5)

Always use dipstick to determine exact quantity of oil or fluid required.

Seawater Cooling System capacity information is for winterization use only.

Engine Rotation and Firing Order

L.H. Rotation Front

50683

4 Cylinder - 181 cid / 3.0L Firing Order 1-3-4-2

20-Hour Break-In Period

IMPORTANT: The first 20 hours of operation is the engine break-in period. Correct

break-in is essential to obtain minimum oil consumption and maximum engine per-

formance. During this break-in period, the following rules must be observed:

• Do not operate below 1500 rpm for extended periods of time for first 10 hours. Shift into

gear as soon as possible after starting and advance throttle above 1500 rpm if condi-

tions permit safe operation.

• Do not operate at one speed consistently for extended periods.

• Do not exceed 3/4 throttle during first 10 hours. During next 10 hours, occasional

operation at full throttle is permissible (5 minutes at a time maximum).

• Avoid full throttle acceleration from IDLE speed.

• Do not operate at full throttle until engine reaches normal operating temperature.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-6 90-861329--1 MARCH 1999

After Break-in Period

To help extend the life of your MerCruiser power package, the following recommendations

should be considered;

• Use a propeller that allows the engine to operate at or near the top of the maximum rpm

range (See “Specifications” section) when at full throttle with a normal boat load.

• Operation at 3/4 throttle setting or lower is recommended. Refrain from prolonged

operation at maximum (full throttle) rpm.

End of First Season Checkup

At the end of the first season of operation, an Authorized MerCruiser Dealer should be con-

tacted to discuss and/or perform various scheduled maintenance items. If you are in an area

where the product is operated continuously (year-round operation), you should contact your

dealer at the end of the first 100 hours of operation, or once yearly, whichever occurs first.

Fuel

Fuel Ratings

CAUTION

Use of improper gasoline can damage the engine seriously. Engine damage that

results from use of improper gasoline is considered misuse of the engine and is not

covered under MerCruiser Warranty.

USA AND CANADA

Fuel having a posted pump Octane Rating of 87 (R + M) / 2 minimum. Premium gasoline

[90 (R + M) / 2] is also acceptable. DO NOT use leaded gasolines.

OUTSIDE USA AND CANADA

Fuel having a posted pump Octane Rating of 90 RON minimum. Premium gasoline (98

RON) is also acceptable. If unleaded is not available, use a major brand of leaded gasoline.

General Information

Gasolines containing alcohol, either methyl alcohol (methanol) or ethyl alcohol (ethanol)

may cause increased:

• Corrosion of metal parts.

• Deterioration of elastomer and plastic parts.

• Fuel permeation through flexible fuel lines.

• Wear and damage of internal engine parts.

• Starting and operating difficulties.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-7

Some of these adverse effects are due to the tendency of gasolines containing alcohol to

absorb moisture from the air, resulting in a phase of water and alcohol separating from the

gasoline in the fuel tank.

The adverse effects of alcohol are more severe with methyl alcohol (methanol) and are

worse with increasing alcohol content.

WARNING

Fire and Explosion Hazard: Fuel leakage from any part of the fuel system can be a

fire and explosion hazard which can cause serious bodily injury or death. Careful

periodic inspection of the entire fuel system is mandatory, particularly after

storage. All fuel system components including fuel tanks (whether plastic, metal or

fiberglass), fuel lines, primer bulbs, fittings, fuel filters and carburetors should be

inspected for leakage, softening, hardening, swelling or corrosion. Any sign of

leakage or deterioration requires replacement before further engine operation.

Because of possible adverse effects of alcohol in gasoline, it is recommended that

only alcohol-free gasoline be used where possible. If only fuel containing alcohol

is available, or if the presence of alcohol is unknown, increased inspection

frequency for leaks and abnormalities is required.

WARNING

Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into

fuel pump or fuel filter base can crack casting and/or cause a fuel leak.

IMPORTANT: When operating a MerCruiser engine on gasoline containing alcohol,

storage of gasoline in the fuel tank for long periods should be avoided. Long periods

of storage, common to boats, create unique problems. In cars, alcohol-blend fuels

normally are consumed before they can absorb enough moisture to cause trouble,

but boats often sit idle long enough for phase separation to take place. In addition,

internal corrosion may take place during storage if alcohol has washed protective oil

films from internal components.

Gasoline / Alcohol Blends

Many new motor vehicle owner manuals are warning about the potential damage from using

gasoline containing alcohol, especially METHANOL. They cite possible fuel system

damage and performance problems. These are just two of the hazards that may be caused

by alcohol. These same problems as well as the additional safety risk of fire and explosion

from fuel system leaks apply to marine inboard engines. METHANOL is more severe in its

bad effect than is ETHANOL. Alcohol is also more severe in older engines since newer

engines have materials which are more resistant to alcohol.

Effects of Gasoline / Alcohol Blends on Marine Engines

Corrosion of metals may result from use of alcohol-gasoline blends. Portable or

permanently installed fuel tanks of metal or fiberglass, fuel filters, fuel lines and float bowls

may be affected by alcohol blended fuels. Many fiberglass fuel tanks are slowly dissolved

by alcohol, leading immediately to filter and carburetor plugging and eventually to tank

failure.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-8 90-861329--1 MARCH 1999

Fuels containing alcohol will absorb moisture from the air. At first, this moisture will remain

in solution, but once the water content of the fuel has built up to about one-half of one

percent, it will separate out (phase separation), bringing the alcohol with it. This

alcohol-water mixture settles to the bottom of the fuel tank and if this mixture gets into the

engine, the engine can be seriously damaged internally, as it may wash the protective film

of oil off the bore of any cylinder that it enters. Before the engine can be restarted, it is

necessary to remove the separated alcohol and water layer, flush out the fuel system with

clean fuel and remove and dry the spark plugs.

Boat / Motor Storage

When operating a MerCruiser engine on gasoline containing alcohol, storage of gasoline

in the fuel tank for long periods of time should be avoided.

Long periods of storage, common to boats, create unique problems. In cars,

gasoline/alcohol blend fuels normally are consumed before they can absorb enough

moisture to cause trouble, but boats often sit idle long enough for phase separation to take

place. In addition, internal corrosion may take place during storage if alcohol has washed

protective oil films from internal components.

Winter Storage

If boat is to be placed in winter storage, carburetors must be run dry at idle rpm. Permanent

fuel tanks should be drained completely and Quicksilver Gasoline Stabilizer and

Conditioner added to any fuel remaining in the tank. Portable fuel tanks should be emptied

completely.

Warranty

Performance problems and fuel system or other damage resulting from the use of

gasoline-alcohol blended fuels are not the responsibility of MerCruiser and will not be

covered under our warranty.

Continuing Evaluations

The effects of gasoline with ETHANOL and METHANOL are still being evaluated by the

United States Coast Guard, the National Marine Manufacturers Association (NMMA),

Mercury Marine and other engine and boat manufacturers.

We have recommended pump posting of alcohol content of gasoline. Further we recom-

mend using gasoline known not to contain any METHANOL or ETHANOL when possible.

Test For Alcohol Content In Gasoline

The following is an acceptable and widely used field procedure for the detection of alcohol

in gasoline. Use any small transparent bottle or tube that can be capped and is, or can be,

provided with graduations or a mark at about 1/3 full. A pencil mark on a piece of adhesive

tape may be used.

PROCEDURE

1. Fill the container with water to the mark.

2. Add fuel almost to fill the container, leaving some air space, then cap the container. The

proportions of fuel to water are not critical, but there should be 2 to 3 times as much fuel

as water.

3. Shake container vigorously and allow it to sit upright for 3 to 5 minutes. If the volume

of water appears to have increased, alcohol is present. If you are not sure, there is no

need for concern. If the dividing line between water and fuel becomes cloudy, use the

middle of the cloudy band.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-9

Crankcase Oil

To help obtain optimum engine performance and to provide maximum protection, we

strongly recommend the use of Quicksilver 4-Cycle 25W-40 Marine Engine Oil. This oil is

a special blend of 25-weight and 40-weight oils for marine engines. If not available, a good

grade, straight weight, detergent automotive oil of correct viscosity, with an API service

rating of SH,CF/CF-2 may be used.

In those areas where Quicksilver 4-Cycle 25W-40 Marine Engine Oil or a recommended

straight weight oil is not available, a multi-viscosity 20W-40 or, as a second but less

preferable choice, 20W-50, with API service ratings of SH,CF/CF-2 may be used.

IMPORTANT: The use of non-detergent oils, multi-viscosity oils (other than

Quicksilver 25W-40 or a good quality 20W-40 or 20W-50), synthetic oils, low quality

oils or oils that contain solid additives are specifically not recommended.

The chart below is a guide to crankcase oil selection. The oil filter should always be changed

with the engine oil.

SAE 20W

SAE 30W

SAE 40W

32° F

° C

° F

° C

AIR TEMPERATURE

75796

Overfilled Crankcase Oil

Overfilled crankcases (oil level being too high ) can cause a fluctuation or drop in oil pressure

and rocker arm “clatter” on MerCruiser engines. The over-full condition results in the engine

crankshaft splashing and agitating the oil, causing it to foam (become aerated). The aerated

oil causes the hydraulic valve lifters to “bleed down.” This, in turn, results in rocker arm

“clatter” and loss of engine performance, due to the valves not opening properly.

Care must be taken when checking engine oil level. Oil level must be maintained between

the ADD mark and the FULL mark on the dipstick. To ensure that you are not getting a “false

reading,” make sure the following steps are done before checking the oil level.

• Boat “at rest” in the water, or

• If boat is on a trailer, raise or lower bow until the boat is setting at the approximate angle

that it would be if setting “at rest” in the water.

• Allow sufficient time for oil to drain into the crankcase if engine has just been run or oil

has just been added.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-10 90-861329--1 MARCH 1999

Adding Crankcase Oil

1. Coat sealing ring on new filter with engine oil, and install. Tighten filter securely

(following filter manufacturer’s instructions). Do not overtighten.

75809

a-Oil Filter

b-Sealing Ring

2. Fill crankcase with oil.

3. Start engine and check for leaks.

Checking Engine Oil Level/Filling

IMPORTANT: ENGINE CRANKCASE OIL MUST BE CHECKED AT INTERVALS

SPECIFIED IN “MAINTENANCE SCHEDULE” CHART. It is normal for an engine to use

a certain amount of oil in the process of lubrication and cooling of the engine. The

amount of oil consumption is greatly dependent upon engine speed, with

consumption being highest at wide-open-throttle and decreasing substantially as

engine speed is reduced.

1. Stop engine and allow boat to come to a rest.

2. Allow oil to drain back into oil pan - approximately 5 minutes.

3. Remove dipstick. Wipe clean and reinstall. Push dipstick all the way into dipstick tube.

4. Remove dipstick and note the oil level.

5. Oil level must be between the FULL and ADD marks.

6. If oil level is below ADD mark, proceed to Steps 7 and 8.

7. Remove oil filler cap from valve rocker arm cover.

8. Add required amount of oil to bring level up to, but not over, the FULL mark on dipstick.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-11

Changing Oil and Filter

1. Start engine and run until it reaches normal operating temperatures.

IMPORTANT: Change oil when engine is warm from operation, as it flows more freely,

carrying away more impurities.

2. Stop engine.

3. Remove drain plug from oil pan or from oil drain hose.

NOTE: If drain plug is not accessible because of boat construction, oil may be removed

through dipstick tube, using a Quicksilver Crankcase Oil Pump.

4. After oil has drained completely, reinstall drain plug (if removed) and tighten securely.

5. Remove and discard oil filter and its sealing ring.

Priming Engines With Oil

IMPORTANT: This applies to all power packages that have not been run within 6

months, replacement of partial engines or after rebuilding an engine.

Tools Required

71089

Remote Starter Switch (91-52024A1)

Procedure

1. Fill crankcase to proper level with recommended engine oil.

2. Remove spark plugs.

3. Leave ignition Key in “OFF” position.

4. Connect remote starter switch to large 12V terminal (RED battery cable) and small

terminal (RED/YELLOW) wire on starter motor.

a. If Remote Starter Switch is not available, disconnect PURPLE wire from ignition coil

before using key switch to crank the engine over. Tape terminal on PURPLE wire to

prevent it from touching ground.

5. Crank engine for 15 seconds, then allow starter motor to cool down for 1 minute. This

should prevent starter motor from overheating.

6. Repeat this process until a total of 45 seconds of cranking time is achieved.

7. Remove remote starter switch.

a. If key switch was used, reconnect PURPLE wire to ignition coil.

8. Install spark plugs and wires.

9. Supply cooling water to seawater pump and start motor.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-12 90-861329--1 MARCH 1999

Power Steering System

Checking Fluid Level

ENGINE WARM

1. Stop engine and position drive unit so that it is straight back.

2. Remove fill cap/dipstick from power steering pump and note fluid level.

75809

a-Fill Cap / Dipstick

b-Power Steering Pump

3. Level should be between the FULL HOT mark and ADD mark on dipstick.

72518

a-Proper Fluid Level with Engine Warm

4. If level is below ADD mark, but fluid is still visible in pump reservoir, add required amount

of Quicksilver Power Trim and Steering Fluid or automatic transmission fluid (ATF)

Dexron III through fill cap opening, to bring level up to FULL HOT mark on dipstick. DO

NOT OVERFILL.

5. If fluid is not visible in reservoir, a leak exists in the power steering system. Find cause

and correct.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-13

ENGINE COLD

1. With engine stopped, position drive unit so that it is straight back.

2. Remove fill cap/dipstick from power steering pump and note fluid level.

3. Level should be between FULL COLD mark and bottom of dipstick.

72519

a-Proper Fluid Level with Engine Cold

4. If level is below bottom of dipstick, but fluid is still visible in pump reservoir, add required

amount of Quicksilver Power Trim and Steering Fluid or automatic Dexron III

transmission fluid (ATF), through fill cap opening, to bring level up to FULL COLD mark

on dipstick. DO NOT OVERFILL.

If fluid is not visible in reservoir, a leak exists in the power steering system. Find cause and

correct.

Filling and Bleeding

IMPORTANT: Power steering system must be filled exactly as explained in the follow-

ing to be sure that all air is bled from the system. All air must be removed, or fluid in

pump may foam during operation and be discharged from pump reservoir. Foamy

fluid also may cause power steering system to become spongy, which may result in

poor boat control.

1. With engine stopped, position drive unit so that it is straight back. Remove fill

cap/dipstick from power steering pump. Add Quicksilver Power Trim and Steering Fluid

or Dexron III automatic transmission fluid (ATF), as required, to bring level up to FULL

COLD mark on dipstick.

IMPORTANT: Use only Quicksilver Power Trim and Steering Fluid or Dexron IIl auto-

matic transmission fluid (ATF), in power steering system.

2. Turn steering wheel back and forth to end of travel in each direction several times, then

recheck fluid level and add fluid, if necessary.

3. Install vented fill cap.

CAUTION

DO NOT operate engine without water being supplied to seawater pickup pump, or

pump impeller may be damaged and subsequent overheating damage to engine

may result.

4. Start engine and run at fast idle (1000-1500 rpm) until engine reaches normal operating

temperature. During this time, turn steering wheel back and forth to end of travel in each

direction several times.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-14 90-861329--1 MARCH 1999

5. Position drive unit so that it is straight back and stop engine. Remove fill cap from pump.

Allow any foam in pump reservoir to disperse, then check fluid level and add fluid, as

required, to bring level up to FULL HOT mark on dipstick. DO NOT OVERFILL. Reinstall

fill cap securely.

IMPORTANT: Drive unit must be positioned straight back and power steering fluid

must be hot to accurately check fluid level.

6. If fluid is still foamy (in Step 5), repeat Steps 4 and 5 until fluid does not foam and level

remains constant.

Closed Cooling System

Checking Coolant Level

WARNING

Allow engine to cool down before removing pressure cap. Sudden loss of pressure

could cause hot coolant to boil and discharge violently. After engine has cooled,

turn cap 1/4 turn to allow any pressure to escape slowly, then push down and turn

cap all the way off.

1. Coolant level in heat exchanger should be full (to bottom of filler neck).

IMPORTANT: When reinstalling pressure cap, be sure to tighten it until it contacts

stop on filler neck.

2. Coolant level should be between the ADD and FULL marks on coolant recovery

reservoir with the engine at normal operating temperature.

193-HR

a-Coolant Recovery Reservoir

Coolant for Closed Cooling System

CAUTION

Alcohol or Methanol base antifreeze or plain water, are not recommended for use

in fresh water section of cooling system at any time.

We recommend that the coolant section of closed cooling system be filled with Extended

Life 5/100 Ethylene Glycol Antifreeze/Coolant. In areas where the possibility of freezing

does not exist, it is permissible to use a solution of rust inhibitor and water (mixed to

manufacturer’s recommendations).

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-15

Flushing System

If engine is operated in salty, polluted, or mineral-laden water, flush cooling system (prefer-

ably after each use) to reduce corrosion and prevent the accumulation of deposits in the

system. Thoroughly flush cooling system prior to storage.

BOAT OUT OF WATER

WARNING

When flushing cooling system with boat out of the water, be certain that area in

vicinity of propeller is clear and that no person is standing nearby. As a

precautionary measure, it is recommended that propeller be removed.

CAUTION

To prevent engine or sterndrive unit damage DO NOT run engine or drive unit with-

out water being supplied to water intake openings on gear housing, and to seawater

pickup pump if equipped.

1. Connect flushing attachment as follows:

NOTE: If flushing cooling system with boat in water, raise drive unit to trailer position and

install flushing attachment. Lower drive unit to full IN/DOWN position.

a. Install Quicksilver Flushing Attachment (or equivalent) over water intake openings

in gear housing.

b. Connect hose between flushing attachment and water tap.

72012

a-Quicksilver Flushing Attachment

b-Water Hose

CAUTION

If cooling system is to be flushed with boat in the water, seacock (if equipped) must

be closed, or water inlet hose must be disconnected and plugged to prevent water

from flowing into boat.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-16 90-861329--1 MARCH 1999

2. Partially open water tap(s) (approximately 1/2 maximum capacity) and allow drive unit

and cooling system to fill completely. Do not use full tap water pressure.

72672

a-Quicksilver Flushing Attachment

b-Water To Drive Unit

NOTE: Drive unit is full when water is discharged out of drive unit, and/or seawater section

of closed cooled system is full when water is discharged through propeller.

CAUTION

Do not run engine above 1500 rpm when flushing. Suction created by seawater pick-

up pump may collapse flushing hose, causing engine to overheat.

3. Place remote control lever in NEUTRAL position and start the engine.

CAUTION

Watch temperature gauge at dash to ensure the engine does not overheat.

4. Operate engine at idle speed in NEUTRAL gear for 10 minutes or until discharge water

is clear, then stop engine.

5. Shut off water tap(s).

6. Remove hose and flushing attachment from drive unit.

BOAT IN WATER

NOTE: If flushing cooling system with boat in water, raise drive unit to trailer position, to

remove flushing attachment. Lower drive unit to full IN/DOWN position after completion.

1. Raise drive unit to full UP (trailer) position.

2. Install flushing attachment over water pickup holes in gear housing as shown.

3. Attach a hose between the flushing attachment and a water tap.

4. Lower drive unit to full IN/DOWN position.

5. Partially open water tap (approximately 1/2 maximum capacity). Do Not use full water

pressure.

6. Place remote control in neutral, idle speed position, and start engine.

7. Operate engine at idle speed in neutral for 10 minutes, the stop engine.

8. Shut off water tap.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-17

9. Raise drive unit to full UP position.

10. Remove hose and flushing attachment.

CAUTION

If boat is in the water, seacock (water inlet valve), if equipped, must remain closed

until engine is to be restarted to prevent water from flowing back into cooling

system and/or boat. If boat is not fitted with a seacock, water inlet hose must be

disconnected and plugged to prevent water from flowing back into cooling system

and/or boat. As a precautionary measure, attach a tag to the ignition switch or

steering wheel of the boat with the warning that the seacock must be opened or the

water inlet hose reconnected prior to starting engine.

a. If equipped with seacock: Observing precaution above, open seacock.

b. If NOT equipped with seacock: Observing precaution above, remove plug from

seawater inlet hose and reconnect seawater inlet hose. Tighten hose clamps

securely.

Lubrication

Lubricate pivot points with SAE 30W motor oil and cable guide contact surfaces with

Quicksilver 2-4-C Marine Lubricant with Teflon.

Throttle Cable

75811

a-Pivot Points

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-18 90-861329--1 MARCH 1999

Shift Cable

75811

a-Pivot Points

b-Guide Contact Surface

Engine Coupler / U-Joint Shaft Splines

Lubricate coupler and splines with Quicksilver Engine Coupler Spline Grease

(92-816391A4).

IMPORTANT: Sterndrive unit does not have to be removed to grease coupler.

NOTE: Refer to MerCruiser Sterndrive Service Manual for sterndrive unit removal and

installation if necessary.

72017

a-Quicksilver Engine Coupler Spline Grease

b-Grease Fitting, Use If Drive Is Installed

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-19

Cold Weather or Extended Storage

Precautions

CAUTION

Sterndrive unit should be stored in full DOWN position. Universal Joint bellows may

develop a “set” if unit is stored in raised position and may fail when unit is returned

to service.

CAUTION

If Power Package will not be used for an extended period of time or will be exposed

to freezing temperatures, drain water from seawater section of cooling system. Wa-

ter MUST BE drained to prevent corrosion and freeze damage to engine.

CAUTION

If boat is to remain in water after draining, seawater inlet hose must be removed and

plugged. The plug will prevent a siphoning action that may occur, allowing seawater

to flow from the drain holes or removed hoses.

CAUTION

DO NOT operate engine without water flowing through seawater pickup pump, as

pump impeller may be damaged and subsequent overheating damage to engine or

sterndrive unit may result.

CAUTION

Seawater section of cooling system MUST BE COMPLETELY drained for winter

storage, or immediately after cold weather use, if the possibility of freezing temper-

atures exists. Failure to comply may result in trapped water causing freeze and/or

corrosion damage to engine.

IMPORTANT: Observe the following information to ensure complete draining of

cooling system:

• Engine must be as level as possible.

• A wire should be repeatedly inserted into all drain holes to ensure there are no

obstructions in passages. Remove petcock, if necessary, to insert wire complete-

ly into drain hole.

IMPORTANT: To prevent threads in manifolds, elbows and cylinder blocks from rust-

ing out during storage, reinstall plugs using Quicksilver Perfect Seal on threads.

Never leave drain plugs out during storage.

NOTE: If possible, place a container under drains and hoses to prevent water from draining

into boat.

CAUTION

If engine is equipped with Closed Cooling System, Closed Cooling section must be

kept filled with a solution of ethylene glycol antifreeze and water (mix antifreeze to

manufacturer’s recommended proportions to protect engine to lowest temperature

to which it will be exposed). DO NOT USE PROPYLENE GLYCOL antifreeze in closed

cooling section. Seawater section, however, must be drained completely.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-20 90-861329--1 MARCH 1999

CAUTION

A discharged battery can be damaged by freezing.

IMPORTANT: MerCruiser recommends that propylene glycol antifreeze (a nontoxic

and environmentally safe) antifreeze be used in seawater section of the cooling sys-

tem for cold weather or extended storage. Make sure that the propylene glycol anti-

freeze contains a rust inhibitor and is recommended for use in marine engines. Be

certain to follow the propylene glycol manufacturer’s recommendations.

Power Package Layup

CARBURETED MODELS

NOTICE

Refer to “Cold Weather or Extended Storage Precautions” in this section,

BEFORE proceeding.

1. Follow instructions “a” or “b” depending on type fuel available during layup:

a. If boat is to be placed in storage with fuel in fuel tanks that does not contain

alcohol: Fill fuel tank(s) with fresh gasoline that does not contain alcohol and a

sufficient amount of Quicksilver Gasoline Stabilizer for Marine Engines to treat the

gasoline. Follow instructions on container.

b. If boat is to be placed in storage with fuel in fuel tanks that does contain

alcohol (if fuel without alcohol is unavailable)

: Fuel tanks should be drained as

completely as possible and Quicksilver Gasoline Stabilizer for Marine Engines

added to any fuel remaining in the tank. Follow instructions on container.

IMPORTANT: If boat is to be placed in storage with fuel containing alcohol in fuel

tanks refer to “Fuel” in this SECTION 1B for additional information.

2. Replace the water separating fuel filter as outlined in SECTION 5A - Fuel Delivery

Systems, “Water Separating Fuel Filter.”

3. Supply water to the seawater pickup pump as outlined in “Flushing Cooling System.”

4. Start the engine and check for fuel leaks. If leaks exist, stop the engine immediately.

Recheck filter installation.

5. Start the engine. Operate at idle rpm until it reaches normal operating temperature and

the fuel stabilizer has been circulated. Shut off the engine.

6. Change the engine oil and filter.

7. If boat has been operated in salty, polluted or mineral-laden waters, flush cooling system

as outlined in “Flushing Cooling System.”

8. Prepare fuel system for extended storage as follows:

a. Close the fuel shut-off valve, if equipped. If no fuel shut off valve is present, a suitable

method must be employed to STOP the flow of fuel from the fuel tank to the engine

before proceeding.

b. Remove flame arrestor assembly and start engine.

c. While operating engine at fast idle (1000-1500 rpm), fog internal surfaces of induc-

tion system and combustion chambers by squirting approximately 8 ounces (227

grams) of Quicksilver Storage Seal or SAE 20W engine oil into carburetor bores.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-21

d. Squirt the remaining 2 ounces (57 g) of Storage Seal (or oil) rapidly into carburetor,

just as the engine begins to stall, due to lack of fuel. Allow engine to stop.

e. Turn ignition key to OFF position.

f. Refer to “Flushing Cooling System” and appropriately remove water supply to the

seawater pickup pump.

9. Clean flame arrestor and crankcase ventilation hoses and reinstall.

10. Drain seawater section of cooling system as outlined in “Draining Instructions.”

11. Closed Cooling System Models: Test coolant to ensure that it will protect against

freezing to the lowest temperature expected during storage.

12. Lubricate all items outlined in “Lubrication.”

13. Service batteries. Refer to manufacturer’s instructions.

14. Clean outside of engine and repaint any areas required with Quicksilver Primer and

Spray Paint. After paint has dried, spray Quicksilver Corrosion and Rust Preventive

Type II or wipe down with Quicksilver Storage Seal or SAE 20W engine oil.

15. For drive unit layup information, refer to appropriate Sterndrive Manual.

CAUTION

Sterndrive unit should be stored in full “down” position. Universal Joint bellows

may develop a “set” if unit is stored in raised position and may fail when unit is

returned to service.

Draining Instructions

Single Point Drain System

Some models are equipped with a single point drain system consisting of 2 hoses with hard-

ware and a T-handle retrieval tool (shown below). This system drains the seawater section

of the engine only.

76242

a-T-handle Retrieval Tool

b-Hoses

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-22 90-861329--1 MARCH 1999

If your engine is equipped with this device, follow this procedure:

1. Detach the hoses from the top fittings.

76243

a-Fittings

2. Lower hoses into bilge. If hoses have developed a “set,” T-handle retrieval tool can be

used to push hoses below their connection point.

76244

a-Hoses

b-Connection Points

IMPORTANT: Hoses must be lowered below their connection point on the engine in

order to drain completely.

3. If hoses do not drain, use wire to remove blockage.

4. Pull hoses back into original position after draining is complete. Reconnect to fittings.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-23

Draining Seawater (Raw-Water) Cooled Models

NOTICE

Refer to “Cold Weather or Extended Storage Precautions” in this section,

BEFORE proceeding.

1. Engine must be as level as possible to ensure complete draining of cooling system.

2. Remove drain plugs from cylinder block and manifold.

71424

a-Drain Plug (Port and Starboard)

3. Repeatedly clean out drain holes using a stiff piece of wire. Do this until entire system

is drained.

NOTE: It may be necessary to lift, bend or lower hoses to allow water to drain completely

when hoses are disconnected.

4. Remove and lower the hoses to allow them to drain.

75815

a-Inlet Hose

b-Circulating Pump Hose

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-24 90-861329--1 MARCH 1999

5. Insert a small wire (repeatedly) to make sure that vent holes and water drain holes and

passages (as shown) are unobstructed and open.

71216

70134

a-Speedometer Pitot Tube

b-Gear Housing Cavity Drain Hole

c-Trim Tab Cavity Vent Hole

d-Trim Tab Cavity Drain Passage

e-Gear Housing Water Drain Hole (One Each - Port and Starboard)

f-Gear Housing Cavity Vent Hole

6. Crank engine over SLIGHTLY, with starter motor, to purge any water trapped in seawa-

ter pickup pump. DO NOT ALLOW ENGINE TO START.

CAUTION

If boat is in the water or is to remain in the water, seacock (if equipped) must remain

closed until engine is to be restarted, to prevent water from flowing back into

cooling system. If boat is not fitted with a seacock, seawater inlet hose must remain

disconnected and plugged, to prevent water from flowing into cooling system

and/or boat. As a precautionary measure, attach a tag to the ignition switch or

steering wheel with the warning that the seacock must be opened or the seawater

inlet hose reconnected prior to starting the engine.

7. After cooling system has been drained completely, coat threads of drain plugs with

Quicksilver Perfect Seal and reinstall. Tighten drain plugs securely. Reconnect hoses

and tighten all hose clamps securely. If NOT equipped with seacock: seawater inlet

hose must remain disconnected and plugged until engine is to be restarted.

IMPORTANT: MerCruiser recommends that propylene glycol antifreeze (nontoxic

and biodegradable, which makes it friendly to lakes and rivers) be used in seawater

section of the cooling system for cold weather or extended storage. Make sure that

the propylene glycol antifreeze contains a rust inhibitor and is recommended for use

in marine engines. Be certain to follow the propylene glycol manufacturer’s recom-

mendations.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-25

8. For additional assurance against freezing and rust, remove the thermostat cover and

thermostat. Fill the engine seawater cooling system with a mixture of antifreeze and tap

water mixed to manufacturer’s recommendation to protect engine to the lowest temper-

ature to which it will be exposed during cold weather or extended storage. Using a new

gasket, reinstall thermostat and cover. Tighten cover bolts to 30 lb-ft (41 Nm).

72589

76246

a-Lifting Eye

b-Cover

c-Gasket

d-Hose

e-Thermostat

f-Fitting

g-Housing

NOTE: Hoses shown removed only to indicate flow. Do not remove hoses.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-26 90-861329--1 MARCH 1999

Draining Seawater Section of Closed Cooled (Coolant) Models

NOTICE

Refer to “Cold Weather or Extended Storage Precautions” in this section,

BEFORE proceeding.

CAUTION

If boat is in the water or is to remain in the water, seacock (if equipped) must remain

closed until engine is to be restarted to prevent contaminated water from flowing

back into cooling system. If boat is not fitted with a seacock, water inlet hose must

be left disconnected and plugged to prevent contaminated water from flowing into

cooling system and/or boat. As a precautionary measure, attach a tag to the ignition

switch or steering wheel with the warning that the seacock must be opened or the

water inlet hose reconnected prior to starting the engine.

1. Ensure engine is as level as possible to ensure complete draining of cooling system.

2. Remove drain plug from the following locations:

a. Aft (rear) drain plug from the heat exchanger.

73581

a-Heat Exchanger Drain Plug

b. Bottom of exhaust manifold.

75177

a-Exhaust Manifold Drain Plug

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-27

3. Repeatedly clean out drain holes using a stiff piece of wire. Do this until entire system

is drained.

NOTE: It may be necessary to lift or bend hoses to allow water to drain completely.

4. Make sure gear housing water vent and drain holes, speedometer pitot hole and trim

tab cavity vent and drain holes are open and unobstructed.

71216

a-Vent Holes

b-Anode Cavity Drain Holes

c-Drain Hole

d-Speedometer Pitot Hole

5. Crank engine over,slightly with starter motor to purge any water trapped in seawater

pickup pump. Do not allow engine to start.

6. After cooling system has been drained completely, install drain plugs, reconnect hoses

and tighten all hose clamps securely.

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-28 90-861329--1 MARCH 1999

Recommissioning

NOTICE

Refer to “Cold Weather or Extended Storage Precautions” in this section

BEFORE proceeding.

WARNING

To prevent possible injury or damage to equipment, do not install battery until all

maintenance has been performed on engine.

1. Check that all cooling system hoses are connected properly and hose clamps are tight.

Check that all drain plugs are installed and tightened securely.

2. Inspect drive belts.

CAUTION

When installing battery, be sure to connect NEGATIVE (–) battery cable to

NEGATIVE (–) battery terminal and POSITIVE (+) battery cable to POSITIVE (+)

battery terminal. If battery cables are reversed, electrical system damage will result.

3. Install fully-charged battery. Clean battery cable clamps and terminals and reconnect

cables (see CAUTION listed above). Tighten each cable clamp securely when

connecting.

4. Coat terminal connections with a battery terminal anti-corrosion agent.

5. Perform all maintenance tasks listed in the MAINTENANCE SCHEDULES, except

those performed during the power package lay up procedure.

6. Perform all checks in the BEFORE STARTING column of the Operation and

Maintenance Manual OPERATION CHART.

CAUTION

Refer to FLUSHING COOLING SYSTEM before starting engine.

7. Supply water to the seawater pickup pump as outlined in “Flushing Cooling System.”

8. Start engine and closely observe instrumentation to make sure that all systems are

functioning correctly.

9. Carefully inspect engine for fuel, oil, fluid, water and exhaust leaks.

10. Check steering system and shift and throttle controls for proper operation.

11. For drive unit, refer to appropriate sterndrive manual.

Index

MAINTENANCE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1B-29

THIS PAGE IS INTENTIONALLY BLANK

Index

MAINTENANCE SERVICE MANUAL NUMBER 26

Page 1B-30 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-1

IMPORTANT INFORMATION

Section 1C - Troubleshooting

Table of Contents

Precautions 1C-2. . . . . . . . . . . . . . . . . . . . . . . . . .

Used Spark Plug Analysis 1C-3. . . . . . . . . . . . . .

Spark Plug Analysis 1C-4. . . . . . . . . . . . . . . . . . .

Normal Condition 1C-4. . . . . . . . . . . . . . . . . . .

Chipped Insulator 1C-4. . . . . . . . . . . . . . . . . . .

Wet Fouling (Oil Deposits) 1C-4. . . . . . . . . . .

Cold Fouling 1C-5. . . . . . . . . . . . . . . . . . . . . . .

Overheating 1C-5. . . . . . . . . . . . . . . . . . . . . . .

High Speed Glazing 1C-5. . . . . . . . . . . . . . . . .

Scavenger Deposits 1C-6. . . . . . . . . . . . . . . .

Pre-Ignition Damage 1C-6. . . . . . . . . . . . . . . .

Reversed Coil Polarity 1C-6. . . . . . . . . . . . . . .

Splashed Deposits 1C-7. . . . . . . . . . . . . . . . . .

Mechanical Damage 1C-7. . . . . . . . . . . . . . . .

Poor Boat Performance and/or Poor

Maneuverability 1C-8. . . . . . . . . . . . . . . . . . . . . .

Improper Full Throttle Engine RPM 1C-9. . . . . .

RPM Too High 1C-9. . . . . . . . . . . . . . . . . . . . .

RPM Too Low 1C-9. . . . . . . . . . . . . . . . . . . . . .

Engine Cranks Over But Will Not Start

Or Is Hard To Start 1C-10. . . . . . . . . . . . . . . . . .

Important Information 1C-10. . . . . . . . . . . . . .

EST Ignition System Check 1C-11. . . . . . . . . . . .

Test Description 1C-11. . . . . . . . . . . . . . . . . . .

Ignition System Check 1C-12. . . . . . . . . . . . .

Engine Will Not Crank Over/Starter

Inoperative 1C-14. . . . . . . . . . . . . . . . . . . . . . . . .

Charging System Inoperative 1C-14. . . . . . . . . .

Noisy Alternator 1C-15. . . . . . . . . . . . . . . . . . . . . .

Fuel System Rich 1C-15. . . . . . . . . . . . . . . . . . . .

Fuel System Lean 1C-16. . . . . . . . . . . . . . . . . . . .

Carburetor Malfunction 1C-16. . . . . . . . . . . . . . . .

Engine Runs Poorly At Idle 1C-18. . . . . . . . . . . .

Engine Acceleration Is Poor 1C-19. . . . . . . . . . .

Engine Runs Poorly At High RPM 1C-19. . . . . .

Poor Fuel Economy 1C-20. . . . . . . . . . . . . . . . . .

Radio Noise 1C-21. . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting With Vacuum Gauge 1C-21. . .

Miscellaneous 1C-21. . . . . . . . . . . . . . . . . . . . . . .

Instrumentation Malfunction 1C-22. . . . . . . . . . .

Engine Noise 1C-22. . . . . . . . . . . . . . . . . . . . . . . .

Important Information 1C-22. . . . . . . . . . . . . .

Valve Cover Area 1C-23. . . . . . . . . . . . . . . . . .

Cylinder Area 1C-23. . . . . . . . . . . . . . . . . . . . .

Camshaft Area 1C-23. . . . . . . . . . . . . . . . . . . .

Crankshaft Area 1C-24. . . . . . . . . . . . . . . . . . .

Miscellaneous 1C-25. . . . . . . . . . . . . . . . . . . . .

Oil Pressure 1C-26. . . . . . . . . . . . . . . . . . . . . . . . .

Miscellaneous 1C-26. . . . . . . . . . . . . . . . . . . . .

Low Oil Pressure 1C-27. . . . . . . . . . . . . . . . . .

High Oil Pressure 1C-27. . . . . . . . . . . . . . . . . .

Excessive Oil Consumption 1C-28. . . . . . . . .

Water in Engine 1C-29. . . . . . . . . . . . . . . . . . . . . .

Important Information 1C-29. . . . . . . . . . . . . .

Water In Crankcase 1C-29. . . . . . . . . . . . . . . .

Water On Top Of Pistons 1C-30. . . . . . . . . . .

Engine Overheats 1C-31. . . . . . . . . . . . . . . . . . . .

Mechanical 1C-31. . . . . . . . . . . . . . . . . . . . . . .

Cooling System 1C-32. . . . . . . . . . . . . . . . . . .

Power Steering 1C-33. . . . . . . . . . . . . . . . . . . . . .

Poor, Erratic or No Assist 1C-33. . . . . . . . . . .

Noisy Pump 1C-34. . . . . . . . . . . . . . . . . . . . . . .

Fluid Leaks 1C-34. . . . . . . . . . . . . . . . . . . . . . .

Insufficient Water Flow From Alpha One

Sterndrive Unit Seawater Pickup Pump 1C-35

Index

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-2 90-861329--1 MARCH 1999

Precautions

WARNING

Always disconnect battery cables from battery BEFORE working on fuel system to

prevent fire or explosion.

WARNING

Be careful when cleaning flame arrestor and crankcase ventilation hose; gasoline

is extremely flammable and highly explosive under certain conditions. Be sure that

ignition key is OFF. DO NOT smoke or allow sources of spark or open flame in area

when cleaning flame arrestor and crankcase ventilation hose.

WARNING

Be careful when changing fuel system components; gasoline is extremely flam-

mable and highly explosive under certain conditions. Be sure that ignition key is

OFF. DO NOT smoke or allow sources of spark or flame in the area while changing

fuel filter. Wipe up any spilled fuel immediately.

WARNING

Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into

fuel pump or fuel filter base can crack casting and/or cause a fuel leak. Follow

specific procedure, given in Section 5 of this manual, for all fuel line connections.

WARNING

Make sure no fuel leaks exist before closing engine hatch.

CAUTION

DO NOT operate engine without cooling water being supplied to water pickup holes

in gear housing, or water pump impeller will be damaged and subsequent

overheating damage may result.

CAUTION

DO NOT operate engine without water being supplied to seawater pickup pump on

engine, or pump impeller may be damaged and subsequent overheating damage to

engine may result. Engine may be operated with boat out of water, if instructions

under “Running Engine with Boat Out of Water,” following, are completed.

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-3

WARNING

When running engine with boat out of water, be certain that area in vicinity of

propeller is clear and that no person is standing nearby. As a precautionary

measure, it is recommended that the propeller be removed.

CAUTION

DO NOT run engine above 1500 rpm, as suction created by seawater pickup pump

may collapse water supply hose and cause engine to overheat.

WARNING

Be sure that engine compartment is well ventilated and that no gasoline vapors are

present to prevent the possibility of a FIRE or EXPLOSION.

WARNING

DO NOT leave helm unattended while performing idle speed adjustment.

Used Spark Plug Analysis

Use the following illustrations for determining serviceability of spark plug. Spark plug

condition also can suggest a variety of possible engine malfunctions and, therefore, can

indicate needed engine repairs. When old plugs are replaced, replace entire set. Perform

plug service only on those plugs suitable for additional service, using the following

procedures:

1. Remove any oil deposits with solvent and dry plugs thoroughly.

2. Open electrode gap wide enough to permit cleaning and filing.

3. Remove combustion deposits from firing end of spark plug with a plug cleaner. Blow off

with compressed air to remove abrasives.

4. File electrode surfaces to restore clean, sharp edges. Again remove filings with com-

pressed air.

5. Reset gap to specifications by bending only side electrode with proper tool.

IMPORTANT: When working on engine, spark plug holes and carburetor throat

should be kept covered to prevent foreign objects from entering combustion

chamber.

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-4 90-861329--1 MARCH 1999

Spark Plug Analysis

Normal Condition

Few deposits are present and probably will be light tan or gray in color. This plug shows that

plug heat range is compatible with engine, and engine is electrically and mechanically in

good running condition. With proper plug servicing (clean, file and re-gap), this plug can be

reinstalled with good results.

72420

Chipped Insulator

Chipped insulator usually results from careless plug re-gapping. Under certain conditions,

severe detonation also can split insulator firing ends. Plug must be replaced.

72420

Wet Fouling (Oil Deposits)

Plug becomes shorted by excessive oil entering combustion chamber, usually in engine with

many hours of operation. Worn piston rings, cylinder walls, valve guides or valve stem seals

are causes of oil entering combustion chamber. Only engine repairs will permanently relieve

oil wet fouling.

IMPORTANT: New engines or recently overhauled engines may wet foul plugs before

normal oil control is achieved with proper break-in procedures. Such fouled plugs

may be serviced (clean, file and re-gap) and reinstalled.

72420

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-5

Cold Fouling

Dry, black deposits indicate rich fuel mixture or weak ignition. Clogged flame arrestor,

flooding carburetor, sticky choke or weak ignition components all are probable causes. If,

however, only one or two plugs in set are fouled, check for sticking valves or bad ignition

leads. After correcting cause, service (clean, file and re-gap) plugs and reinstall.

72421

Overheating

Insulator is dull white or gray and appears blistered. Electrodes are eroded and there is an

absence of deposits. Check that correct plug heat range is being used. Also check for

over-advanced ignition timing, cooling system malfunction, lean fuel/air mixtures, leaking

intake manifold or sticking valves. Replace spark plugs.

72421

High Speed Glazing

Insulator has yellowish, varnish-like color, indicating that temperatures suddenly have risen,

usually during hard, fast acceleration under heavy load. Normal deposits do not get a

chance to blow off. Instead, they melt and form a conductive coating. Replace plugs. If

condition recurs, use colder heat range plug and service plugs more frequently.

72421

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-6 90-861329--1 MARCH 1999

Scavenger Deposits

Powdery white or yellow deposits are built up on shell, insulator and electrodes. This is

normal appearance with certain branded fuels. Accumulation on ground electrodes and

shell areas may be unusually heavy, but may be easily chipped off. Plugs can be serviced

(clean, file and re-gap) and reinstalled.

72422

Pre-Ignition Damage

Pre-ignition damage is caused by excessive high temperatures. Center electrode melts

first, followed by ground electrode. Normally, insulators are white but may be dirty if plug has

been misfiring. Check for correct plug heat range, advanced ignition timing, lean fuel

mixture, incorrect fuel used, malfunctioning cooling system, leaking intake manifold or lack

of lubrication.

72422

Reversed Coil Polarity

Concave erosion of ground electrode is an indication of reversed polarity. Center electrode

will show only normal wear. Engine will misfire and idle rough. To correct, reverse primary

coil leads. Replace spark plugs.

72422

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-7

Splashed Deposits

Spotted deposits, which sometimes occur after long delayed tune-up, accumulate after a

long period of misfiring. When normal combustion temperatures are restored, upon installa-

tion of new plugs, deposits loosen from top of piston and head and are thrown against hot

insulator. Clean and service plugs and reinstall.

72423

Mechanical Damage

Mechanical damage to spark plug firing end is caused by foreign object in combustion

chamber. Because of valve overlap, small objects can travel from one cylinder to another.

Check all cylinders, intake manifold and exhaust material to prevent further damage.

72423

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-8 90-861329--1 MARCH 1999

Poor Boat Performance and/or Poor Maneuverability

Symptom Cause

A. Improper drive unit trim angle

B. Improper weight distribution

C. Boat is underpowered

Bow too low

D. Permanent or power hook in boat

bottom

E. False bottom full of water

F. Improperly adjusted trim tabs (after

planes)

G. Dirty boat bottom (marine growth)

A. Improper drive unit trim angle

B. Propeller pitch too great

C. Dirty boat bottom (marine growth)

D. Poor running engine

Bow too high

E. Improper weight distribution

F. Rocker in boat bottom

G. False bottom full of water

H. Improperly adjusted trim tabs (after

planes)

A. Drive unit installed too high on transom

B. Dirty or rough boat bottom

C. Damaged propeller; pitch too small; di-

ameter too small

Propeller ventilating

D. Keel located too close to propeller or

too deep in the water

E. Water pickup or through hull fittings lo-

cated too close to propeller

F. Hook in boat bottom

G. Propeller plugged up with weeds

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-9

Improper Full Throttle Engine RPM

RPM Too High

Cause Special Information

Propeller

Damaged; pitch too low; diameter too

small; propeller hub slipping.

Boat

Water pickup or through hull fittings

mounted too close to propeller

(ventilation); keel located too close to

propeller and/or too deep in the water

(ventilation). Drive installed too high on

transom; wrong gear ratio.

Operation Unit trimmed out too far.

Engine coupler slipping

RPM Too Low

Cause Special Information

Propeller

Damaged; pitch too great; diameter too

great.

Boat

Dirty or damaged bottom; permanent or

power hook in bottom; false bottom full of

water. Drive installed too low on transom;

wrong gear ratio.

Operation Unit trimmed in too far.

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-10 90-861329--1 MARCH 1999

Engine Cranks Over But Will Not Start Or Is Hard To Start

Important Information

1. First, determine which engine system is causing the problem. To make an engine run,

basic components fuel, spark (ignition), and compression are required. If all three

components are present, the engine should run. If any one of the three are missing,

weak, or arriving at the wrong time the engine will not run.

2. Determine if there is fuel present by looking down the carburetor venturi while actuating

throttle. There should be a stream of fuel coming out of the accelerator pump nozzles

if the carburetor has fuel.

3. Check ignition system operation. Remove coil wire from tower on distributor cap. Hold

coil wire near ground and check for spark while cranking engine over. Repeat procedure

with spark plug wires. If there is spark at the spark plug wires, remove the spark plugs

and make sure they are correct type and heat range, and not fouled or burned.

4. Run a compression check on engine to make sure the engine is mechanically sound.

BRE

+ C

PNK

PUR

GRY

BRN

WHT

WHT/GRN

(+) (“C”)

PUR GRY

71572

a-Ignition Coil Connector

b-Pick-Up Coil

c-Distributor 3 Terminal Connector

d-Distributor HEI Module

e-Filter

f-Ignition Coil

g-To Distributor Cap

h-Primary

i-Secondary

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-11

EST Ignition System Check

Test Description

Numbers below refer to circled numbers on the diagnostic chart.

1. Two wires are checked, to ensure that an open is not present in a spark plug wire.

a. If spark occurs with EST connector disconnected, pick-up coil output is too low for

EST operation.

2. A spark indicates the problem must be the distributor cap or rotor.

3. Normally, there should be battery voltage at the “C” and “+” terminals. Low voltage would

indicate an open or a high resistance circuit from the distributor to the coil or ignition

switch. If “C” terminal voltage was low, but “+” terminal voltage is 10 volts or more, circuit

from “C” terminal to ignition coil or ignition coil primary winding is open.

4. Checks for a shorted module or grounded circuit from the ignition coil to the module. The

distributor module should be turned “OFF,” so normal voltage should be about 12 volts.

If the module is turned “ON,” the voltage would be low, but above 1 volt. This could cause

the ignition coil to fail from excessive heat. With an open ignition coil primary winding,

a small amount of voltage will leak through the module from the “BAT” to the “TACH”

terminal.

5. Applying a voltage (1.5 to 8 volts) to module terminal “P” should turn the module “ON”

and the “tach” terminal voltage should drop to about 7-9 volts. This test will determine

whether the module or coil is faulty or if the pick-up coil is not generating the proper

signal to turn the module “ON.” This test can be performed by using a DC battery with

a rating of 1.5 to 8 volts. The use of the test light is mainly to allow the “P” terminal to

be probed more easily. Some digital multi-meters can also be used to trigger the module

by selecting ohms, usually the diode position. In this position the meter may have a

voltage across its terminals which can be used to trigger the module. The voltage in the

ohm’s position can be checked by using a second meter or by checking the

manufacturer’s specification of the tool being used.

6. This should turn “OFF” the module and cause a spark. If no spark occurs, the fault is

most likely in the ignition coil because most module problems would have been found

before this point in the procedure. A module tester could determine which is at fault.

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-12 90-861329--1 MARCH 1999

Ignition System Check(1 of 2)

SPARK

CHECK FUEL, SPARK PLUGS, ETC.

SEE “TROUBLESHOOTING.”

• DISCONNECT 4 TERMINAL CONNECTOR

ON DISTRIBUTOR AND CHECK FOR

SPARK.

• IF A TACHOMETER IS CONNECTED TO THE TACH TERMINAL, DISCONNECT IT

BEFORE PROCEEDING WITH THE TEST.

• CHECK SPARK AT PLUG WIRE USING AN INDUCTIVE PICKUP TIMING LIGHT

WHILE CRANKING. A FLASHING LIGHT INDICATES SPARK. (IF NO SPARK ON FIRST

WIRE, CHECK SECOND WIRE.) A FEW SPARKS AND THEN NOTHING

IS CONSIDERED NO SPARK.

NO SPARK

• CHECK FOR SPARK AT COIL WIRE WITH TIMING

LIGHT WHILE CRANKING. (LEAVE TIMING LIGHT

CONNECTED TO COIL WIRE FOR STEPS 3-6).

NO SPARK

• DISCONNECT DISTRIBUTOR 2 TERMINAL “C/+”

CONNECTOR.

• IGNITION SWITCH “ON,” ENGINE STOPPED.

• CHECK VOLTS AT “+” AND “C” TERMINALS OF

DISTRIBUTOR HARNESS CONNECTION.

• RECONNECT DISTRIBUTOR 2

TERMINAL CONNECTOR.

• WITH IGNITION “ON,” CHECK VOLTAGE

FROM TACH. TERMINAL TO GROUND

BOTH TERMINALS 10

VOLTS OR MORE

CHECK FOR OPEN OR

GROUND IN CKT. FROM

“C” TERMINAL TO IGNI-

TION COIL. IF CKT IS OK,

FAULT IS IGNITION COIL

OR CONNECTION.

UNDER 10 VOLTS

“C”TERMINAL ONLY

REPAIR OPEN

TACH. LEAD OR

CONNECTION AND

REPEAT TEST #4.

• CONNECT TEST LIGHT FROM TACH.

TERMINAL TO GROUND.

• CRANK ENGINE AND OBSERVE

LIGHT.

OVER 10 VOLTS

REPLACE MODULE AND

CHECK FOR SPARK

FROM COIL AS IN STEP 6.

UNDER 1 VOLT

1 TO 10 VOLTS

REPLACE

IGNITION

COIL.

SPARK

SYSTEM

NO SPARK

SPARK

REPAIR WIRE FROM MOD-

ULE “+” TERMINAL TO “B”

TERMINAL OF BLACK

IGNITION COIL CONNEC-

TOR OR PRIMARY CKT. TO

IGNITION SWITCH.

BOTH TERMINALS

UNDER 10 VOLTS

CHART CONTINUED

ON NEXT PAGE

INSPECT CAP FOR WATER,

CRACKS, ETC. IF OK,

REPLACE ROTOR.

SPARK

REPLACE MAGNETIC

SHAFT ASSEMBLY.

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-13

Ignition System Check (2 of 2)

REPLACE IGNITION COIL AND

RECHECK FOR SPARK WITH

TIMING LIGHT. IF STILL NO

SPARK, REINSTALL ORIGINAL

COIL AND REPLACE

DISTRIBUTOR MODULE.

LIGHT ON

STEADY

LIGHT

BLINKS

NO DROP IN VOLTAGE

CHECK MODULE GROUND.

IF OK, REPLACE MODULE.

• CHECK FOR SPARK FROM COIL WIRE

WITH TIMING LIGHT AS TEST LIGHT IS

REMOVED FROM MODULE TERMINAL

VOLTAGE DROPS

SPARK

• REPLACE IGNITION COIL

AND REPEAT STEP 5.

NO SPARK

• IS ROTATING POLE

PIECE STILL MAGNETIZED?

SYSTEM OKIGNITION COIL REMOVED IS OK,

REINSTALL COIL AND CHECK

COIL WIRE FROM DIST. CAP. IF

OK, REPLACE DISTRIBUTOR

MODULE.

REPLACE POLE

PIECE AND

SHAFT ASSEMBLY.

YES

CHECK PICK-UP COIL OR

CONNECTIONS (COIL

RESISTANCE SHOULD BE

500-1500 OHMS AND

NOT GROUNDED.)

Fig. 1

TEST LIGHT

TO DC

POWER

SUPPLY

(1.5 to 8 V)

NO SPARK

SPARK

CHART CONTINUED

FROM PREVIOUS

PAGE

• DISCONNECT DISTRIBUTOR 4 TERMINAL CONNECTOR.

• REMOVE DISTRIBUTOR CAP.

• DISCONNECT PICK-UP COIL CONNECTOR FROM MODULE.

• CONNECT VOLTMETER FROM TACH. TERMINAL TO GROUND.

• IGNITION “ON.”

• INSULATE A TEST LIGHT PROBE TO 1/4, FROM TIP AND

NOTE VOLTAGE, AS TEST LIGHT IS MOMENTARILY CON-

NECTED FROM A VOLTAGE SOURCE (1.5 TO 8 V) TO MODULE

TERMINAL “P” (CHART 1 OF 2 PAGE 11).

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-14 90-861329--1 MARCH 1999

Engine Will Not Crank Over/Starter Inoperative

Cause Special Information

Remote control lever not in neutral

position

Battery charge low; damaged wiring; loose

electrical connections

Circuit breaker tripped

Blown fuse

Ignition switch

Slave solenoid

Faulty neutral start safety switch Open circuit

Starter solenoid

Starter motor

Mechanical engine malfunction

Charging System Inoperative

Cause Special Information

Loose or broken drive belt

Engine rpm too low on initial start Rev engine to 1500 rpm

Loose or corroded electrical connections

Faulty battery gauge Best way to test is to replace gauge

Battery will not accept charge Low electrolyte or failed battery

Faulty alternator or regulator

Refer to SECTION 4C for complete

“Charging System” diagnosis procedures

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-15

Noisy Alternator

Cause Special Information

Loose mounting bolts

Drive belt Worn, frayed or loose belt

Loose drive pulley

Worn or dirty bearings

Faulty diode trio or stator

Fuel System Rich

Cause Special Information

Warm engine carburetor percolation

Fuel boils out of float bowl when shut off

and warm. Floods intake manifold.

Clogged flame arrestor

Automatic choke not opening

Float adjustment

Float leaks or is saturated with fuel

Needle and seat leaking

Carburetor gaskets leaking

Excessive fuel pump pressure Unseats needle and seat

Cracked or porous carburetor body

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-16 90-861329--1 MARCH 1999

Fuel System Lean

Cause Special Information

Empty fuel tank

Fuel shut-off valve closed (if equipped)

Vapor lock Engine will not start after warm engine

shut down

Automatic choke Stuck open, wrong adjustment

Fuel tank vent plugged

Engine will start initially. After a short time

of running, engine will stall and will not

restart for a period of time. Can verify it is

a vent problem by running engine with

filler cap loose. Fill cap will act as a vent.

Air leak on suction side of fuel system

Sucks air into fuel system reducing fuel

volume

Plugged or pinched fuel line

Fuel pump Low pump pressure

Carburetor Malfunction

Symptoms Cause

A. Needle and seat

B. Float adjustment

C. Saturated float

Flooding

D. Gaskets leaking

E. Cracked fuel bowl

F. Fuel percolation

G. Automatic choke

A. Idle rpm too low

B. Idle mixture screws

C. Idle passages dirty

Rough idle

D. Throttle valves not closing

E. Engine flooding

F. Vacuum leak

G. Throttle body heat passages plugged

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-17

Carburetor Malfunction (continued)

A. Accelerator pump

B. Leaking gaskets

C. Automatic choke

D. Power piston or power valve

Hesitation or acceleration flatness

E. Throttle valves

F. Throttle body heat passages plugged

G. Main metering jets

H. Float adjustment

I. Secondary air valve wind-up

A. Main metering jets

B. Leaking gaskets

C. Float adjustment

Engine surges

D. Saturated float

E. Power piston or valve

F. Throttle valves

A. Power piston or valve

B. Float adjustment

Low top speed or lack of power

C. Main metering jets

D. Leaking gaskets

A. Idle rpm too low

B. Idle mixture screws

Poor cold engine operation

C. Throttle valves

D. Automatic choke

E. Engine flooding

A. Idle rpm too low

B. Idle mixture screws

C. Engine flooding

Engine stalls

D. Automatic choke

E. Dirt in carburetor

F. Accelerator pump

G. Leaking gaskets

Hard starting Refer to “Engine Starts Hard”

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-18 90-861329--1 MARCH 1999

Engine Runs Poorly At Idle

Cause Special Information

Clogged flame arrestor

Improper idle fuel mixture adjustment

Problem in ignition system causing the

engine to run rough

Idle mixture screw adjusted incorrectly

Engine floods at idle

Bad needle and seat

Engine floods at idle

Incorrect float level drop

If carburetor (2 barrel only) has a solid

needle, replace with a spring loaded

needle

Moisture on ignition components Cap or spark plug wires arcing

Water in fuel

Low grade or stale fuel

Incorrect ignition timing

Automatic choke

Spark plugs Fouled, burned, cracked porcelain

Spark plug wires Insulation breakdown, wires broken

Defective coil

Cracked or dirty distributor cap

Incorrect float level

Dirty carburetor

Vacuum leak Leak at manifold or carburetor base

Incorrect fuel pump pressure

Too low - can’t supply the carburetor

Too high - unseats the needle and seat

Low compression Also check for blown head gasket

Loose or worn distributor Timing changes

Water leaking into cylinders

Head gasket, exhaust manifold, cracked

head or valve seat

Loose or broken engine mounts

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-19

Engine Acceleration Is Poor

Cause Special Information

Also refer to “Poor Boat Performance”

Idle mixture screws

Incorrect ignition timing

Incorrect distributor or amplifier advance

curve

Refer to SECTION 4B

Accelerator pump

Check for stream of raw fuel from

accelerator pump discharge nozzle, when

opening throttle with engine shut off

Cracked or dirty distributor cap or rotor

Vacuum leak Intake manifold or carburetor base

Spark plugs

Fouled, burned; wrong heat range;

cracked porcelain

Float adjustment

Dirty carburetor

Low compression

Engine Runs Poorly At High RPM

Cause Special Information

Also refer to “Poor Boat Performance”

Crankcase overfilled with oil

Check oil level with boat at rest in the

water.

Anti-siphon valve (if equipped) Restricting fuel supply

Plugged fuel tank vent

Fuel supply

Refer to “Carburetor Malfunctions”

(See “Table of Contents”)

Ignition timing

Low grade of fuel or water in the fuel

Spark plugs

Fouled, burned, cracked porcelain,

incorrect heat range

Spark plug wires Poor insulation, broken wires

Distributor cap or rotor Dirty or cracked

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-20 90-861329--1 MARCH 1999

Engine Runs Poorly At High RPM (continued)

Cause Special Information

Coil

Distributor Excessive play in shaft

Engine overheating Refer to “Engine Overheats”

Low compression Worn valves, rings, cylinders, etc.

Restricted exhaust

Poor Fuel Economy

Cause Special Information

Fuel leaks

Operator habits

Prolonged idling; slow acceleration; failure

to cut back on throttle once boat is on

plane; boat overloaded; uneven weight

distribution

Engine laboring

Bent, damaged or wrong propeller. Water

test boat for proper operating rpm at wide

open throttle

Clogged flame arrestor

Engine compartment sealed too tight Not enough air for engine to run properly

Boat bottom Dirty (marine growth), hook, rocker

Carburetor

Idle mixture settings, accelerator pump

adjustments, linkage binding, choke

adjustment, carburetor flooding over, main

fuel jets

Improper fuel

Crankcase ventilation system not working

Engine needs tune-up

Engine running too cold or too hot

Plugged or restricted exhaust

Engine Low compression

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-21

Radio Noise

Cause Special Information

A popping noise that will increase with

engine rpm. Noise will stop as soon as

engine is turned off.

Ignition System - wrong spark plugs;

cracked distributor cap; cracked coil tower;

leaking spark plug wires; moisture on

ignition components

High pitched whine in the radio

Alternator - poor brush contact on the slip

rings

A hissing or crackling noise when

instruments are jarred with ignition on

Instrumentation - loose connections or

antennae wire routed too close to

instruments

Varying unexplained noises

Accessories - bilge pump, bilge blower;

fish finder; depth locator; cabin heater

motor, etc. Disconnect one at a time until

noise disappears.

Troubleshooting With Vacuum Gauge

Reading Cause

Steady reading between 15-21 inches at

idle rpm

Normal

Extremely low reading, but steady at idle

rpm

Vacuum leak; incorrect timing;

underpowered boat; faulty boat bottom

Fluctuates between high and low at idle

rpm

Blown head gasket between two adjacent

cylinders

Fluctuates 4 or 5 inches very slowly at idle

rpm

Carburetor needs adjustment; spark plug

gap too narrow; valves are sticking

Fluctuates rapidly at idle, steadies as rpm

is increased

Valve guides are worn

Continuously fluctuates between low and

normal reading at regular intervals at idle

rpm

Burned or leaking valve

Miscellaneous

Cause Special Information

Low grade or stale fuel

Water in fuel

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-22 90-861329--1 MARCH 1999

Instrumentation Malfunction

Cause Special Information

Faulty wiring, loose or corroded terminals

Faulty key switch Test, as outlined in SECTION 4D

Faulty gauge Test, as outlined in SECTION 4D

Faulty sender Test, As outlined in SECTION 4D

Engine Noise

Important Information

No definite rule or test will positively determine source of engine noise. Use the following

information only as a general guide to engine noise diagnosis.

1. Use a timing light to determine if noise is timed with engine speed or one-half engine

speed. Noises timed with engine speed are related to crankshaft, rods, pistons, piston

pins and flywheel. Noises timed to one-half engine speed are valve train related.

2. The use of a stethoscope can aid in locating a noise source. Because noise will travel

to other metal parts not involved in the problem, caution must be exercised.

3. If you believe noise is confined to one particular cylinder, ground spark plug leads one

at a time. If noise lessens noticeably or disappears, it is isolated to that particular cylin-

der.

4. Try to isolate the noise to location in engine: front to back, top to bottom. This can help

determine what components are at fault.

5. Sometimes noises can be caused by moving parts coming in contact with other compo-

nents. Examples are: flywheel or coupler; exhaust flappers rattling against exhaust pipe;

crankshaft striking (pan, pan baffle, or dipstick tube); rocker arm striking valve cover;

and loose flywheel cover. In many cases if this is found to be the problem, a complete

engine teardown is not necessary.

6. When noise is isolated to a certain area and component, removal and inspection will be

required. Refer to proper sections of service manual for information required for service.

7. If noise cannot be distinguished between engine and drive unit, remove drive from boat.

Run a water supply directly to engine. Run engine without the drive to determine if noise

is still there.

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-23

Valve Cover Area

Location Possible Causes

A. Rocker arm striking valve cover

Valve cover area, timed to one-half engine

B. Rocker arm out of adjustment

speed, noise could be confined to one

C. Worn rocker arm

cylinder or may be found in any multitude

of cylinders

D. Bent push rod

E. Collapsed filter

Cylinder Area

Location Possible Causes

A. Sticking valve

B. Carbon build-up

C. Connecting rod installed wrong

Cylinder area, may be confined to one

D. Bent connecting rod

cylinder or found in more than one

cylinder, timed to engine speed

E. Piston

cylinder, timed to engine speed

F. Piston rings

G. Piston pin

H. Cylinder worn

Camshaft Area

Location Possible Causes

A. Crankshaft timing sprocket

B. Timing chain

Camshaft area, front of engine,

C. Fuel Pump

timed to one half engine speed

D. Valve Lifter

E. Cam Bearings

A. Fuel Pump

Camshaft area, center of

engine, timed to one half

B. Valve Lifter

engine speed

C. Cam bearing

A. Distributor gear

Camshaft area, rear of engine,

B. Valve lifter

timed to one half engine speed

C. Cam bearings

A. Loss of oil pressure

Camshaft area, throughout

engine, timed to one half

B. Valve lifters

engine speed

C. Cam bearings

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-24 90-861329--1 MARCH 1999

Crankshaft Area

Location Possible Causes

A. Crankshaft timing sprocket

Crankshaft area, front of engine, timed to

B. Timing chain

Crankshaft area, front of engine, timed to

engine speed

C. Main bearing

D. Rod bearing

A. Crankshaft striking pan or pan baffle

Crankshaft area, center of engine, timed

B. Main bearing

to engine speed

C. Rod bearing

A. Loose flywheel cover

B. Loose coupler

Crankshaft area, rear of engine, timed to

C. Loose flywheel

engine speed

D. Main bearing

E. Rod bearing

A. Loss of oil pressure

Crankshaft area, throughout engine, timed

B. Main bearings

to engine speed

C. Rod bearings

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-25

Miscellaneous

Location / Noise Possible Causes

A. Advanced timing

B. Low octane fuel

Engine spark knock

C. Engine running hot

D. Carbon deposits in engine

A. Wrong ignition timing

B. Carburetor set too lean

C. Faulty accelerator pump

Popping through carburetor

D. Vacuum leak

E. Valve adjustment

F. Valve timing

G. Burned or stuck valve

A. Vacuum leak

B. Leaking exhaust (manifolds or pipes)

Hissing

C. Loose cylinder heads

D. Blown head gasket

A. Vacuum leak

Whistle

B. Dry or tight bearing in an accessory

A. Leaking high tension lead

Sparks jumping

B. Cracked coil tower

C. Cracked distributor cap

A. Drive belt slipping

Squeaks or squeals

B. Dry or tight bearing in an accessory

C. Parts rubbing together

Rattling in exhaust pipe area A. Exhaust shutters

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-26 90-861329--1 MARCH 1999

Oil Pressure

Miscellaneous

Problem Special Information

Measuring oil pressure

Use a good automotive oil pressure test

gauge. Do not rely on the oil pressure

gauge in the boat.

Check engine oil level with boat at rest in

the water

Oil level should be between the ADD and

FULL marks

Oil level in crankcase above FULL mark

May cause loss of engine rpm, oil

pressure gauge fluctuation, drop in oil

pressure, and hydraulic valve lifter noise

at high rpm

Oil level in crankcase below ADD mark

Low oil pressure; oil pressure gauge

fluctuation; internal engine noise and/or

damage

Change in oil pressure

This may be a normal condition. Oil

pressure may read high in the cooler times

of the day, and when engine is not up to

operating temperature. As the air

temperature warms up and engine is

running at normal opening temperature, it

is normal for oil pressure to drop.

Low engine oil pressure at idle

With modern engines and engine oils, low

oil pressure readings at idle do not

necessarily mean there is a problem. If

valve lifters do not “clatter” (at idle), there

is a sufficient volume of oil to lubricate all

internal moving parts properly. The reason

for the drop in oil pressure is that engine

heat causes an expansion of the internal

tolerances in the engine and, also, the oil

will thin out somewhat from heat.

Low engine oil pressure at idle after

running at a high rpm

Refer to preceding items

Boats with dual engines

It is not uncommon to see different oil

pressure readings between the two

engines, as long as both engines fall

within specifications. Differences in oil

pressure can be attributed to differences

in engine tolerances, gauges, wiring,

senders, etc.

Boats with dual stations Refer to preceding

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-27

Low Oil Pressure

Cause Special Information

Low oil level in crankcase

Defective oil pressure gauge and/or

sender

Verify with an automotive test gauge.

Refer to SECTION 4D for instrument

testing.

Thin or diluted oil

Oil broken down; contains water or gas;

wrong viscosity; engine running too hot or

too cold; excessive idling in cold water

(condensation)

Oil pump

Relief valve stuck open; pickup tube

restricted; worn parts in oil pump; air leak

on suction side of oil pump or pickup oil

tube

Oil leak can be internal or external

Oil passage plugs leaking, cracked or

porous cylinder block

Excessive bearing clearance

Cam bearings, main bearings, rod

bearings

High Oil Pressure

Cause Special Information

Oil too thick Wrong viscosity, oil full of sludge or tar

Defective oil pressure gauge and/or

sender

Verify with an automotive test gauge

Clogged or restricted oil passage

Oil pump relief valve stuck closed

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-28 90-861329--1 MARCH 1999

Excessive Oil Consumption

NOTE: Normal consumption is one quart of oil consumed in 5-15 hours of operation at wide-

open-throttle (especially in a new or rebuilt engine).

Cause

Special Information

Oil leaks

Clean bilge, run engine with clean white

paper on bilge floor, locate oil leak(s)

Oil too thin Oil diluted or wrong viscosity

Oil level too high

Drain holes in cylinder head plugged Oil will flood valve guides

Defective valve seals

Intake manifold gasket leaking

Worn valve stems or valve guides

Defective oil cooler (if so equipped) Crack in cooler tubes

Defective piston rings

Glazed, scuffed, worn, stuck, improperly

installed; ring grooves worn; improper

break-in; wrong end gap

Defective cylinders

Out of round, scored, tapered, glazed;

excessive piston to cylinder clearance;

cracked piston

Excessive bearing clearance

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-29

Water in Engine

Important Information

IMPORTANT: First determine location of water in engine. This information can be of

great help when trying to determine where the water came from and how it got into

the engine. The three most common problems are “water on top of pistons, water in

crankcase oil or water in crankcase oil and on top of pistons.”

The first step, after locating water, is to remove all the water from the engine by removing

all spark plugs and pumping cylinders out by cranking engine over. Next change oil and filter.

Now, start engine and see if problem can be duplicated. If problem can be duplicated, there

is probably a mechanical problem. If the problem cannot be duplicated, the problem is either

an operator error or a problem that exists only under certain environmental conditions.

If water is contained to cylinder(s) only, it is usually entering through the intake system,

exhaust system or head gasket.

If the water is contained to crankcase only, it is usually caused by a cracked or porous block,

a flooded bilge or condensation.

If the water is located in both the cylinder(s) and the crankcase, it is usually caused by water

in the cylinders getting past the rings and valves or complete submersion.

Check for rust in the intake manifold or exhaust manifolds. Rust in these areas will show that

if the water entered these areas.

If water is contained to cylinder(s) only, it is usually entering through the intake system,

exhaust system or head gasket.

Water In Crankcase

Cause Special Information

Water in boat bilge

Boat has been submerged or bilge water

was high enough to run in through dipstick

tube

Water seeping past piston rings or valves

Refer to “Water in Engine” (“On Top of

Pistons”)

Engine running cold

Defective thermostat, missing thermostat;

prolonged idling in cold water

Intake manifold leaking near a water

passage

Cracked or porous casting

Check cylinder head, cylinder block, and

intake manifold

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-30 90-861329--1 MARCH 1999

Water On Top Of Pistons

Cause Special Information

Operator shut engine off at high rpm

Engine “diesels” or tries to run backwards

Engine out of tune, poor fuel, high idle

rpm, timing set too high

Rain water running into flame arrestor Hatch cover

Spark plug misfiring

Improper combustion causes moisture in

the air to accumulate in the cylinder

Backwash through the exhaust system

Improper engine or exhaust hose

installation

Cracked exhaust manifold

Improper manifold to elbow gasket

installation

Loose cylinder head bolts

Blown cylinder head gasket

Check for warped cylinder head or

cylinder block

Cracked valve seat

Porous or cracked casting

Check cylinder heads, cylinder block, and

intake manifold

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-31

Engine Overheats

Mechanical

Cause Special Information

Engine rpm below specifications at

wide-open-throttle (engine laboring)

Damaged or wrong propeller; growth on

boat bottom; false bottom full of water

Wrong ignition timing Timing too far advanced or retarded

Sticking distributor advance weights

Spark plug wires crossed (wrong firing

order)

Lean fuel mixture

Refer to “Carburetor Malfunction” in this

section

Wrong heat range spark plugs

Exhaust restriction

Valve timing off

Jumped or improperly installed timing

chain

Blown head gasket(s)

A blown head gasket(s) normally cannot

be detected by a compression check.

Normally the engine will run at normal

temperature at low rpm, but will overheat

at speeds above 3000 rpm.

Engines that are seawater cooled:

Using a clear plastic hose, look for air

bubbles between seawater pump and

engine. If there are no bubbles present,

install clear plastic hose between

thermostat housing and manifold(s). If air

bubbles are present at a higher rpm, it is a

good indication there is a blown head

gasket.

Insufficient lubrication to moving parts of

engine

Defective oil pump, plugged oil passage,

low oil level

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-32 90-861329--1 MARCH 1999

Cooling System

Cause Special Information

IMPORTANT: The first step is to verify if

the engine is actually overheating or the

temperature gauge or sender is faulty

IMPORTANT: Best way to test gauge or

sender is to replace them.

Loose or broken drive belt

Seawater shutoff valve partially or fully

closed (if equipped)

Clogged or improperly installed sea

strainer

Loose hose connections between

seawater pickup and seawater pump inlet

(models with belt driven seawater pump

only)

Pump will suck air. Pump may fail to prime

or will force air bubbles into cooling

system.

Seawater inlet hose kinked or collapsed

Seawater pickup clogged

Obstruction on boat bottom causing water

turbulence

Obstruction will be in front of seawater

pickup, causing air bubbles to be forced

into cooling system

Defective thermostat

Exhaust elbow water outlet holes plugged

Insufficient seawater pump operation Worn pump impeller

Obstruction in cooling system such as

casting flash, sand, rust, salt, etc.

Refer to water flow diagram for engine

type being serviced

Engine circulating pump defective

Also refer to “Engine Overheats

(Mechanical)”

IMPORTANT: In addition to previous

checks, make the following checks if

engine is equipped with closed

cooling.

Low coolant level

Antifreeze not mixed properly

Antifreeze should be mixed 50/50 or

maximum 60/40 (60% antifreeze, 40%

water)

Heat exchanger cores plugged

Water hoses reversed at the water

distribution block

Refer to water flow diagram in SECTION 6

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-33

Power Steering

Poor, Erratic or No Assist

Cause Special Information

Drive belt Worn, broken or out of adjustment

Low fluid level

Air in system

Air leak in lines or pump, or air from

installation. Refer to SECTION 8A for

bleeding procedure.

Leaking hoses

Refer to SECTION 8A for bleeding

procedure.

Steering cables and/or steering helm

Cable or helm partially frozen from rust or

corrosion; cable over-lubricated; improper

cable installation

Binding in sterndrive unit

Refer to appropriate Sterndrive Service

Manual

Restriction in hydraulic hoses Causes loss of pressure

Control valve not positioned properly, not

balanced properly, or the mounting nut is

loose

Mounting bracket adjusting screw loose or

mounting tube is loose

Faulty pump Flow control valve may be sticking

Worn piston ring or scored housing bore in

cylinder

Causes loss of pressure

Leaking valve body or loose fitting spool

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-34 90-861329--1 MARCH 1999

Noisy Pump

Cause Special Information

Drive belt Check belt tension

Low fluid level

Air in fluid

Air leak in lines, pump, or air form

installation

Faulty pump

Use stethoscope to listen for noise in

pump

Restricted fluid passages

Kinks or debris in hoses or debris in

passages

Stop nut adjusted improperly

Refer to appropriate Sterndrive Service

Manual

Steering cables installed that do not meet

BIA standards

Refer to appropriate Sterndrive Service

Manual

Fluid Leaks

Cause Special Information

Loose hose connections

Refer to SECTION 8A for bleeding instruc-

tions

Damaged hose

Oil leaking from top of pump

System overfilled; fluid contains water;

fluid contains air

Cylinder piston rod seal

Faulty seals in valve

Faulty seals in O-rings in pump

Cracked or porous metal parts

IndexIndex

TROUBLESHOOTING

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 1C-35

Insufficient Water Flow From Alpha One Sterndrive Unit

Seawater Pickup Pump

Cause Special Information

Seawater shutoff valve partially or fully

closed (if equipped)

Water pickup clogged with foreign material

Kinked or broken bell housing to gimbal

housing water tube hose

Corroded through gimbal housing water

tube

Water pickup inserts warped. (Engine will

overheat while boat is underway.)

Water pickup must not protrude above

gear housing surface or inserts will create

an irregular or turbulent water flow over

the water pickup holes. Consequently, this

may cause loss of cooling water and

subsequent engine overheating. This

condition can be identified by cavitation

burn (pitting or erosion) on the gear

housing in the area aft of the water pick

up.

Damaged gear housing or accessories

improperly installed on boat bottom or

transom (speedometer pick up, depth

sounder transducer, etc.) Substantial

amount of barnacles or other marine

growth on gear housing or boat bottom.

(Engine will overheat while underway only)

An object or an irregularity on boat or gear

housing in area close to to water pickups

could create turbulence in water flow

going to water pickups. This could aerate

the water flow and cause engine to

overheat

Sterndrive installed too high on transom or

drive unit trimmed out too far out allowing

air to be drawn into pump. (Engine will

overheat while underway only)

Contact boat company if sterndrive is too

high. Instruct operator on proper trimming

technique if unit is trimmed out too far.

Bell housing-to-driveshaft housing O-ring

missing or damaged

Faulty seawater pickup pump

Seawater pickup tube corroded through

Driveshaft housing water pocket cover

cracked

Broken impeller blade or other obstruction

in water passages (usually lodges in drive-

shaft housing water pocket cover or cross

drilled water passage).

To check cross drilled water passages in

driveshaft housing, remove plug and pipe

plug located under decal on starboard side

of housing. Drive unit must be shifted into

reverse to remove pipe plug.

Water passage in driveshaft housing

improperly drilled

IndexIndex

TROUBLESHOOTING SERVICE MANUAL NUMBER 26

Page 1C-36 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

IndexIndex

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-1

REMOVAL AND INSTALLATION

Section 2A - MCM 3.0L (181 cid) - Alpha Drive

Table of Contents

Torque Specifications 2A-2. . . . . . . . . . . . . . . . . .

Lubricants/Sealers/Adhesives 2A-2. . . . . . . . . . .

Tools 2A-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal 2A-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Removal 2A-3. . . . . . . . . . . . . . . . . . . .

Installation 2A-8. . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Installation 2A-8. . . . . . . . . . . . . . . . . .

Engine Alignment 2A-11. . . . . . . . . . . . . . . . . .

Engine Connections 2A-13. . . . . . . . . . . . . . .

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-2 90-861329--1 MARCH 1999

Torque Specifications

DESCRIPTION lb-in. lb-ft Nm

Power Steering Hydraulic Hose Fittings 23 31

Front Engine Mounts 35 47

Rear Engine Mounts 38 52

Drive Unit Shift Cables (Cable End and

Cable End Guide)

Tighten Until Contacts, Then Loosen 1/2

Turn. Spread Cotter Keys

Remote Control Shift Cables

Remote Control Throttle Cables

Hose Clamps

Tighten Securely

Battery Cables

Lubricants/Sealers/Adhesives

Description Part Number

Quicksilver Engine Coupler Spline Grease 92-816391A4

Quicksilver 2-4-C Marine Lubricant With Teflon 92-825407A3

Quicksilver Liquid Neoprene 92-25711--3

Loctite Pipe Sealant with Teflon Obtain Locally

Tools

Description Part Number

Engine Alignment Tool 91-805475A1

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-3

Removal

IMPORTANT: Sterndrive unit must be removed prior to engine removal. Refer to

Sterndrive Service Manual.

Engine Removal

1. Disconnect battery cables from battery.

22052

a-Negative (-) Battery Cable

b-Positive (+) Battery Cable

c-Rubber Boot (Slid Back From Terminal)

2. Remove instrument harness connector plug from engine harness receptacle after loos-

ening clamp.

WARNING

Be careful when working on fuel system. Gasoline is extremely flammable and

highly explosive under certain conditions. Do not smoke or allow spark or open

flame in area. Wipe up any spilled fuel immediately.

3. Disconnect and plug fuel line to prevent fuel in tank from leaking into bilge.

50738

a-Fuel Pump

b-Disconnect Fuel Inlet Line Here

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-4 90-861329--1 MARCH 1999

4. Disconnect throttle cable from carburetor and retain locknuts and hardware.

75810

a-Cable End Guide

b-Throttle Cable Anchor Screw

c-Cable Barrel

d-Elastic Stop Nut And Flat Washer

e-Throttle Lever

5. Disconnect shift cables and shift assist assembly (if equipped).

75811

a-Locking Nut

b-Shift Cable End

c-Cotter Pin

d-Shift Assist Assembly

e-Clevis Pin (w/Cotter Pin)

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-5

6. Disconnect and cap power steering hoses. Plug control valve hose connection holes.

75812

a-Power Steering Hoses

b-Control Valve

7. Loosen clamp and unplug wiring harness.

50626

a-Engine Wiring Harness Receptacle (Bracket)

b-Instrumentation Wiring Harness

c-Hose Clamp

8. Disconnect bullet connectors of trim sender wires (coming from transom assembly) from

engine harness.

NOTE: After wires are disconnected, remove them from clamps or Sta-Straps retaining

them to engine or hoses.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-6 90-861329--1 MARCH 1999

9. Disconnect engine harness wires from shift cut-out switch harness.

75499

a-Shift Cutout Switch Wires

10. Disconnect MerCathode wires from MerCathode controller if equipped.

11. Disconnect seawater inlet hose from gimbal housing.

72614

a-Water Tube

b-Hose Clamp (Tighten Securely)

c-Water Hose

12. Loosen hose clamps and disconnect exhaust elbow hose.

13. Remove both shift cables from shift plate. Retain locknuts and hardware.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-7

14. Disconnect any grounding wires and accessories that are connected to engine.

50636

a-Ground Stud

15. Disconnect (and suitably plug) fluid hoses from power steering control valve on transom.

CAUTION

Center lifting eye (located on top of thermostat housing) is used for engine align-

ment only. DO NOT use to lift entire engine.

CAUTION

DO NOT allow lifting sling to hook or compress engine components or damage will

occur.

16. Support engine with suitable sling through lifting eyes on engine and remove front and

rear engine mounting bolts. Retain hardware.

75815

Typical

a-Center Lifting (Aligning) Eye

b-Lifting Eye

17. Carefully remove engine. DO NOT hit power steering control valve.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-8 90-861329--1 MARCH 1999

Installation

Engine Installation

1. Be certain fiber washers (cemented in place) on inner transom plate are present. Inspect

fiber washers. Replace if worn or damaged.

2. Install double wound lockwashers onto inner transom plate inside fiber washer.

72023

a-Double Wound Lockwasher

b-Fiber Washer

c-Inner Transom Plate Mount

d-Locknut

3. Be certain rear engine mount locknuts are in position as shown.

4. Lubricate exhaust bellows with soap and water to ease installation.

5. Lubricate engine coupling splines with Quicksilver Engine Coupler Spline Grease.

72017

a-Lubricate Splines With Quicksilver Engine Coupler Grease 92-816391A4

b-Grease Fitting

CAUTION

Center lifting eye (located on top of thermostat housing) is used for engine align-

ment only. DO NOT use to lift entire engine.

CAUTION

DO NOT allow lifting sling to hook or compress engine components or damage will

occur.

6. Attach a suitable sling to lifting eyes on engine and adjust so that engine is level when

suspended.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-9

7. Lift engine into position (in boat), using an overhead hoist.

75815

a-Center Lifting (Aligning) Eye

b-Lifting Eye

8. Align rear engine mounts with inner transom plate mounts while simultaneously aligning

exhaust tubes with exhaust pipe hoses (bellows). Do not fasten attaching hardware until

you have aligned engine.

75819

a-Bellows

b-Clamps

c-Exhaust Pipe

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-10 90-861329--1 MARCH 1999

IMPORTANT: Engine attaching hardware must be installed in sequence shown.

9. Install both rear engine mounting bolts and hardware as shown.

10. Torque mounting bolts to 38 lb-ft (52 Nm).

72535

a-Rear Engine Mounting Bolt

b-Large Steel Washer

c-Metal Spacer

d-Rear Engine Mount

e-Double Wound Lockwasher

f-Fiber Washer

g-Inner Transom Plate Mounts

h-Locknut (Hidden In This View)

CAUTION

When lowering engine into position DO NOT set engine on shift cable. Shift cable

outer casing can be crushed causing difficult or improper shifting.

11. Set engine down on stringers and relieve hoist tension. Disconnect sling from engine

lifting eyes and switch sling to center lifting eye.

75815

a-Center Lifting (Aligning) Eye

b-Lifting Eyes (rear lifting eye hidden in this view)

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-11

Engine Alignment

IMPORTANT: The modified 91-57797A3 tool or the new tool 91-805475A1 will align all

current Alpha One as well as all older engines that used the older 91-57797A3.

CAUTION

To avoid damage to gimbal bearing, engine coupler, or alignment tool:

w DO NOT attempt to force alignment tool!

w DO NOT raise or lower engine with alignment tool inserted (or partially inserted)

in gimbal bearing or engine coupler.

1. Attempt to insert solid end of Quicksilver Alignment Tool through gimbal bearing and into

engine coupler splines.

2. If Quicksilver Alignment Tool will not insert easily, while observing the above precau-

tions, CAREFULLY raise and lower front of engine with hoist. Continue as needed until

tool will SLIDE FREELY all the way in and out of engine coupler splines.

70013

a-Alignment Tool (91-805475A1)

b-Aligning End

72585

a-Alignment Tool

b-Gimbal Bearing

c-Engine Coupler

IMPORTANT: Turn both front engine mount adjustment nuts an equal amount in

direction required to align engine.

3. Adjust front engine mounts until they rest on boat stringers.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-12 90-861329--1 MARCH 1999

4. Relieve hoist tension entirely and fasten both front mounts to boat stringer using appro-

priate hardware (lag bolts or through-bolts, etc).

5. Recheck alignment with alignment tool. Tool must enter coupler splines freely. If not,

readjust front mounts.

6. When alignment is correct, tighten locknut or nut with lockwasher on each mount

securely.

22054

a-Front Mount

b-Attaching Bolts And Flat Washers

c-Adjustment Nut

d-Locknut

e-Jam Nut

7. Remove alignment tool if not already removed.

8. Tighten all exhaust system clamps securely as shown (use two clamps on each

connection).

50633

a-Hose Clamps

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-13

Engine Connections

IMPORTANT: When routing all wire harnesses and hoses, be sure they are routed and

secured to avoid coming in contact with hot spots on engine and avoid contact with

moving parts.

1. Connect seawater inlet hose to water tube at gimbal housing with hose clamp. Tighten

clamp securely.

72614

a-Water Inlet Tube

b-Hose Clamp

c-Seawater Inlet Hose

2. Connect instrument harness to engine harness with clamp. Tighten clamp securely.

50626

a-Engine Wiring Harness

b-Instrument Harness

c-Clamp

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-14 90-861329--1 MARCH 1999

3. Connect trim position sender leads from gimbal housing to leads from engine harness.

72992

a-BROWN/WHITE - From Engine Harness

b-BLACK - From Engine Harness

c-BLACK - From Transom Assembly

d-BLACK - From Transom Assembly

WARNING

Be careful when working on fuel system. Gasoline is extremely flammable and

highly explosive under certain conditions. Do not smoke or allow spark or open

flame in area. Wipe up any spilled fuel immediately.

4. Connect fuel line from fuel tank(s) to engine. Make certain connections are secure.

Check for leaks.

50738

a-Fuel Pump

b-Connect Flexible Fuel Inlet Line Here

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-15

5. Connect throttle cable using hardware retained and adjust as follows:

a. Place remote control handle(s) in NEUTRAL, idle position.

IMPORTANT: Be sure that cable is routed in such a way as to avoid sharp bends and/

or contact with moving parts. DO NOT fasten any items to throttle cable. Outer cable

must be free to move when cable is actuated.

75817

a-Anchor Bolt

b. Install cable end guide on throttle lever, then push cable barrel lightly toward throttle

lever end. (This will place a slight preload on cable to avoid slack in cable when

moving remote control lever.) Adjust barrel on throttle cable to align with anchor stud.

c. Secure throttle cable with hardware (retained) as shown. Tighten cable end guide

locknut until it contacts and then loosen one full turn. Tighten throttle cable anchor

screw securely. DO NOT OVERTIGHTEN, as cable must pivot freely.

75810

a-Cable End Guide

b-Throttle Cable Anchor Screw

c-Cable Barrel

d-Cable End Guide Locknut

e-Throttle Lever

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-16 90-861329--1 MARCH 1999

d. Place remote control throttle lever in the wide-open-throttle (W.O.T.) position.

Ensure that throttle shutters (valves) are completely open and throttle shaft lever

contacts carburetor body casting.

e. Return remote control throttle lever to idle position and ensure that throttle lever con-

tacts idle speed adjustment screw.

72283

a-Throttle Lever Tang

b-Carburetor Body

c-Idle Speed Adjustment Screw

d-Wide Open Throttle

e-Idle

50633

a-Throttle Lever

b-Idle Speed Adjustment Screw

IMPORTANT: Do not attach any accessory ground (–) wires to transom plate ground

point. Accessory ground wires should only be attached to ground stud on engine.

6. Connect any grounding wires or accessories that have been disconnected.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-17

7. Connect MerCathode wires to MerCathode controller assembly as shown, if equipped.

Apply a thin coat of Quicksilver Liquid Neoprene to all connections.

22232

a-ORANGE Wire - From Electrode on Transom Assembly

b-RED/PURPLE Wire - Connect Other End to Positive(+) Battery Terminal

c-BLACK Wire - From Engine Harness

d-BROWN Wire - From Electrode on Transom Assembly

IMPORTANT: Adjust shift cables as outlined in appropriate Sterndrive Service

Manual.

8. Refer to appropriate Sterndrive Service Manual. Install and adjust drive unit and remote

control shift cables, using hardware retained.

IMPORTANT: After fluid hose installation in the following, bleed power steering

system as outlined in SECTION 1B - “Maintenance” or refer to appropriate Sterndrive

Service Manual.

9. Connect power steering fluid hoses to control valve (large fitting first) as shown.

CAUTION

Route hoses exactly as shown below. This will help avoid stress on the hose fittings

and will help avoid kinks in the hose.

IMPORTANT: Make hydraulic connections as quickly as possible to prevent fluid

leakage.

IMPORTANT: Be careful not to cross-thread or overtighten fittings.

10. Torque fittings to 23 lb-ft (31 Nm).

73786

a-Power Steering Fluid Hose Fittings

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-18 90-861329--1 MARCH 1999

11. Connect battery cables to battery by FIRST connecting POSITIVE (+) battery cable

(usually RED) to POSITIVE (+) battery terminal.

12. Tighten clamps securely.

13. Connect NEGATIVE (–) battery cable (usually BLACK) to NEGATIVE (–) battery

terminal.

14. Tighten clamp securely.

NOTE: Spray terminals with a battery connection sealant to help retard corrosion.

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 2A-19

THIS PAGE IS INTENTIONALLY BLANK

INDEX

MCM 3.0L (181 CID) - ALPHA DRIVE SERVICE MANUAL NUMBER 26

Page 2A-20 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

INDEX

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-1

ENGINE

Section 3A - 181 cid (3.0L) 4 Cylinder GM Engine

Table of Contents

Torque Specifications 3A-3. . . . . . . . . . . . . . . . . .

Tools 3A-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Special Tools 3A-4. . . . . . . . . . . . . . . . . . . . . . .

Lubricants/Sealants/Adhesives 3A-5. . . . . . . . . .

Engine Specifications 3A-5. . . . . . . . . . . . . . . . . .

Cylinder Bore 3A-5. . . . . . . . . . . . . . . . . . . . . .

Piston Clearance 3A-5. . . . . . . . . . . . . . . . . . .

Piston Ring: Compression 3A-5. . . . . . . . . . .

Piston Ring: Oil 3A-6. . . . . . . . . . . . . . . . . . . . .

Piston Pin 3A-6. . . . . . . . . . . . . . . . . . . . . . . . .

Crankshaft 3A-6. . . . . . . . . . . . . . . . . . . . . . . . .

Camshaft 3A-6. . . . . . . . . . . . . . . . . . . . . . . . . .

Cylinder Head 3A-7. . . . . . . . . . . . . . . . . . . . . .

Valve System 3A-7. . . . . . . . . . . . . . . . . . . . . .

General 3A-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Engine Identification 3A-8. . . . . . . . . . . . . . . .

Engine Rotation 3A-8. . . . . . . . . . . . . . . . . . . .

Firing Order 3A-9. . . . . . . . . . . . . . . . . . . . . . . .

Priming Engine With Oil 3A-9. . . . . . . . . . . . . . . .

Tool Required 3A-9. . . . . . . . . . . . . . . . . . . . . .

Bearing Failures 3A-10. . . . . . . . . . . . . . . . . . . . .

Piston Failures 3A-12. . . . . . . . . . . . . . . . . . . . . . .

Pre-Ignition 3A-12. . . . . . . . . . . . . . . . . . . . . . .

Detonation 3A-13. . . . . . . . . . . . . . . . . . . . . . . .

Engine Mounts 3A-14. . . . . . . . . . . . . . . . . . . . . . .

Rocker Arm Cover 3A-15. . . . . . . . . . . . . . . . . . . .

Removal 3A-15. . . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-15. . . . . . . . . . . . . . . . . . . . . . . .

Push Rod Cover 3A-16. . . . . . . . . . . . . . . . . . . . .

Removal 3A-16. . . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-16. . . . . . . . . . . . . . . . . . . . . . . .

Rocker Arm/Push Rod 3A-17. . . . . . . . . . . . . . . .

Removal 3A-17. . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-17. . . . . . . . . . . .

Installation 3A-18. . . . . . . . . . . . . . . . . . . . . . . .

Valve Adjustment 3A-18. . . . . . . . . . . . . . . . . . . . .

Engine Not Running 3A-18. . . . . . . . . . . . . . .

Engine Running 3A-19. . . . . . . . . . . . . . . . . . .

Hydraulic Valve Lifters 3A-20. . . . . . . . . . . . . . . .

Locating Noisy Lifters 3A-20. . . . . . . . . . . . . .

Removal 3A-21. . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-21. . . . . . . . . . . .

Installation 3A-21. . . . . . . . . . . . . . . . . . . . . . . .

Valve Stem Oil Seal/Valve Spring 3A-22. . . . . . .

Replacing Oil Seal (Head Installed) 3A-23. .

Cylinder Head 3A-24. . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-25. . . . . . . . . . . .

Installation 3A-25. . . . . . . . . . . . . . . . . . . . . . . .

Cylinder Head and Valve Conditioning 3A-26. .

Disassembly 3A-26. . . . . . . . . . . . . . . . . . . . . .

Cleaning 3A-26. . . . . . . . . . . . . . . . . . . . . . . . .

Inspection 3A-27. . . . . . . . . . . . . . . . . . . . . . . .

Rocker Arm Studs 3A-28. . . . . . . . . . . . . . . . .

Valve Guide Bore Repair 3A-29. . . . . . . . . . .

Valve Springs - Checking Tension 3A-30. . . .

Valve Seats 3A-30. . . . . . . . . . . . . . . . . . . . . . .

Reassembly 3A-31. . . . . . . . . . . . . . . . . . . . . .

Dipstick Specifications 3A-33. . . . . . . . . . . . . . . .

All Engines 3A-33. . . . . . . . . . . . . . . . . . . . . . .

Oil Pan 3A-34. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal 3A-34. . . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-34. . . . . . . . . . . . . . . . . . . . . . . .

Oil Pump 3A-35. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal 3A-35. . . . . . . . . . . . . . . . . . . . . . . . .

Disassembly 3A-35. . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-36. . . . . . . . . . . .

Reassembly 3A-36. . . . . . . . . . . . . . . . . . . . . .

Installation 3A-36. . . . . . . . . . . . . . . . . . . . . . . .

Torsional Damper 3A-37. . . . . . . . . . . . . . . . . . . .

Removal 3A-37. . . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-37. . . . . . . . . . . . . . . . . . . . . . . .

Crankcase Oil Seal 3A-39. . . . . . . . . . . . . . . . . . .

Replacing Oil Seal Without Removing

Front Cover 3A-39. . . . . . . . . . . . . . . . . . . . . .

Crankcase Front Cover 3A-40. . . . . . . . . . . . . . .

Removal 3A-40. . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-40. . . . . . . . . . . .

Installation 3A-40. . . . . . . . . . . . . . . . . . . . . . . .

Flywheel and Engine Coupler 3A-41. . . . . . . . . .

Removal 3A-41. . . . . . . . . . . . . . . . . . . . . . . . .

Inspection 3A-41. . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-42. . . . . . . . . . . . . . . . . . . . . . . .

Rear Main Oil Seal 3A-43. . . . . . . . . . . . . . . . . . .

Removal 3A-43. . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-43. . . . . . . . . . . .

Installation 3A-43. . . . . . . . . . . . . . . . . . . . . . . .

Main Bearings 3A-44. . . . . . . . . . . . . . . . . . . . . . .

Inspection 3A-44. . . . . . . . . . . . . . . . . . . . . . . .

Checking Clearances 3A-45. . . . . . . . . . . . . .

Main Bearing Replacement 3A-46. . . . . . . . .

Connecting Rod Bearings 3A-47. . . . . . . . . . .

Inspection and Replacement 3A-47. . . . . . . .

Connecting Rod/Piston Assembly 3A-49. . . . . .

Removal 3A-49. . . . . . . . . . . . . . . . . . . . . . . . .

Disassembly 3A-49. . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-50. . . . . . . . . . . .

Reassembly 3A-51. . . . . . . . . . . . . . . . . . . . . .

Installation 3A-53. . . . . . . . . . . . . . . . . . . . . . . .

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-2 90-861329--1 MARCH 1999

Table of Contents (continued)

Crankshaft 3A-55. . . . . . . . . . . . . . . . . . . . . . . . . .

Removal 3A-55. . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-56. . . . . . . . . . . .

Installation 3A-56. . . . . . . . . . . . . . . . . . . . . . . .

Crankshaft Sprocket 3A-57. . . . . . . . . . . . . . . . . .

Removal 3A-57. . . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-57. . . . . . . . . . . . . . . . . . . . . . . .

Camshaft 3A-58. . . . . . . . . . . . . . . . . . . . . . . . . . .

Measuring Lobe Lift 3A-58. . . . . . . . . . . . . . . .

Removal 3A-58. . . . . . . . . . . . . . . . . . . . . . . . .

Inspection 3A-59. . . . . . . . . . . . . . . . . . . . . . . .

Camshaft Gear Replacement 3A-60. . . . . . .

Installation 3A-60. . . . . . . . . . . . . . . . . . . . . . . .

Camshaft Bearings 3A-62. . . . . . . . . . . . . . . . . . .

Removal 3A-62. . . . . . . . . . . . . . . . . . . . . . . . .

Inspection 3A-62. . . . . . . . . . . . . . . . . . . . . . . .

Installation 3A-62. . . . . . . . . . . . . . . . . . . . . . . .

Cylinder Block 3A-64. . . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 3A-64. . . . . . . . . . . .

Oil Filter By-Pass Valve 3A-68. . . . . . . . . . . . . . .

Inspection and/or Replacement 3A-68. . . . . .

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-3

Torque Specifications

Fastener Location lb-in. lb-ft Nm

Camshaft Sprocket Bolts 80 9

Connecting Rod Cap Nuts 45 61

Cylinder Head Bolts 90

122

Distributor Clamp 20 27

Engine Coupler to Flywheel 35 47

Flywheel Housing to Block 21 28

Flywheel to Crankshaft Bolts 65 88

Front Cover Bolts 27-35 3.4

Front Mount to Block 21 28

Main Bearing Cap Bolts 65 88

Center 20-25

27-34

Manifold to Head

Outer 15-20 20-27

Oil Pan Bolts-Crankcase 80 9

Oil Pan Bolts-to Front Cover 45 5

Oil Pan Studs to Oil Seal Retainer or Crankcase 15 1.7

Oil Pump Cover 72 8

Oil Pump to Block 120 14

Oil Pump Pickup 60 7

Rocker Arm Cover and Bolts 40 4.5

Rocker Arm Nuts

3/4 Turn Down From Zero

Lash

Push Rod Cover Bolts 40 4.5

Crankshaft Rear Oil Seal Retainer Nuts 150-180 17-20

Spark Plugs 22 30

Starter Motor to Block 37 50

Timing Gear Cover 72 8

Torsional Damper Bolt 50 68

Water Pump to Block 15 20

Retorque after first 20 hours of operation.

Retorque after first start-up.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-4 90-861329--1 MARCH 1999

Tools

Description Parts Number

Piston Ring Expander 91-24697

Torch Lamp 91-63209

Special Tools

KENT MOORE SPECIAL TOOLS

Kent-Moore Special Tools

29784 Little Mack

Roseville, MI 48066

Phone: (313) 574-2332

Description Parts Number

Valve Spring Compressor (Head on) J5892

Valve Spring Compressor (Head off) J8062

Valve Stem Seal Tester J23738-A

Valve Guide Reamer (Standard) J8814

Valve Guide Reamer (.015 in. oversize) J5830-02

Rocker Arm Stud Remover J5802-01

Rocker Arm Stud Installer J6880

Stud Bore Reamer (.003 in. oversize) J5715

Stud Bore Reamer (.013 in. oversize) J6036

Carbon Remover Brush J8089

Piston Support Tool J5910-04

Piston Pin Tool J24086-B

Piston Ring Groove Cleaner J3936-03

Piston Ring Compressor J8037

Connecting Rod Guide Tool (3/8-24) J5239

Cylinder Bore Checker J8087

Oil Pump Suction Pipe Installer J8369

Timing Cover Seal Aligner J23042-B

Cam Lobe Lift Indicator J8520

Camshaft Bearing Installer/Remover Tool J6098-01

Distributor Shaft Lower Bearing Installer/

Remover

J9534-01

Pulley Hub Puller J6978-E

Pulley Hub Installer J5590

Universal Torsional Damper Remover J24420-B

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-5

Lubricants/Sealants/Adhesives

Description Parts Number

Quicksilver Perfect Seal 92-34227--1

Quicksilver 2-4-C Marine Lubricant with

Teflon

92-825407A3

Quicksilver RTV Sealer 92-809826

Engine Specifications

NOTICE

Unit Of Measurement: U.S. Inches (Millimeters)

Model 3.0L

Displacement 181 cid (3.0L)

Cylinder Bore

Diameter 3.9995-4.0025 (101.588-101.790)

Production .0005 (0.012) Max

Out of Round

Service .002 (0.05) Max

Production

Thrust

Side

.0005 (0.012) Max

Taper

Production

Relief Side .0005 (0.012) Max

Service .001 (0.02) Max

Piston Clearance

Production .0025-.0035 (0.064-0.088) Max

Service .0035 (0.08) Max

Piston Ring: Compression

Top

Groove Clearance

Production

2nd

.0012-.0029 (0.030-0.073)

Service .003 (0.09) Max

Top

Gap

Production

2nd

.010-.020 (0.254-0.762)

Service .035 (0.88) Max

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-6 90-861329--1 MARCH 1999

Piston Ring: Oil

Production .001-.006 (0.026-0.152)

Groove

Clearance

Service

Limit

.007 (0.17) Max

Production .010-.030 (0.254-0.762) Max

Gap

Service

Limit

.040 (1.01) Max

Piston Pin

Diameter .9270-.9271 (23.546-23.550)

Production .0003-.0006 (0.008-0.016)

Clearance

Service

Limit

.001 (0.02) Max

Fit in Rod .0008-.0019 (0.020-0.050) Interference

Crankshaft

Diameter 2.2979-2.294 (58.367-58.404)

Main

Production .0002 (0.005) Max

Journal

Taper

Service .001 (0.02) Max

Out of

Production .0002 (0.005) Max

Out of

Round

Service .001 (0.02) Max

Production No.1-No.4 .001-.0024 (0.025-0.060)

Main

Service No.5 .0016-.0035 (0.041-0.088)

Bearing

Clearance

Production No.1-No.4 .001-.0025 (0.03-0.06)

Clearance

Service No.5 .002-.0035 (0.05-0.08)

Crankshaft End Play .002-.006 (0.05-0.15)

Diameter 2.09980-20995 (53.289-53.327)

Production .0003 (0.007) Max

Crankpin

Taper

Service .001 (0.02) Max

Out of

Production .0002 (0.51) Max

Out of

Round

Service .001 (0.02) Max

Rod

Production .0017-.0027 (0.044-0.0686)

Bearing

Clearance

Service

Rod Size Clearance .006-.017 (0.153-0.4318) Max

Camshaft

Intake .2529 (6.425)

Lobe Lift (Max.)

Exhaust .2529 (6.425)

Journal Diameter 1.8677-18697 (47.440-47.490)

Camshaft End Play .003-.008 (0.08-0.2032) Max

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-7

Cylinder Head

Gasket Surface Flatness

.003-.008 in any 6 in. (152) or .007

(0.15) Overall Max

Valve System

Lifter Hydraulic

Rocker Arm Ratio 1.75 to 1

Collapsed Tappet Gap 3/4 Turn Down from Zero Lash

Intake 45°

Face Angle

Exhaust 45°

Seat Angle (Intake & Exhaust) 46°

Seat Runout (Intake & Exhaust) .002 (0.05) Max

Intake 1/16 (.0625 in.) (1.16 mm)

Seat Width

Exhaust 1/16-5/64 [.0625-.07812 in.] (1.6-2.0 mm)

Intake .0010-.0027 (0.025-0.069)

Stem

Production

Exhaust .0007-.0027 (0.018-0.069)

Stem

Clearance

Intake .003 (0.09) Max

Service

Exhaust .004 (0.11) Max

Free Length 2-1/16 in. (52 mm)

Valve

Closed

100-110 lb. (136-149 N) at 1-19/32 in. (41 mm)

Spring

Pressure

Valve

Open

208-220 lb. (282-300 N) at 1-7/32 in. (31 mm)

Installed

Intake

Height ±

.031(8)

Exhaust

(1/32) 1.6562 (42)

Internal Damper None

General

Some of the repairs in this section must be completed with engine removed from boat.

Engine removal depends upon type of repair and boat design. Place engine on repair stand

for major repairs.

When engine removal is not required, make certain that battery cables are disconnected

at the battery prior to performing any on-board engine repair procedure.

Lubricate all moving parts (during reassembly) with engine oil. Apply Quicksilver Perfect

Seal on threads of and under heads of cylinder head bolts, and on threads of all cylinder

block external bolts, screws and studs.

Model No. of Cylinders cu-in./liters Displacement

MCM 3.0L 4 181 (3L)

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-8 90-861329--1 MARCH 1999

Engine Identification

The MerCruiser Model can be determined by looking at the LAST TWO LETTERS of the

engine code stamped into the cylinder block. This code number is stamped on all

MerCruiser power packages and replacement partial engines, but not replacement cylinder

block assemblies.

If the engine serial number and/or model decals are missing, the engine code letters may

help in determining the engine models.

74520

G.M. Engine Code Location 3.0L -

RX (12-3/4 in. or 324 mm flywheel) - S/N 0L096999 and below

RP (14 in. or 356 mm flywheel) - S/N 0L097000 and above

a-4 Cylinder-In-Line Engine Code (Next To Distributor)

Engine Rotation

Engine rotation terminology at times has caused confusion. To clarify, engine rotation is

determined by observing flywheel rotation from the rear (transmission or sterndrive end) of

the engine looking forward (water pump end).

PROPELLER ROTATION IS NOT NECESSARILY THE SAME as engine rotation. Do not

rely on propeller rotation in determining engine rotation.

72001

a-Left-Hand Rotation (CCW)

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-9

Firing Order

50683

Firing Order 1-3-4-2

Priming Engine With Oil

IMPORTANT: This applies to all power packages that have not been run within 6

months, replacement of partial engines or after rebuilding an engine.

Tool Required

71089

Remote Starter Kit (91-52024A1)

1. Fill crankcase to proper level with the recommended engine oil.

2. Remove spark plugs.

3. Leave ignition key in “OFF” position.

4. Connect remote starter switch to large 12 V terminal (RED battery cable) and small ter-

minal (RED/YELLOW) wire on starter motor.

a. If remote starter switch is not available, disconnect PURPLE wire from ignition coil

before using key switch to crank the engine over. Tape terminal on PURPLE wire to

prevent it from touching ground.

5. Crank engine for 15 seconds, then allow starter motor to cool down for 1 minute. This

should prevent starter motor from overheating.

6. Repeat this process until a total of 45 seconds of cranking time is achieved.

7. Remove remote starter switch.

a. If key switch was used, reconnect PURPLE wire to ignition coil.

8. Install spark plugs and wires

9. Supply cooling water to seawater pump and start motor.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-10 90-861329--1 MARCH 1999

Bearing Failures

70436

Scratched By Dirt

a-Scratches

b-Dirt Imbedded In Bearing Material

70436

Tapered Journal

a-Overlay Gone From Entire Surface

70436

Lack Of Oil

a-Overlay Worn Off

70436

Radius Ride

a-Worn Area

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-11

70436

Improper Seating

a-Bright Or Polished Sections

70436

Fatigue Failure

a-Craters or Pockets

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-12 90-861329--1 MARCH 1999

Piston Failures

Pre-Ignition

Pre-ignition is abnormal fuel ignition, caused by combustion chamber hot spots. Control of

the start of ignition is lost, as combustion pressure rises too early, causing power loss and

rough running. The upward motion on the piston is opposed by the pressure rise. This can

result in extensive damage to the internal parts from the high increase in combustion cham-

ber temperature.

72424

Pre-Ignition Damage

CAUSES

1. Hot spots in the combustion chamber from glowing deposits (due in turn to the use of

improper oils and/or fuels).

2. Overheated spark plug electrodes (improper heat range or defective plug).

3. Any other protuberance in the combustion chamber, such as an overhanging piece of

gasket, an improperly seated valve or any other inadequately cooled section of material

which can serve as a source.

Engine failures that result from the foregoing conditions are beyond the control of Mercury

Marine. No warranty will apply to failures which occur under these conditions.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-13

Detonation

Detonation, commonly called “fuel knock,” “spark knock” or “carbon knock,” is abnormal

combustion of the fuel which causes the fuel to explode violently. The explosion causes

overheating or damage to the spark plugs, pistons, valves and, in severe cases, results in

pre-ignition.

CAUSES

IMPORTANT: Use of improper fuels will cause engine damage and poor performance.

1. Use of low octane gasoline is one of the most common causes of detonation. Even with

high octane gasoline, detonation could occur if engine maintenance is neglected.

2. Over-advanced ignition timing.

3. Lean fuel mixture at or near full throttle (could be caused by carburetor or leaking intake

manifold).

4. Cross-firing spark plugs.

5. Excess accumulation of deposits on piston and/or combustion chamber (results in

higher compression ratio).

6. Inadequate cooling of engine by deterioration of cooling system.

Engine failures that result from the foregoing conditions are beyond the control of

MerCruiser. No warranty will apply to failures which occur under these conditions.

72425

Detonation Damage

72315

a-Spark Occurs

b-Combustion Begins

c-Combustion Continues

d-Detonation Occurs

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-14 90-861329--1 MARCH 1999

Engine Mounts

74275

Front Mount

72318

Rear Mount/Flywheel Housing

a-Press Mount Out With Press

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-15

Rocker Arm Cover

Removal

It may be necessary to remove exhaust manifold before removing rocker arm cover. Refer

to SECTION 7B for removal.

1. Disconnect crankcase ventilation hose.

2. Remove any items that interfere with the removal of rocker arm covers.

IMPORTANT: DO NOT pry rocker arm cover loose. Gaskets, which may adhere to cyl-

inder head and rocker arm cover, may be loosened by bumping end of rocker cover

from the rear with palm of hand or a rubber mallet.

3. Remove rocker arm cover.

Installation

1. Clean sealing surfaces on cylinder head and rocker arm cover with degreaser.

2. Place new rocker arm cover gasket in position in rocker arm cover.

3. Install rocker arm cover. Torque bolts to 40 lb-in. (4.5 Nm).

4. Install exhaust manifolds.

5. Install any items which were removed to allow removal of rocker arm covers.

6. Connect crankcase ventilation hose to rocker arm cover.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-16 90-861329--1 MARCH 1999

Push Rod Cover

Removal

1. Remove the pushrod cover bolts.

2. Remove the pushrod cover.

3. Remove the gasket.

76247

Installation

1. Clean sealing surfaces on pushrod cover with degreaser.

2. Install new pushrod cover gasket in position.

3. Install pushrod cover. Torque bolts to 40 lb-in. (4.5 Nm).

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-17

Rocker Arm/Push Rod

74287

Valve Mechanism

a-Nut

b-Ball Unit

c-Rocker Arm

d-Push Rod

e-Rocker Arm Stud

Removal

NOTE: When servicing only one cylinder’s rocker arms, bring that cylinder’s piston up to

TDC before removing rocker arms. When servicing all rocker arms, bring No. 1 piston up

to TDC before removing rocker arms.

1. Remove rocker arm covers as outlined.

2. Remove rocker arm assemblies and push rods.

76232

IMPORTANT: Place rocker arm assemblies and push rods in a rack for reassembly

in their original locations.

Cleaning and Inspection

1. Clean parts with solvent and dry with compressed air.

2. Inspect all contact surfaces for wear. Replace all damaged parts.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-18 90-861329--1 MARCH 1999

Installation

IMPORTANT: When installing rocker arms and rocker arm balls, coat bearing sur-

faces of rocker arms and rocker arm balls with engine oil.

1. Install push rods in their original locations. Be sure push rods seat in lifter socket.

2. Install rocker arms, rocker arm balls and rocker arm nuts in their original locations.

76232

3. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly.

Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned

down 3/4 turn from zero lash position.

4. Adjust carburetor idle speed and mixture.

Valve Adjustment

Engine Not Running

With valve cover removed, adjust valves when lifter is on low part of camshaft lobe, as

follows:

1. Crank engine with starter or turn over in normal direction of rotation until mark on

torsional damper lines up with center “0” mark on timing tab, and engine is in No. 1 firing

position. This may be determined by placing fingers on No. 1 valve as mark. If valves

move as mark comes up to timing tab, engine is in No.4 firing position and should be

turned over one more time to reach No. 1 position.

50770

Typical

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-19

2. With engine in No. 1 firing position as determined above, the following valves may be

adjusted:

• No. 1 Cylinder - Exhaust and Intake

• No. 2 Cylinder - Intake

• No. 3 Cylinder - Exhaust

• No. 4 Cylinder - Intake

3. Loosen adjusting nut until lash is felt at push rod, then tighten adjusting nut until all lash

is removed. This can be determined by moving push rod up and down while turning

adjusting nut until all play is removed.

72300

4. Hydraulic lifters can be adjusted by tightening adjustment nut an additional 3/4-turn.

Valve lash should be checked after engine has run and reached operating temperature.

5. Crank engine one revolution until pointer “0” mark and torsional damper mark are again

in alignment. This is No. 4 firing position. With engine in this position, the following valves

may be adjusted:

• No. 2 Cylinder - Exhaust

• No. 3 Cylinder - Intake

• No. 4 Cylinder - Exhaust

6. Repeat steps 3-4 to adjust other valves.

7. Install Distributor cap, spark plug wires and coil lead.

8. Install rocker arm cover; torque to 40 lb-in. (4.5 Nm).

Engine Running

Following procedure should be completed only if readjustment is required.

1. Run engine until it reaches normal operating temperature, then remove valve cover.

2. With engine running at idle, loosen valve rocker arm nut until valve rocker arm starts to

clatter.

3. Turn rocker arm nut down slowly until clatter just stops. This is zero lash position.

4. Tighten nut 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat

additional 1/4 turns, pausing 10 seconds each time, until nut has been tightened 3/4 turn

from zero lash position.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-20 90-861329--1 MARCH 1999

IMPORTANT: The following preload adjustment must be done slowly to allow lifter to

adjust itself, thus preventing possibility of the valve head contacting the top of

piston, which may result in internal damage and/or bent push rods.

5. Repeat Steps 2-4 to adjust other valves.

6. Install rocker arm cover, torque to 40 lb-in. (4.5 Nm).

7. Adjust carburetor idle mixture and idle speed. Check for leaks.

Hydraulic Valve Lifters

Hydraulic valve lifters require little attention. Lifters are extremely simple in design.

Normally, readjustments are not necessary and servicing requires only that care and

cleanliness be exercised in the handling of parts.

Locating Noisy Lifters

Locate a noisy valve lifter by using a piece of garden hose approximately 4 ft (1.2 m) in

length. Place one end of hose near end of each intake and exhaust valve, with other end

of hose to the ear. In this manner, sound is localized, making it easy to determine which lifter

is at fault.

Another method is to place a finger on face of valve spring retainer. If lifter is not functioning

properly, a distinct shock will be felt when valve returns to its seat.

General types of valve lifter noise are as follows:

1. Hard rapping noise - usually caused by plunger becoming tight in bore of lifter body so

that return spring cannot push plunger back up to working position. Probable causes

are:

• Excessive varnish or carbon deposit, causing abnormal stickiness.

• Galling or “pickup” between plunger and bore of lifter body, usually caused by an abra-

sive piece of dirt or metal wedged between plunger and lifter body.

2. Moderate rapping noise - probable causes are:

• Excessively high leakdown rate.

• Leaky check valve seat.

• Improper adjustment.

3. General noise throughout valve train - this will, in most cases, be a definite indication

of insufficient oil supply or improper adjustment.

4. Intermittent clicking - probable causes are:

• A microscopic piece of dirt momentarily caught between ball seat and check valve ball.

• In rare cases, ball itself may be out of round or have a flat spot.

• Improper adjustment.

In most cases, where noise exists in one or more lifters, all lifter units should be removed,

disassembled, cleaned in solvent, reassembled and reinstalled in engine. If dirt, corrosion,

carbon, etc., exists in one unit, it probably exists in all units. It would only be a matter of time

before all lifters caused trouble.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-21

Removal

1. Remove as previously outlined:

a. Rocker arm covers.

b. Push rod cover.

IMPORTANT: Keep valve push rod and hydraulic lifter from each valve together as a

matched set and mark or store them so they can be reinstalled in the same location

later.

c. Rocker arm assemblies and push rods.

2. Make matching marks on all lifters as to location and orientation in bores, to allow reas-

sembly in exact position on camshaft lobes (so that the roller’s bearing and roller will roll

in the same direction on the same lobe, if reused). Remove valve lifters.

Cleaning and Inspection

1. Thoroughly clean all parts in cleaning solvent and inspect them carefully.

2. If any parts are damaged or worn, entire lifter assembly should be replaced.

3. If outer lifter body wall is scuffed or worn, inspect cylinder block lifter bore.

4. If push rod seat is scuffed or worn, inspect push rod.

Installation

IMPORTANT: It is recommended that the engine oil be changed and a new oil filter be

installed whenever servicing valve lifters or camshaft

IMPORTANT: Before installing lifters, coat the lifter with engine oil. If new lifters or

a new camshaft have been installed, an additive containing EP lube (such as General

Motors Cam and Lifter Prelube or equivalent) should be poured over camshaft lobes

before installing lifters.

IMPORTANT: DO NOT install used valve lifters if a new camshaft has been installed.

1. Install valve lifters into bores.

2. Install push rod cover, using new gaskets and torque to specification.

3. Install distributor, positioning rotor to number 1 cylinder position, then connect primary

lead at coil.

4. Install distributor cap and spark plug wires.

5. Adjust valves to specifications.

6. Install rocker arm cover, torque tp 40 lb-in. (4.5 Nm).

7. Adjust ignition timing, carburetor idle speed and mixture.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-22 90-861329--1 MARCH 1999

Valve Stem Oil Seal/Valve Spring

76248

a-Keys (2 per Valve)

b-Cap

c-Seal

d-Valve Spring Shield

e-Valve Spring

f-Valve

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-23

Replacing Oil Seal (Head Installed)

1. Remove rocker arm cover.

2. Remove spark plug, rocker arm and push rod on cylinder to be serviced.

3. Place piston for that cylinder at TDC to prevent valves from dropping into the cylinder.

4. Compress valve spring with tool (J-5892) and remove valve keys, valve spring cap,

spring shield and valve spring.

72881

a-Valve Spring Compressor (J-5892)

b-Rocker Arm Nut

5. Remove valve stem oil seal.

6. To install, set valve spring, (close, coiled end of spring is installed against cylinder head)

valve shield and valve cap in place. Compress spring with tool (J-5892) and install oil

seal in lower groove of stem, making sure that seal is flat and not twisted.

NOTE: A light coat of oil on seal will help prevent twisting when compressor tool is released.

IMPORTANT: Do not turn crankshaft while valve springs, retainers, and locks are

removed or valves will fall into cylinder.

7. Install valve keys and release compressor tool. Be sure that keys seat properly in upper

groove of valve stem.

8. Install and adjust valve mechanism.

9. Install push rods and rocker arm assemblies.

10. Torque rocker arm nuts as described in “Specifications.”

11. Install rocker arm cover and torque to 40 lb-in. (4.5 Nm).

12. Install spark plug and torque to 22 lb-ft (30 Nm).

13. Repeat steps 2 through 8 for other cylinders.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-24 90-861329--1 MARCH 1999

Cylinder Head

Cylinder Head Torque Sequence

1. Drain engine cooling system.

2. Remove as outlined:

a. Exhaust manifolds.

b. Intake manifold.

c. Rocker arm cover.

d. Pushrod cover.

e. Rocker arm assemblies and push rods (keep in order for reassembly in their original

locations).

76232

f. Any components attached to front or rear of cylinder head.

g. Spark plugs.

h. Head bolts.

CAUTION

The head gasket may be holding cylinder head to block. Use care when prying off

cylinder heads. DO NOT damage gasket surfaces. DO NOT drop cylinder heads.

3. Place cylinder head on wooden blocks to prevent damage to gasket surfaces.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-25

Cleaning and Inspection

1. Clean gasket material and sealer from engine block and cylinder heads.

2. Inspect sealing surfaces for deep nicks and scratches.

3. Inspect for corrosion around cooling passages.

4. Clean head bolt threads and engine block bolt hole threads, making sure no dirt, old oil

or coolant remains.

Installation

CAUTION

When using ribbed stainless steel head gaskets, apply a thin coating of Quicksilver

Perfect Seal to both sides of gasket. Too much sealer may hold gasket away from

head or block causing leakage. DO NOT use sealer on graphite composition head

gaskets.

1. Place head gasket in position over dowel pins.

2. Carefully set cylinder head in place over dowel pins.

3. Coat threads of head bolts with Quicksilver Perfect Seal and install finger-tight.

4. Torque head bolts to 90 lb-ft (122 Nm).

5. Install push rods, rocker arm assemblies and lifter restrictors in their original positions.

6. Torque rocker arm nuts to 20 lb-ft (27 Nm).

7. Install as outlined:

a. Intake/exhaust manifold.

b. Rocker arm cover.

c. Spark plugs.

d. Any components removed from front or rear of cylinder heads.

8. Follow procedures in SECTION 6A or 6B of this manual:

Seawater Cooled Models: Provide for adequate water supply to seawater pickup (see

SECTION 6A).

Closed Cooled Models: Refill closed cooling section (see SECTION 6B) and provide ade-

quate water supply to seawater pickup.

CAUTION

Ensure that cooling water supply is available before starting the engine.

9. Start engine, set timing, set idle speed and check for leaks.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-26 90-861329--1 MARCH 1999

Cylinder Head and Valve Conditioning

Disassembly

1. Using valve spring compressor, compress valve spring (J-8062) and remove valve

locks. Slowly release tool.

2. Remove all valve components.

3. Remove valves from cylinder head and place in a rack, in order, for reassembly in their

original locations.

72333

a-Valve Spring Compressor (J-8062)

Cleaning

1. Clean push rods and rocker arm assemblies.

2. Clean carbon from valves using tool (J-80890).

3. Clean gasket material from cylinder head mating surfaces.

4. Clean all carbon from combustion chambers and valve ports using carbon remover

brush.

74274

a-Carbon Remover Brush (J-8089)

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-27

5. Thoroughly clean valve guides with valve guide cleaner (J-8101).

74286

a-Valve Guide Cleaner (J-8101)

Inspection

1. Inspect cylinder head for cracks in exhaust ports, water jackets and combustion cham-

bers (especially around spark plug holes and valve seats). Replace heads if any cracks

are found.

2. Inspect cylinder head gasket surface for burrs, nicks, erosion or other damage. Check

flatness of cylinder head gasket surface, using a machinist’s straight edge and feeler

gauges as shown. Take measurements diagonally across head (both ways) and straight

down center head. Refer to “Specifications.”

72885

a-Straight Edge

b-Feeler Gauge

IMPORTANT: Cylinder head-to-block gasket surface should be resurfaced if warped

more than specified. When head resurfacing is required, cylinder head-to-intake

manifold gasket surface on head must be milled to provide proper alignment

between intake manifold and head.

3. Inspect valves for burned heads, cracked faces or damaged stems.

IMPORTANT: Excessive valve stem to bore clearance will cause excessive oil

consumption and possible valve breakage. Insufficient clearance will result in noisy

and sticky valves.

4. Measure valve stem clearance as follows:

a. Attach a dial indicator to cylinder head, positioning it against the valve stem and

close to the valve guide.

b. Holding valve head off seat about 1/16 in. (2 mm), move valve stem back and forth

in direction shown. Compare stem clearance with specifications.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-28 90-861329--1 MARCH 1999

c. If clearance exceeds specifications, it will be necessary to ream valve guides for

oversized valves, as outlined under “Valve Guide Bore Repair.”

72336

a-Valve Stem

b-Dial Indicator

c-Valve Guide

Rocker Arm Studs

Rocker arm studs with damaged threads or with loose fit in cylinder heads should be

replaced with new, oversize studs. Studs may be installed after reaming holes as follows:

1. Drain water from cylinder block.

2. Remove old stud by placing Tool J-5802-1 over stud, installing nut and flat washer and

turning the nut to remove stud.

74288

a-Tool J-5802-01

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-29

3. Ream hole for oversize stud with Tool J-5715 for .003 in. oversize or Tool J-6036 for .013

in. oversize.

74289

a-Reamer Tool J-5715

IMPORTANT: Do not attempt to install an oversize stud without reaming stud hole.

4. Coat press-fit area of stud with Perfect Seal. Install new stud, using Tool J-6880 as a

guide. Gauge should contact head.

Valve Guide Bore Repair

IMPORTANT: Be sure to measure valve stem diameter of both the intake and exhaust

valve, as valve stem diameter may or may not be the same for both valves.

If .015 in. oversize valve stems are required, ream valve guide bores for oversize valves,

as follows:

1. Measure valve stem diameter of old valve being replaced and select proper size valve

guide reamer from chart below.

2. Ream valve guide bores, as shown.

72886

3. Remove the sharp corner created by reamer at top of valve guide.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-30 90-861329--1 MARCH 1999

Valve Springs - Checking Tension

Using valve spring tester, as shown, check valve spring tension with dampers removed.

Refer to “Specifications.”

IMPORTANT: Springs should be replaced if not within 10 lbs. (44 N) of specified

tension.

72308

a-Valve Spring Tester (J-8056)

b-Torque Wrench

Valve Seats

Valve seat reconditioning is very important, since seating of valves must be perfect for

engine to deliver maximum power and performance.

Another important factor is valve head cooling. Good contact between each valve and its

seat in head is important to ensure that heat in valve head will be properly dispersed.

Several different types of equipment are available for reseating valve seats. Equipment

manufacturer’s recommendations should be followed carefully to attain proper results.

Regardless of type of equipment, however, it is essential that valve guide bores be free from

carbon or dirt to achieve proper centering of pilot in valve guide and ensure concentricity.

72338

a-Check Valve Seat Concentricity

Valves that are pitted must be refaced to the proper angle. Valve stems which show exces-

sive wear or valves that are warped excessively must be replaced. When a valve head that

is warped excessively is refaced, a knife edge will be ground on part or all of the valve head

due to the amount of metal that must be removed to completely reface. Knife edges lead

to breakage, burning or pre-ignition due to heat localizing on this knife edge. If the edge of

the valve head (margin) is less than 1/32 in. (0.8 mm) after grinding, replace the valve.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-31

Several different types of equipment are available for refacing valves. The recommendation

of the manufacturer of the equipment being used should be carefully followed to attain

proper results.

50695

Exhaust Intake

a-.372 In. (9.45 mm)

b-1/32 [.031] In. (0.79 mm) Min.

c-.341 In. (8.16 mm)

d-1/32 [.031] In. (0.79 mm) Min.

Reassembly

1. Lubricate valve guides and valve stems with engine oil.

2. Install each valve in the port from which it was removed or to which it was fitted.

3. Install valve guide seal (intake valve only) over valve stem and push down until seated

against head.

4. Set valve spring (with damper installed) and cap in place.

5. Place retainer on intake valve and/or rotator on exhaust valve.

6. While compressing valve spring with valve spring compressor, install oil seal in lower

groove of valve stem, making sure seal is not twisted. A light coating of oil will help

prevent twisting.

72884

V6 Shown

a-Valve Spring Compressor (J-8062)

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-32 90-861329--1 MARCH 1999

7. Install valve locks (grease may be used to hold them in place) and slowly release tool,

making sure locks seat properly in upper grooves of valve stem.

76249

1-Valve Locks

2-Retainer

3-Rotator

4-Cap

5-Valve Guide Oil Seal

6-Valve Stem Oil Seal

7-Outer Spring

8-Intake Valve

9-Exhaust Valve

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-33

8. Check installed height of valve springs using a narrow, thin scale. Measure from spring

seat to top of valve spring, as shown. If measurement exceeds specified height, install

a valve spring shim and recheck. DO NOT shim valve springs to give an installed height

less than the minimum specified.

05037

72339

Checking Valve Spring Installed Height

a-Cut Out This Portion

b-Valve Spring Installed Height

Dipstick Specifications

All Engines

NOTICE

Unit Of Measurement: U.S. inches (millimeters)

1/2

(13)

25-7/16

(646)

3/4

(19)

26-7/8

(682)

72887

41092-1 MCM

a-Full

b-Add

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-34 90-861329--1 MARCH 1999

Oil Pan

a-Oil Pan Gasket

Removal

1. Disconnect battery.

NOTE: Removal of engine from boat may be required.

2. Drain crankcase oil.

3. Remove starter motor.

4. Remove oil pan screws, oil pan and gasket(s).

Installation

1. Clean sealing surfaces of engine block and oil pan.

2. Apply a small amount of Quicksilver RTV Sealer to joints of rear seal retainer and joints

of front cover.

IMPORTANT: Quicksilver RTV Sealer sets up in about 15 minutes. Be sure to com-

plete assembly promptly.

3. Install oil pan gasket in position as shown.

NOTE: A one-piece oil pan gasket may be reused if it is still pliable and is not cracked, torn

or otherwise damaged.

4. Install oil pan. Starting from the center and working outward in each direction, tighten

1/4-20 threaded fasteners to 80 lb-in. (9 Nm) and 5/16-18 threaded fasteners to 165 lb-

in. (19 Nm).

5. Install dipstick tube and dipstick.

6. Fill crankcase with required quantity of oil of specified viscosity. See SECTION 1B

“Maintenance.”

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-35

Oil Pump

The oil pump consists of two gears and a pressure regulator valve enclosed in a two-piece

housing. Oil pump is driven by distributor shaft which is driven by a helical gear on camshaft.

Removal

1. Remove oil pan as previously outlined.

2. Remove gasket carefully as the one-piece gasket for the oil pan may be reused if still

pliable and not cracked, torn, etc.

3. Remove oil pump.

76234

a-Oil Pump

Disassembly

1. Remove pump cover.

IMPORTANT: Mark gear teeth for reassembly with same teeth indexing.

2. Remove idler gear and drive gear from pump body.

3. Remove retaining pin, spring, and pressure regulator valve from pump cover.

IMPORTANT: Do not remove pickup screen and pipe assembly, unless replacement

is necessary. Loss of press fit condition could result in an air leak and loss of oil pres-

sure.

IMPORTANT: Do not disturb pickup screen on pipe. This is serviced as an assembly.

4. If pickup screen and pipe assembly requires replacement, mount pump in a soft-jawed

vise and extract pipe from pump.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-36 90-861329--1 MARCH 1999

Cleaning and Inspection

1. Wash all parts in cleaning solvent and dry with compressed air.

2. Inspect pump body and cover for cracks or excessive wear.

3. Inspect pump gears for damage and excessive wear.

4. Check for loose drive gear shaft in pump body.

5. Inspect inside of pump cover for wear that would permit oil to leak past ends of gears.

IMPORTANT: Pump gears and body are not serviced separately. If pump gears or

body are damaged or worn, replacement of entire oil pump assembly is necessary.

6. Inspect pickup screen and pipe assembly for damage to screen and pipe.

7. Check pressure regulator valve for fit.

Reassembly

CAUTION

Be careful of twisting, shearing or collapsing pipe while installing in pump. Pickup

screen must be parallel to oil pan bottom when oil pump is installed.

If pickup screen and pipe assembly was removed, mount pump in a soft-jawed vise, apply

Quicksilver Perfect Seal to end of new pipe and, using oil pump suction pipe installer

(J-21882), tap the pipe in place with a hammer.

IMPORTANT: Oil internal parts liberally before installation.

1. Install pressure regulator valve and related parts.

2. Install drive gear in pump body.

3. Install idler gear in pump body with smooth side of gear toward pump cover opening.

Align marks made in disassembly.

4. Fill gear cavity with engine oil.

5. Install pump cover and torque attaching bolts to 80 lb-in. (9 Nm).

Installation

1. Install pump to rear main bearing.

2. Torque oil pump bolt to 65 lb-ft (88 Nm).

3. Install oil pan as outlined. The one-piece gasket for the oil pan may be reused if still

pliable and not cracked, torn, etc.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-37

Torsional Damper

Removal

1. Support front of engine (if in boat) with overhead hoist.

2. Remove front mounting bracket and drive belt. Remove retaining bolt, if equipped.

3. Install tool J-6978-E to balancer and turn puller. Remove drive pulley, then remove

torsional damper retaining bolt.

IMPORTANT: DO NOT use a universal claw type puller to remove torsional damper

(in next step) as outside ring of torsional damper is bonded in rubber to the hub and

use of claw type puller may break the bond.

4. Remove torsional damper with torsional damper remover and installer.

72890

a-Torsional Damper Remover and Installer (J-6978-E)

Installation

IMPORTANT: The inertia weight section of torsional damper is assembled to the hub

with a rubber type material. The installation procedure (with proper tool) must be

followed or movement of the inertia weight on the hub will destroy the tuning of the

torsional damper.

1. Replace key in crankshaft if it is damaged.

2. Coat seal surface of torsional damper with engine oil.

NOTE: If a suitable torsional damper installer installation tool is not available, use a block

of wood as a driver. Be very careful not to cause pulley or weight to shift on their rubber

mounts.

3. Install torsional damper on crankshaft, using torsional damper remover and installer as

follows:

a. Install appropriate end of threaded rod into crankshaft.

IMPORTANT: Be sure to install threaded rod in crankshaft at least 1/2 in. (13 mm) to

prevent damage to threads.

b. Install plate, thrust bearing, washer and nut on rod.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-38 90-861329--1 MARCH 1999

c. Install torsional damper on crankshaft by turning nut until it contacts.

74529

a-Torsional Damper Remover and Installer (J-23523-E)

d. Remove tool from crankshaft.

e. To prevent oil leakage, apply Quicksilver RTV sealant to torsional damper keyway.

f. Install torsional damper bolt. Torque to 70 lb-ft (95 Nm).

4. Install drive pulley(s). Torque bolts to 35 lb-ft (48 Nm).

5. Install and adjust drive belts.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-39

Crankcase Oil Seal

Replacing Oil Seal Without Removing Front Cover

REMOVAL

1. Remove torsional damper.

2. Pry seal out of cover from the front with a large screwdriver. Be careful not to distort front

cover or damage crankshaft.

INSTALLATION

IMPORTANT: Correct rotation oil seal must be used to prevent oil leak.

1. Apply Quicksilver Perfect Seal to seal retainer mating surface and apply grease to seal

lips.

2. Install new seal with open end of seal inward, using crankcase front cover seal installer.

Drive seal in until it contacts. Do not use excessive force.

74531

a-Key In Crankshaft

b-Lobe of Bore Clears Key

3. Reinstall torsional damper as outlined.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-40 90-861329--1 MARCH 1999

Crankcase Front Cover

Removal

1. Remove engine from boat if necessary to gain access to cover.

2. Remove torsional damper and oil pan.

3. Remove water circulating pump.

4. Remove crankcase front cover.

5. If damaged, drive oil seal out of front cover (from the rear) using a punch.

Cleaning and Inspection

Clean front cover in solvent and dry with compressed air. Clean old gasket material and

sealer from mating surfaces on cover and cylinder block. Check gasket surface on front

cover for distortion, and fix if necessary. Surfaces must be clean and flat or oil leakage may

result.

Installation

1. Install oil seal in cover with lip of seal toward inside of engine, using crankcase front

cover seal installer. Support cover around seal area with appropriate tool as shown.

74530

a-Crankcase Front Cover Seal Installer (J-35468)

2. Coat both sides of front cover gasket with Quicksilver Perfect Seal and place in position

on engine.

3. Install front cover. Ensure holes in cover align with dowel pins in block. Torque front

cover attaching screws to 100 lb-in. (11 Nm).

4. Install oil pan and torsional damper as outlined.

5. Install water circulating pump.

6. Reinstall engine in boat.

7. Fill crankcase with engine oil.

CAUTION

Ensure that cooling water supply is available before starting the engine.

8. Start engine and check for water and oil leaks.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-41

Flywheel and Engine Coupler

Removal

1. Remove engine from boat. Refer to SECTION 2 “Removal and Installation.”

2. Refer to “Flywheel Housing” description in this section and remove flywheel housing and

related parts.

72318

a-Flywheel Housing

b-Cover

c-Press Mount Out with Press

3. Remove MCM coupler.

4. Remove flywheel.

72349

Alpha One Coupler

Inspection

1. Inspect splines in coupler for wear.

2. Check flywheel ring gear for worn and missing teeth.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-42 90-861329--1 MARCH 1999

Installation

1. Clean mating surfaces of flywheel and crankshaft. Remove any burrs. Mating surfaces

must be clean bare metal.

2. Align dowel hole in flywheel with dowel in crankshaft.

3. Install flywheel.

4. Torque bolts to 75lb-ft (100Nm).

5. Check flywheel runout as follows:

a. Attach a dial indicator to engine block.

b. Take readings around outer edge of flywheel. Push in on flywheel to remove crank-

shaft end play. Maximum runout - .008 in. (0.203 mm).

72353

a-.008 in. (0.203 mm) Maximum Runout

b-Push Flywheel And Crankshaft Forward As Far As It Will Go When Taking

Reading

6. Insert three rubber bumpers in Alpha coupler before installation on flywheel.

72354

a-Rubber Bumper

7. Install drive coupler. If reusing screws, use Loctite 27131.

8. Torque bolts to 35 lb-ft (48 Nm).

9. Install flywheel housing and related parts. Torque bolts to 30 lb-ft (41 Nm).

10. Install flywheel housing cover. Torque bolts to 80 lb-in. (9 Nm).

11. Refer to SECTION 2 “Removal and Installation” and install engine.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-43

Rear Main Oil Seal

The rear crankshaft oil seal can be replaced without removing the oil pan or rear main

bearing cap from engine.

Removal

1. Remove seal by using a screwdriver to pry it out of retainer as shown.

72355

a-Rear Seal

b-Seal Retainer

c-Slots (Three)

Cleaning and Inspection

1. Clean crankshaft/seal running surface and seal retainer.

2. Clean gasket material from mating surfaces.

3. Inspect oil seal retainer for cracks or scored surface.

4. Inspect oil seal for worn, dry or torn rubber. Replace if necessary (refer to “Rear Main

Oil Seal” as outlined).

5. Inspect alignment pin for damage; replace if necessary.

IMPORTANT: Correct rotation oil seal must be used to prevent oil leak.

Installation

1. Apply Quicksilver Perfect Seal to seal retainer mating surface. Apply grease to seal lips.

2. Install seal using rear main seal installer.

72356

a-Rear Main Seal Installer (J-26817-A)

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-44 90-861329--1 MARCH 1999

3. Coat seal lips with clean motor oil.

4. Install gasket and oil seal retainer with rear main seal.

5. Coat threads of oil seal retainer fasteners with Loctite Pipe Sealant with Teflon.

6. Install oil seal retainer fasteners and torque to 133 lb-in. (15 Nm).

7. Install oil pan fasteners. Torque 1/4-20 threaded fasteners to 80 lb-in. (9 Nm) and

5/16-18 threaded fasteners to 165 lb-in. (19 Nm).

NOTE: The oil pan gasket may be re-used if it is still pliable and is not cracked, torn or other-

wise damaged.

Main Bearings

IMPORTANT: Before removing main bearing caps or connecting rod caps, mark them

for reassembly in their original locations.

Main bearings are the precision insert type and do not use shims for adjustment. If

clearances are found to be excessive, a new bearing, both upper and lower halves, will be

required. Service bearings are available in standard size and .001 in., .010 in. and .020 in.

undersize.

Selective fitting of both rod and main bearing inserts is necessary in production in order to

obtain close tolerances. For this reason you may find one-half of a standard insert with one-

half of a .001 in. undersize insert which will decrease the clearance .0005 in. from using a

full standard bearing.

When a production crankshaft cannot be precision fitted by this method, it then is ground

.009 in. undersize on main journals only. A .009 in undersize bearing and .010 in. undersize

bearing may be used for precision fitting in same manner as previously described. Any

engine fitted with a .009 in. undersize crankshaft will be identified by the following markings:

• “.009” will be stamped on crankshaft counterweight forward of center main journal.

• No. “9” will be stamped on block at left front oil pan rail.

IMPORTANT: If crankshaft has an undersize journal and a new bearing is required,

journal must be reconditioned to accept a .010 or .020 in. undersize bearing as .009

in. undersize bearings are not available for service.

Inspection

In general, the lower half of the bearing (except No. 1 bearing) shows greater wear and more

distress from fatigue. If, upon inspection, the lower half is suitable for use, it can be assumed

that the upper half is also satisfactory. If the lower half shows evidence of wear or damage,

both upper and lower halves should be replaced. Never replace one half without replacing

the other half.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-45

Checking Clearances

To obtain accurate measurements while using Plastigage, or its equivalent, engine must be

out of the boat and upside down so crankshaft will rest on the upper bearings and total clear-

ance can be measured between lower bearing and journal.

To ensure the proper seating of the crankshaft, all bearing cap bolts should be at their speci-

fied torque. In addition, prior to checking fit of bearings, the surface of the crankshaft journal

and bearing should be wiped clean of oil.

1. With the oil pan and oil pump removed, remove bearing cap and wipe oil from journal

and bearing cap to be inspected.

2. Place a piece of gauging plastic the full width of the bearing (parallel to the crankshaft)

on the journal as shown.

72558

a-Gauging Plastic

b-Journal

3. Install the bearing cap and evenly torque the retaining bolts to specifications. Bearing

cap MUST be torqued to specification in order to ensure proper reading. Variations in

torque affect the compression of the plastic gauge.

IMPORTANT: Do not rotate the crankshaft while the gauging plastic is between the

bearing and journal.

4. Remove bearing cap. The flattened gauging plastic will be found adhering to either the

bearing cap or journal.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-46 90-861329--1 MARCH 1999

5. On the edge of the gauging plastic envelope there is a graduated scale which is corre-

lated in thousandths of an inch. Without removing the gauging plastic, measure its com-

pressed width (at the widest point) with the graduations on the gauging plastic envelope

as shown.

72358

a-Compressed Gauging Plastic

b-Graduated Scale

NOTE: Normally main bearing journals wear evenly and are not out of round. However, if

a bearing is being fitted to an out-of-round journal (.001 in. max.), be sure to fit to the

maximum diameter of the journal. If the bearing is fitted to the minimum diameter and the

journal is out of round .001 in., interference between the bearing and journal will result in

rapid bearing failure. If the flattened gauging plastic tapers toward the middle or ends, there

is a difference in clearance indicating taper, low spot or other irregularity of the bearing or

journal. Be sure to measure the journal with a micrometer if the flattened gauging plastic

indicates more than .001 in. difference.

6. If the bearing clearance is within specifications, the bearing insert is satisfactory. If the

clearance is not within specifications, replace the insert. Always replace both upper and

lower inserts as a unit.

7. A standard, or .001 in., undersize bearing may produce the proper clearance. If not, it

will be necessary to regrind the crankshaft journal for use with the next undersize

bearing.

8. After selecting new bearing, recheck clearance.

9. Proceed to the next bearing. After all bearings have been checked, rotate the crankshaft

to see that there is no excessive drag. When checking No. 1 main bearing, loosen acces-

sory drive belts so as to prevent tapered reading with plastic gauge.

Main Bearing Replacement

1. Remove and inspect crankshaft.

2. Remove main bearings from cylinder block and main bearing caps.

3. Coat bearing surfaces of new, correct-size, main bearing with oil and install in cylinder

block and main bearing caps. Check clearance.

4. Install crankshaft.

5. Torque all main bearing caps, EXCEPT THE REAR MAIN CAP, to 75 lb-ft (102 Nm).

6. Torque rear main bearing cap to 10-12 lb-ft (14-16 Nm); then tap end of crankshaft, first

rearward then forward with a lead hammer. This will line up rear main bearing and crank-

shaft thrust surfaces. Torque rear main bearing cap to 75 lb-ft (102 Nm).

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-47

Connecting Rod Bearings

Connecting rod bearings are of the precision insert type and do not use shims for adjust-

ment. DO NOT FILE RODS OR ROD CAPS. If clearances are found to be excessive, a new

bearing will be required. Service bearings are available in standard size and .001 in. and

.002 in. undersize for use with new and used standard size crankshafts, and in .010 in. and

.020 in. undersize for use with reconditioned crankshafts.

On removing a connecting rod cap, it is possible to find a .010 in. undersize bearing. These

are used in manufacturing for selective fitting.

Inspection and Replacement

IMPORTANT: Before you remove the connecting rod cap, mark the side of the rod and

cap with the cylinder number to assure matched reassembly of rod and cap.

1. Remove connecting rod cap and bearing.

2. Inspect bearing for evidence of wear or damage. Defective bearings should not be

installed. Typical bearing failures are shown under “General.”

3. Wipe bearings and crankshaft clean of oil.

4. Measure crankpin for out-of-round of taper with a micrometer. If not within specifica-

tions, replace or recondition crankshaft. If within specifications and new bearing is to be

installed, measure maximum diameter of crankpin to determine new bearing size

required.

5. If within specifications, measure new or used bearing clearances with gauging plastic.

IMPORTANT: If bearing is fitted to out-of-round crankpin, br sure to fit maximum

diameter of crankpin. If bearing is fitted to minimum diameter, and crankpin is

out-of-round .001 (0.02 mm), interference between bearing and crankpin will result

in rapid bearing failure.

a. Place a piece of gauging plastic the full width of crankpin (parallel to crankshaft).

b. Install bearing connecting rod and cap.

c. Place a piece of gauging plastic the length of the bearing (parallel to the crankshaft)

on the crankpin or bearing surface as shown. Position the gauging plastic in the

middle of the bearing shell. Bearings are eccentric and false readings could occur

if placed elsewhere.

72361

a-Gauging Plastic

d. Install the bearing in the connecting rod and cap.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-48 90-861329--1 MARCH 1999

e. Install the bearing cap and torque nuts to 45 lb-ft (61 Nm).

IMPORTANT: Do not turn the crankshaft with the gauging plastic installed.

f. Remove the bearing cap and using the scale on the gauging plastic envelope, mea-

sure the gauging plastic width at the widest point as shown.

72362

6. If the clearance exceeds specifications, select a new, correct size bearing and measure

the clearance.

Be sure to check what size bearing is being removed in order to determine proper replace-

ment size bearing. If clearance cannot be brought to within specifications, the crankpin will

have to be ground undersize. If the crankpin is already at maximum undersize, replace

crankshaft.

7. Coat the bearing surface with oil, install the rod cap and torque nuts to 45 lb-ft (61 Nm).

8. When all connecting rod bearings have been installed, tap each rod lightly (parallel to

the crankpin) to make sure they have clearance.

9. Measure all connecting rod side clearances between connecting rod caps as shown -

.006-.014 in. (0.16-0.35 mm).

72891

a-Take Measurement Here

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-49

Connecting Rod/Piston Assembly

Removal

1. With oil pan, oil pump and cylinder head removed, use a ridge reamer to remove any

ridge and/or deposits from upper end of cylinder bore.

IMPORTANT: Before ridge and/or deposits are removed, turn crankshaft until piston

is at bottom of stroke and place a cloth on top of piston to collect cuttings. After ridge

and/or deposits are removed, turn crankshaft until piston is at top of stroke, then

remove cloth and cuttings.

2. Inspect and mark connecting rods and bearing caps.

3. Remove connecting rod cap and install connecting rod bolt guide (3/8-24) on bolts. Push

connecting rod and piston assembly out of top of cylinder block.

NOTE: It will be necessary to turn crankshaft slightly to disconnect and remove some con-

necting rod and piston assemblies.

72892

a-Connecting Rod Bolt Guide (3/8-24) (J-5239)

Disassembly

1. Disassemble piston from connecting rod using piston pin remover as shown.

72365

a-Piston Pin Remover (J-24086-B)

b-Arched Base

c-Piston

d-Connecting Rod

e-Rod Support

2. Position connecting rod on tool rod support with rod support inserted between

connecting rod end and piston. Align piston pin with hole located in top of arched base.

3. Insert pin remover through hole (located in top of arched base) and into piston pin hole.

Press on pin remover to remove piston pin.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-50 90-861329--1 MARCH 1999

Cleaning and Inspection

CONNECTING RODS

1. Wash connecting rods in cleaning solvent and dry with compressed air.

2. Check for twisted and bent rods and inspect for nicks and cracks. Replace damaged

connecting rods.

PISTONS

NOTE: Cylinder bore and taper must be within specifications before pistons can be consid-

ered for reuse.

1. Clean varnish from piston skirts with a cleaning solvent. DO NOT WIRE BRUSH ANY

PART OF PISTON. Clean ring grooves with a groove cleaner and make sure oil ring

holes are clean.

2. Inspect piston for cracked ring lands, skirts and pin bosses, wavy worn ring lands,

scuffed or damaged skirts and eroded areas at top of piston. Replace pistons that are

damaged or show signs of excessive wear.

3. Inspect grooves for nicks and burrs that might cause rings to hang up.

4. Measure piston skirt (across centerline of piston pin) and check clearance as outlined

under “Cylinder Block.”

5. Slip outer surface of a new top and second compression ring into respective piston ring

groove and roll ring entirely around the groove to ensure that ring is free as shown. If

binding occurs at any point, determine cause. If caused by ring groove, remove by dres-

sing with a fine cut file. If binding is caused by a distorted ring, recheck with another ring.

72894

6. Proper clearance of piston ring in its piston ring groove is very important to provide

proper ring action and reduce wear. When fitting new rings, clearances between ring

and groove surfaces should be measured. See “Specifications.”

72895

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-51

PISTON PINS

1. Piston pin clearance is designed to maintain adequate clearance under all engine

operating conditions. Because of this, piston and piston pin are a matched set and not

serviced separately.

2. Inspect piston pin bores and piston pins for wear. Piston pin bores and piston pins must

be free of varnish and scuffing when measured. Measure piston pin with a micrometer

and piston pin bore with a dial bore gauge or inside micrometer. If clearance is in excess

of the .001 in. (0.02 mm) wear limit, replace piston and piston pin assembly.

Reassembly

PISTONS AND PISTON PINS

IMPORTANT: When reassembling pistons and connecting rods, the following must

be kept in mind.

• Piston and pin are machine fitted to each other and must remain together as a

matched set. Do not intermix pistons and pins.

• If original pistons and/or connecting rods are being used, be sure to assemble

pistons and connecting rods so they can be reinstalled in same cylinder from

which they were removed.

• Connecting rod bearing tangs are always toward outside of cylinder block.

72368

a-Rod Bearing Tangs

• Notch on piston must be positioned toward the front of the engine.

72896

a-Notch

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-52 90-861329--1 MARCH 1999

1. Assemble piston to connecting rod using piston pin remover as shown. Follow instruc-

tions supplied with tool.

72371

a-Piston Pin Remover (J-24086-B)

2. Once assembled, check piston for freedom of movement (back and forth and up and

down) on connecting rod. Piston should move freely in all directions. If it does not, piston

pin bore is tight and piston/pin assembly must be replaced.

3. If a new connecting rod has been installed, mark connecting rod and cap (on side of rod

and cap with slots for connecting rod bearing tangs) with cylinder number in which it will

be installed.

PISTON RINGS

All compression rings are marked on upper side of ring. When installing compression rings,

make sure that marked side is toward top of piston. The top ring is treated with molybdenum

for maximum life. Oil control rings are a three piece type, consisting of 2 segments (rails)

and a spacer.

Oil control rings are a three-piece type, consisting of two rings and a spacer.

1. Select rings comparable in size to cylinder bore and piston size.

2. Slip compression ring in cylinder bore, then press ring down into cylinder bore about 1/4

in. (6 mm) (below ring travel). Be sure that ring is square with cylinder wall.

3. Measure gap between ends of ring with a feeler gauge as shown.

72372

4. If gap between ends of ring is below specifications, remove ring and try another for fit.

5. Fit each compression ring to cylinder in which it is going to be used.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-53

6. Clean and inspect pistons, if not previously done.

7. Install piston rings as follows:

a. Install oil ring spacer in groove and insert anti- rotation tang in oil hole.

b. Hold spacer ends butted and install lower steel oil ring rail with gap properly located.

c. Install upper steel oil ring rail with gap properly located.

d. Flex the oil ring assembly to make sure ring is free. If binding occurs at any point,

the cause should be determined and, if caused by ring groove, removed by dressing

groove with a fine cut file. If binding is caused by a distorted ring, use a new ring.

IMPORTANT: Use piston ring expander (91-24697) for compression ring installation.

e. Install lower compression ring with marked side up, using ring expander.

f. Install top compression ring with marked side up, using ring expander.

Installation

IMPORTANT: Cylinder bores must be clean before piston installation. Clean with a

light honing, as necessary. Then clean with hot water and detergent wash. After

cleaning, swab bores several times with light engine oil and clean cloth, then wipe

with a clean dry cloth.

1. Lubricate connecting rod bearings and install in rods and rod caps.

2. Lightly coat pistons, rings and cylinder walls with light engine oil.

3. With bearing caps removed, install connecting rod bolt guide (3/8-24) (J-5239) on

connecting rod bolts.

IMPORTANT: Be sure ring gaps are properly positioned as shown.

72373

Ring Gap Location

a-Oil Ring Spacer Gap (Tang In Hole Or Slot Within Arc)

b-Oil Ring Gaps

c-2nd Compression Ring Gap

d-Top Compression Ring Gap

e-Port Side

f-Engine Front

g-Starboard Side

4. Install each connecting rod and piston assembly in its respective bore.

a. Install with connecting rod bearing tangs toward outside of cylinder block.

b. Use piston ring compressor to compress rings.

c. Guide connecting rod into place on crankshaft journal with connecting rod bolt guide.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-54 90-861329--1 MARCH 1999

d. Use a hammer handle with light blows to install piston into bore.

e. Hold ring compressor firmly against cylinder block until all piston rings have entered

cylinder bore.

IMPORTANT: Be sure to install new pistons in same cylinders for which they were

fitted, and used pistons in same cylinder from which they were removed. Each

connecting rod and bearing cap should be marked, beginning at front of engine.

Numbers on connecting rod and bearing cap must be on same side when installed

in cylinder bore. If a connecting rod is ever transposed from one block or cylinder to

another, new bearings should be fitted and connecting rod should be numbered to

correspond with new cylinder number.

72898

a-Piston Ring Compressor (J-8037)

5. Remove connecting rod bolt guide.

6. Install bearing caps and torque nuts to 45 lb-ft (27 Nm).

7. Check connecting rod side clearance as previously described.

NOTE: If bearing replacement is required, refer to “Connecting Rod Bearings.”

8. Install as previously outlined:

a. Oil pump.

b. Dipstick and oil pan.

c. Cylinder heads.

d. Intake manifold.

e. Distributor.

9. Torque rocker arm nuts to 20 lb-ft (27 Nm).

10. Install rocker arm cover and torque to 40 lb-in (4.5 Nm)

11. Fill crankcase with oil. Refer to SECTION 1B “Maintenance.”

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-55

Crankshaft

Removal

1. Remove engine from boat.

2. Drain crankcase oil.

3. Remove as outlined:

a. Starter.

b. Flywheel housing.

c. Drive coupler and flywheel.

d. Belts.

e. Water pump.

f. Crankshaft pulley and torsional damper.

g. Spark plugs.

h. Oil pan and dipstick tube.

i. Oil pump.

j. Timing chain cover.

4. Turn crankshaft to align timing mark with camshaft mark.

5. Remove camshaft sprocket.

6. Remove rear main seal and retainer.

7. Ensure all bearing caps (main and connecting rods) are marked so they can be rein-

stalled in their original locations.

8. Remove connecting rod bearing caps, then push piston and rod assemblies toward

heads.

9. Remove main bearing caps and carefully lift crankshaft out of cylinder block.

10. Remove crankshaft gear as shown.

74476

11. If new main and/or connecting rod bearings are to be installed, remove main bearing

inserts from cylinder block and bearing caps, and/or connecting rod bearing inserts from

connecting rod and caps. Install new bearings following procedures outlined.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-56 90-861329--1 MARCH 1999

Cleaning and Inspection

1. Wash crankshaft in solvent and dry with compressed air.

2. Measure main bearing journals and crankpin dimensions with a micrometer for

out-of-round, taper or undersize (see “Specifications”).

3. Check crankshaft for runout (by supporting at front and rear main bearings journals in

V-blocks) and check at front and rear intermediate journals with a dial indicator (see

“Specifications”).

4. Replace or recondition crankshaft if not within specifications.

Installation

1. If a new crankshaft is being installed, remove timing sprocket from old crankshaft and

reinstall on new crankshaft as outlined.

IMPORTANT: Be sure that all bearings and crankshaft journals are clean.

2. Install main bearings in engine block as shown.

72359

Main Bearing Inserts

a-Lower Bearing Insert

b-Upper Bearing Insert

c-Oil Groove

3. Carefully lower crankshaft into place. Be careful not to damage bearing surface.

4. Check clearance of each main bearing, following procedure outlined under “Main Bear-

ings.” If bearing clearances are satisfactory, apply engine oil to journals and bearings.

5. Install main bearing caps. Torque bolts to 75 lb-ft (102 Nm). When tightening rear main

bearing cap, follow procedure outlined under “Main Bearings.”

6. Check crankshaft end play as previously outlined.

7. Install rear main seal retainer and seal. Torque fasteners to 133 lb-in. (15 Nm).

8. Check clearance for each connecting rod bearing, following procedure under “Connect-

ing Rod Bearings.” If bearing clearances are satisfactory, apply engine oil to journals and

bearings.

9. Install rod caps and torque nuts to 45 lb-ft (61 Nm).

10. Turn crankshaft so mark on timing sprocket is facing camshaft.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-57

11. Install as outlined:

a. Timing chain and sprocket on camshaft - align marks with crankshaft.

b. Timing chain cover.

c. Oil pump.

d. Dipstick tube and oil pan.

e. Spark plugs.

f. Torsional damper and crankshaft pulley.

g. Water pump.

h. Belts.

i. Flywheel and drive coupler.

j. Flywheel housing.

k. Starter.

12. Install new oil filter. Fill crankcase with oil.

Crankshaft Sprocket

Removal

1. Remove torsional damper and crankcase front cover as previously outlined.

2. Remove camshaft timing chain as outlined, and using crankshaft gear and sprocket

puller (J-5825-A), remove crankshaft sprocket.

Installation

1. Using crankshaft gear and sprocket installer, as shown, install sprocket on crankshaft.

72377

a-Crankshaft Gear and Sprocket Installer (J-5590)

2. Install timing chain as outlined.

3. Install crankcase cover and torsional damper as outlined.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-58 90-861329--1 MARCH 1999

Camshaft

Measuring Lobe Lift

NOTE: Procedure is similar to checking valve timing. If improper valve operation is indi-

cated, measure lift of each push rod in consecutive order and record readings.

1. Remove valve mechanism as previously outlined.

2. Position indicator with ball socket adaptor tool on push rod. Be sure that push rod is in

lifter socket.

72907

a-Ball Socket Adaptor Tool (J-8520-1)

3. Rotate crankshaft torsional damper slowly in direction of rotation until lifter is on heel of

cam lobe. At this point, push rod will be in its lowest position.

4. Set dial indicator on zero, then rotate balancer slowly (or attach an auxiliary starter

switch and “bump” engine over) until push rod is in fully raised position.

5. Compare total lift, recorded from dial indicator, with “Specifications.”

6. Continue to rotate engine until indicator reads zero. This will be a check on accuracy of

original indicator reading.

7. If camshaft readings for all lobes are within specifications, remove dial indicator assem-

bly.

8. Install rocker arm and push rod. Torque nuts to 20 lb-ft (27 Nm).

Removal

1. Remove valve lifters as previously outlined.

2. Remove crankcase front cover as previously outlined.

3. Remove fuel pump.

4. Align timing gear marks, then remove the two camshaft thrust plate screws by working

through holes in camshaft gear.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-59

5. Pull camshaft and gear assembly out through front of block.

IMPORTANT: Support camshaft carefully when removing to protect camshaft bear-

ings.

74438

a-Timing Marks

b-Screw Access Holes

Inspection

1. Measure camshaft bearing journals with a micrometer for out-of-round condition. If

journals exceed .001 in. (0.02 mm) out-of-round, camshaft should be replaced.

2. Also check camshaft for alignment with V-blocks and dial indicator which indicates exact

amount camshaft is out of true. If dial indicator reads more than .002 in. (0.05 mm)

camshaft should be replaced.

72909

Checking Camshaft Alignment

3. Inspect camshaft gear and thrust plate for wear or damage. Measure camshaft end play

.001 - .005 in. (0.03-0.1 mm).

74439

a-Feeler Gauge

b-Camshaft Gear

c-Camshaft Thrust Plate

d-Take Measurement Here

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-60 90-861329--1 MARCH 1999

Camshaft Gear Replacement

1. If inspection indicates that camshaft, gear or thrust plate should be replaced, remove

gear from camshaft.

2. Place camshaft through gear remover, place end of remover on table of a press shaft

out of gear.

CAUTION

Position thrust plate so that woodruff key in shaft does not damage plate when shaft

is pressed out of gear. Also support hub of gear, or gear will be seriously damaged.

74477

a-Camshaft Gear

b-Support Sleeve

c-Camshaft

Installation

1. Install camshaft and gear assembly in engine block. Be careful not to damage camshaft

bearings or camshaft.

74438

a-Timing Marks

b-Screw Access Holes

2. Turn crankshaft and camshaft so the timing marks on gear teeth will line up. Push

camshaft thrust plate to block screws and torque to specifications.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-61

3. Check camshaft and crankshaft gear run-out with a dial indicator. Camshaft gear run-out

should not exceed .004 in. (0.1 mm) and crankshaft gear run-out should not exceed .003

in. (0.07 mm).

74440

Checking Timing Gear Run-Out

4. If gear run-out is excessive, remove gear and clean burrs from shaft or replace gear.

5. Check backlash between timing gear teeth with a dial indicator. Backlash should not be

less than .004 in. (0.010 mm) or more than .006 in. (0.15 mm).

74441

Checking Timing Gear Backlash

6. Install fuel pump.

7. Install front crankcase cover.

8. Pour GM engine oil supplement or light engine oil over camshaft lobes and install valve

lifters.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-62 90-861329--1 MARCH 1999

Camshaft Bearings

Removal

Camshaft bearings can be replaced while engine is disassembled for overhaul or without

complete disassembly. To replace bearings without complete disassembly, remove cam-

shaft and crankshaft, leaving cylinder heads attached and pistons in place. Before removing

crankshaft, fasten connecting rods against sides of engine so that they will not interfere

while replacing camshaft bearings.

1. With camshaft and crankshaft removed, drive camshaft rear plug from cylinder block.

NOTE: This procedure is based on removal of bearings from center of engine first, thus

requiring a minimum amount of turns to remove all bearings.

2. Using camshaft bearing remover and installer set (J-6098-01) (with nut and thrust

washer installed to end of threads), position pilot in front camshaft bearing and install

puller screw through pilot.

3. Install tool with shoulder toward bearing. Be sure a sufficient amount of threads are

engaged.

4. Using two wrenches, hold puller screw while turning nut. When bearing has been pulled

from bore, remove tool and bearing from puller screw.

74478

5. Remove remaining bearings (except front and rear) in same manner. It will be necessary

to position pilot in rear camshaft bearing to remove rear intermediate bearing.

74479

6. Assemble driver on driver handle and remove front and rear camshaft bearings by

driving toward center of cylinder block.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-63

Inspection

Clean camshaft bearing bores in cylinder block with solvent and blow out with compressed

air. Be sure grooves and drilled oil passages are clean.

Installation

CAUTION

Oil holes in bearings must line up with oil holes in cylinder block. Oil hole is on top

side of bearing shell and cannot be seen during installation, so first align bearing

shell oil hole with oil hole in bore and mark opposite side of bearing and block at

bore to easily position oil hole during installation.

IMPORTANT: Front bearing must be driven approximately .125 in. (3 mm) behind the

block face to uncover oil hole to timing gear oil nozzle.

IMPORTANT: All camshaft bearings are not the same. Be sure to install bearings in

proper locations (Indicated by bearing manufacturer) and to position bearings as

follows (directional references are in reference to engine in its normal operating

position):

Lubricate outer surface of new camshaft bearings with engine oil to ease installation.

1. Installing intermediate and center bearings:

a. Install nut and thrust washer all the way onto puller screw, then position pilot in front

camshaft bearing bore and insert screw through pilot.

b. Index center camshaft bearing, then position appropriate size remover and installer

tool in bearing and thread puller screw into tool. Be sure at least 1/2 in. (13 mm) of

threads are engaged.

74478

Pulling Cam Bearing From Bore

c. Using two wrenches, hold puller screw and turn nut until bearing has been pulled into

position. Remove the remover and installer tool and ensure that oil hole(s) in bearing

is positioned correctly.

d. Install intermediate bearings in same manner. Be sure to index bearings correctly.

It will be necessary to position pilot in rear camshaft bearing bore to install rear inter-

mediate bearing.

2. Installing front and rear bearings:

a. Install appropriate size remover and installer tool on drive handle.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-64 90-861329--1 MARCH 1999

b. Index front bearing (as explained in “Important” above), and drive it into position with

tool. Check position of oil hole(s) in bearing to ensure bearing is positioned correctly.

74479

Removal And Installation Camshaft Bearings

a-Installation Tool

b-Camshaft Bearing

c. Install rear bearing in same manner. Be sure to index bearing correctly.

3. Install a new camshaft rear plug.

IMPORTANT: Plug must be installed flush to 1/32 in. (0.8 mm) deep and must be paral-

lel with rear surface of cylinder block.

4. Install crankshaft and camshaft as previously outlined.

Cylinder Block

Cleaning and Inspection

1. Remove all engine components as previously outlined.

2. Wash cylinder block thoroughly in cleaning solvent and clean all gasket surfaces.

3. Remove oil gallery plugs and clean all oil passages.

4. Remove expansion plugs.

NOTE: These plugs may be removed with a sharp punch or they may be drilled and pried

out.

5. Clean and inspect water passages in cylinder block.

6. Inspect cylinder block for cracks in cylinder walls, water jacket valve lifter bores and main

bearing webs.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-65

7. Measure cylinder bores to ensure they meet specifications.

CAUTION

Measure cylinder walls for taper, out-of-round or excessive ridge at top of ring

travel. This should be done with a dial indicator or inside micrometer. Carefully

work gauge up and down cylinder to determine taper and turn it to different points

around cylinder wall to determine out-of-round condition. If cylinders exceed

specifications, boring and/or honing will be necessary.

72385

Cylinder Measurement

a-At right angle to centerline of engine

b-Parallel to centerline of engine

“Out-of-Round” = Difference between “A” and “B”

“Taper” =Difference between measurement “A” at top of cylinder bore and “A” measurement

at bottom of cylinder bore

72386

Measuring Cylinder Bore With Snap Gauge

72387

Measuring Cylinder Bore With Dial Indicator

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-66 90-861329--1 MARCH 1999

8. Check cylinder head gasket surfaces for warp with a machinist’s straight-edge and a

feeler gauge, as shown. Take measurements diagonally across surfaces (both ways)

and straight down center. If surfaces are warped more than .003 in. (0.07 mm) in a 6 in.

area or .007 in. (0.2 mm) overall, block must be resurfaced by an automotive machine

shop.

72910

a-Machinist’s Straight-Edge

b-Feeler Gauge

CYLINDER CONDITIONING

1. Performance of the following operation depends upon engine condition at time of repair.

2. If cylinder block inspection indicates that block is suitable for continued use (except for

out-of-round or tapered cylinders), they can be conditioned by honing or boring.

3. If cylinders have less than .005 in. (0.127 mm) taper or wear, they can be conditioned

with a hone and fitted with high limit standard size piston. A cylinder bore of more than

.005 in. wear or taper may not clean up entirely when fitted to a high limit piston. To

entirely clean up the bore, it will be necessary to bore for an oversize piston. If more than

.005 in. taper or wear, bore and hone to smallest oversize that will permit complete

resurfacing of all cylinders.

4. When pistons are being fitted and honing is not necessary, cylinder bores may be

cleaned with a hot water and detergent wash. After cleaning, swab cylinder bores

several times with light engine oil and a clean cloth, then wipe with a clean dry cloth.

CYLINDER BORING

1. Before using any type boring bar, file off top of cylinder block to remove dirt or burrs. This

is very important to prevent boring bar tilt, resulting in the bored cylinder wall not being

at right angles to crankshaft.

2. Measure piston to be fitted with a micrometer, measuring at center of piston skirt and

at right angles to piston pin. Bore cylinder to same diameter as piston and hone to give

specified clearance.

NOTE: Hone cylinders as outlined under “Cylinder Honing” and “Piston Selection,”

following.

3. Carefully observe instructions furnished by manufacturer of equipment being used.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-67

CYLINDER HONING

1. Follow hone manufacturer’s recommendations for use of hone and cleaning and lubrica-

tion during honing.

2. Occasionally, during the honing operation, thoroughly clean cylinder bore and check

piston for correct fit in cylinder.

3. When finish-honing a cylinder bore to fit a piston, move hone up and down at a sufficient

speed to obtain very fine uniform surface finish marks in a crosshatch pattern of approxi-

mately 30 degrees to cylinder bore. Finish marks should be clean but not sharp, free

from imbedded particles and torn or folded metal.

4. Permanently mark piston (for cylinder to which it has been fitted) and proceed to hone

cylinders and fit remaining pistons.

IMPORTANT: Handle pistons with care and do not attempt to force them through cyl-

inder until cylinder is honed to correct size, as this type piston can be distorted by

careless handling.

5. Thoroughly clean cylinder bores with hot water and detergent. Scrub well with a stiff

bristle brush and rinse thoroughly with hot water. It is extremely essential that a good

cleaning operation be performed. If any abrasive material remains in cylinder bores, it

will rapidly wear new rings and cylinder bores in addition to bearings lubricated by the

contaminated oil. Swab bores several times with light engine oil on a clean cloth, then

wipe with a clean dry cloth. Cylinder should not be cleaned with kerosene or gasoline.

Clean remainder of cylinder block to remove excess material spread during honing

operation.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-68 90-861329--1 MARCH 1999

PISTON SELECTION

1. Check used piston to cylinder bore clearance as follows:

a. Measure cylinder bore diameter with a snap gauge 2-1/2 in. (64 mm) from top of cyl-

inder bore as follows.

72386

b. Measure piston diameter at skirt across center line of piston pin as shown.

72911

c. Subtract piston diameter from cylinder bore diameter to determine piston-to-bore

clearance.

d. Determine if piston-to-bore clearance is in acceptable range shown in “Specifica-

tions.”

2. If used piston is not satisfactory, determine if a new piston can be selected to fit cylinder

bore within acceptable range.

3. If cylinder bore must be reconditioned, measure new piston diameter (across centerline

of piston pin), then hone cylinder bore to correct clearance (preferable range).

4. Mark piston to identify cylinder for which it was fitted.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-69

Oil Filter By-Pass Valve

Inspection and/or Replacement

With oil filter removed, check spring and fiber valve for operation. Inspect for a cracked or

broken valve. If replacement is necessary, pry valve out with screwdriver. Install and seat

a new valve by tapping in place with a 9/16 in. thin wall deep socket.

Refer to “Engine Parts List” when ordering parts for oil filter by-pass valve.

1. Remove oil filter from cylinder block and remove by-pass valve.

2. Clean by-pass valve in solvent and blow dry with compressed air.

3. Inspect fiber valve for cracks or other damage. Check that valve fits tightly against its

seat. Push valve down and release it. Valve should return freely to its seat. If valve

operation is questionable, by-pass valve should be replaced.

72912

Typical By-Pass Valve

a-Fiber Valve (Ensure Valve Fits Tightly Against the Seal)

4. Wipe out valve chamber in cylinder block to remove any foreign material.

5. Install by-pass valve or cylinder block adaptor to engine block.

6. Lubricate oil filter rubber seal and install hand-tight only.

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-70 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 3A-71

THIS PAGE IS INTENTIONALLY BLANK

Index

181 CID (3.0L) 4 CYLINDER GM ENGINE SERVICE MANUAL NUMBER 26

Page 3A-72 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-1

ELECTRICAL SYSTEM

Section 4A - Starting System

Table of Contents

Identification 4A-2. . . . . . . . . . . . . . . . . . . . . . . . . .

Replacement Parts Warning 4A-2. . . . . . . . . . . .

Battery 4A-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Battery Cable Recommendations 4A-3. . . . .

Starting System Components 4A-4. . . . . . . . . . .

Replacement Parts Warning 4A-5. . . . . . . . . . . .

Maintenance 4A-5. . . . . . . . . . . . . . . . . . . . . . .

Storage 4A-6. . . . . . . . . . . . . . . . . . . . . . . . . . .

Testing 4A-7. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Positive Current Flow 4A-8. . . . . . . . . . . . . . . . . .

Charging Guide 4A-9. . . . . . . . . . . . . . . . . . . . . . .

12 Volt Battery Recommended Rate*

and Time for Fully Discharged

Condition 4A-9. . . . . . . . . . . . . . . . . . . . . . . . .

Slave Solenoid Identification 4A-10. . . . . . . . . . .

Types 4A-10. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Standard Type Slave Solenoid 4A-10. . . . . .

Switch Type Slave Solenoid 4A-10. . . . . . . . .

Testing/Replacement 4A-11. . . . . . . . . . . . . . .

Solenoid Switch 4A-11. . . . . . . . . . . . . . . . . . . . . .

Periodic Inspection 4A-11. . . . . . . . . . . . . . . . . . .

PG260 Starter Motor 4A-12. . . . . . . . . . . . . . . . . .

PG260 Specifications 4A-12. . . . . . . . . . . . . .

Torque Specification 4A-12. . . . . . . . . . . . . . .

Description 4A-12. . . . . . . . . . . . . . . . . . . . . . .

PG260 Exploded View 4A-13. . . . . . . . . . . . .

Starter Motor Repair 4A-14. . . . . . . . . . . . . . . . . .

Removal 4A-14. . . . . . . . . . . . . . . . . . . . . . . . .

Disassembly 4A-14. . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 4A-18. . . . . . . . . . . .

Armature Tests 4A-19. . . . . . . . . . . . . . . . . . . .

Armature Bearing (Commutator End) 4A-20.

Gear Bearing 4A-20. . . . . . . . . . . . . . . . . . . . .

Shaft Assembly Bearing 4A-21. . . . . . . . . . . .

Drive End Housing Bearing 4A-21. . . . . . . . .

Brushes and Brush Holder 4A-22. . . . . . . . . .

Reassembly 4A-24. . . . . . . . . . . . . . . . . . . . . .

Starter Solenoid 4A-28. . . . . . . . . . . . . . . . . . . . . .

Testing/Replacement 4A-28. . . . . . . . . . . . . . .

Installation 4A-30. . . . . . . . . . . . . . . . . . . . . . . .

PG260F1 Starter Motor 4A-31. . . . . . . . . . . . . . .

PG260F1 Specifications 4A-31. . . . . . . . . . . .

Torque Specifications 4A-31. . . . . . . . . . . . . .

Lubricants/Sealants 4A-31. . . . . . . . . . . . . . . .

Description 4A-31. . . . . . . . . . . . . . . . . . . . . . .

Exploded View 4A-32. . . . . . . . . . . . . . . . . . . .

Starter Motor Repair 4A-33. . . . . . . . . . . . . . . . . .

Removal 4A-33. . . . . . . . . . . . . . . . . . . . . . . . .

Disassembly 4A-33. . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 4A-37. . . . . . . . . . . .

Armature Tests 4A-37. . . . . . . . . . . . . . . . . . . .

Reassembly 4A-38. . . . . . . . . . . . . . . . . . . . . .

Starter Solenoid 4A-42. . . . . . . . . . . . . . . . . . .

Installation 4A-44. . . . . . . . . . . . . . . . . . . . . . . .

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-2 90-861329--1 MARCH 1999

Identification

The starter identification number is located as shown.

72059

Delco PG 260 Starter Motor

a-Starter Identification Number

75820

Delco PG260F1 Starter Motor

NOTE: The RP long block, S/N 0L097000 and above, has 3 starter motor mounting holes

in the cylinder block. The RK long block, S/N 0L096999 and below, has 2 starter motor

mounting holes in the cylinder block.

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to

minimize risks of fire and explosion.

WARNING

Use of replacement electrical, ignition or fuel system components, which do not

comply with these rules and regulations, could result in a fire or explosion hazard

and should be avoided.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-3

Battery

Battery Cold Cranking Amperage

3.0L 375 cca, 475 mca, 90Ah

Battery Cable Recommendations

IMPORTANT: Terminals must be soldered to cable ends to ensure good electrical

contact. Use electrical grade (resin flux) solder only. Do not use acid flux solder, as

it may cause corrosion and failure.

Cable Length

Cable Gauge

Up to 3-1/2 ft (1.1 m) 4 (25 mm

)

3-1/2 - 6 ft (1.1-1.8 m) 2 (35 mm

)

6 - 7-1/2 ft (1.8-2.3 m) 1 (50 mm

)

7-1/2 - 9-1/2 ft (2.3-2.9 m) 0 (50 mm

)

9-1/2 - 12 ft (2.9-3.7 m) 00 (70 mm

)

12 - 15 ft (3.7-4.6 m) 000 (95 mm

)

15 - 19 ft (4.6-5.8 m) 0000 (120 mm

)

Both positive (+) and negative (–) cables

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-4 90-861329--1 MARCH 1999

Starting System Components

72929

a-Ignition Switch

b-Neutral Safety Switch

c-Starter Slave Solenoid

d-Circuit Breaker (not on all models)

e-Engine Ground Stud

f-Starter Solenoid

g-Wire Junction

h-20 Amp Fuse

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-5

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to mini-

mize risks of fire and explosion.

Use of replacement electrical, ignition or fuel system components that do not comply with

these rules and regulations could result in a fire or explosion hazard and should be avoided.

Maintenance

WARNING

Do not use jumper cables and a booster battery to start engine. Do not recharge a

weak battery in the boat. Remove battery and recharge in a ventilated area away

from fuel vapors, sparks or flames.

WARNING

Batteries contain acid which can cause severe burns. Avoid contact with skin, eyes

and clothing. Batteries also produce hydrogen and oxygen gases when being

charged. This explosive gas escapes fill/vent cell caps and may form an explosive

atmosphere around the battery for several hours after it has been charged; sparks

or flames can ignite the gas and cause an explosion that may shatter the battery and

could cause blindness or other serious injury.

Safety glasses and rubber gloves are recommended when handling batteries or

filling with electrolyte. Hydrogen gases that escape from the battery during

charging are explosive. When charging batteries, be sure battery compartment, or

area where battery is located, is well vented. Battery electrolyte is a corrosive acid

and should be handled with care. If electrolyte is spilled or splashed on any part of

the body, immediately flush the exposed area with liberal amounts of water and

obtain medical aid as soon as possible.

CAUTION

To prevent damage to the electrical system be sure to adhere to the following:

• When installing battery, be sure to connect the POSITIVE (+) battery cable to

POSITIVE (+) battery terminal first and then the NEGATIVE (–) battery cable to

NEGATIVE (–) battery terminal.

• Never disconnect the battery cables while the engine is running.

• If a charger or booster is to be used, be sure to connect it in parallel with existing

battery (positive to positive and negative to negative).

• When applying a booster charge to battery, disconnect both cables from battery

(to prevent damage to voltage regulator).

• Check battery condition periodically.

• Make sure that battery leads are kept clean and tight.

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-6 90-861329--1 MARCH 1999

1. Ensure that the battery meets the following certain conditions before testing:

CAUTION

Test battery in well ventilated area as gases given off by battery are hazardous.

• Battery must be 60 to 100°F (16 to 38°C).

• Electrolyte level must be correct in all cells.

• Battery must be at least half charged.

• No obvious defects.

2. Place battery under heavy load (as during engine cranking or with a variable resistor

tester) and test cell voltage while under load:

a. Check voltage per manufacturer’s specifications.

b. If readings are low, recharge and retest.

c. If readings remain low, battery should be replaced.

Storage

1. Remove battery and clean exterior.

2. Check fluid level and fill if low.

3. Cover terminals and bolts with light coat of grease.

4. Set battery on wood or in carton; store in cool, dry place.

5. Check every 20 days for fluid level and slow charge.

IMPORTANT: A discharged battery can be damaged by freezing.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-7

Testing

A strong battery must be maintained. If battery shows less than 9-1/2 volts when under start-

ing load, (at 80° F or 27° C) it should be recharged. Check with DC voltmeter.

74307

a-Voltmeter

b-Battery

Place battery under heavy load (as during engine cranking or with a variable resistor tester)

and test cell voltage while under load.

Certain conditions must be met before testing.

• Battery must be 60 to 100°F (16 to 38°C).

• Electrolyte level must be correct in all cells.

• Battery must be at least half charged.

• No obvious defects.

1. Check voltage per manufacturer’s specifications.

2. If readings are low, recharge and retest.

3. If readings remain low, battery should be replaced.

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-8 90-861329--1 MARCH 1999

Positive Current Flow

This is a general description of the positive current flow, from the battery and through the

system until the starter motor cranks.

• Battery to the solenoid switch (on starter) (RED battery cable).

• Solenoid switch to circuit breaker (RED).

• Circuit breaker to wire junction (RED-PUR).

• Wire junction to wiring harness plug (RED-PUR) terminal 6.

• Wiring harness plug to 20 amp fuse (RED-PUR).

• 20 amp fuse to ignition switch terminal I (RED-PUR). At this point ignition switch is turned

to START.

• Ignition switch terminal I to terminal C.

• Ignition switch terminal C to neutral start switch (YEL-RED). NEUTRAL START

SWITCH MUST BE AT NEUTRAL POSITION.

• Neutral start switch to wiring harness plug terminal 7 (YEL-RED).

• Wiring harness plug to starter solenoid (small terminal) (YEL-RED). Also ensure that

black (small terminal) wire is grounded.

• Starter solenoid is now “closed,” completing circuit between large terminal (RED-PUR)

and other large terminal (YEL-RED), causing starter motor to crank.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-9

Charging Guide

12 Volt Battery Recommended Rate* and Time for Fully Discharged Condition

Twenty Hour

Rating

Amperes

Ampere-Hours or

less

10 Hours 5 Hours

2-1/2

Hours

2 Hours

Above 50 to 75

Ampere-Hours

15 Hours

7-1/2

Hours

3-1/2

Hours

2-1/2

Hours

2 Hours

1-1/2

Hours

Above 75 to 100

Ampere-Hours

20 Hours 10 Hours 5 Hours 3 Hours

2-1/2

Hours

2 Hours

Above 100 to

150

Ampere-Hours

30 Hours 15 Hours

7-1/2

Hours

5 Hours

3-1/2

Hours

3 Hours

Above 150

Ampere-Hours

20 Hours 10 Hours

6-1/2

Hours

5 Hours 4 Hours

* Initial rate for constant voltage taper rate charger

To avoid damage, charging rate must be reduced or temporarily halted, if:

1. Electrolyte temperature exceeds 125° F (52° C).

2. Violent gassing or spewing of electrolyte occurs.

Battery is fully charged when, over a two hour period at a low charging rate in amperes, all

cells are gassing freely and no change in specific gravity occurs. For the most satisfactory

charging, the lower charging rates in amperes are recommended.

Full charge specific gravity is 1.260-1.280, corrected for temperature with electrolyte level

at split ring.

Battery Power as Affected by Temperature

74310

100%

83%

61%

45%

80°F

(27°C)

32°F (0°C)

0°F

(-18°C)

-20°F

(-29°C)

100%

165%

250%

350%

Power (Watts) Available Power (Watts) Required

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-10 90-861329--1 MARCH 1999

Slave Solenoid Identification

Types

There are two types of slave solenoids (“standard” or “switch”) used on MerCruiser engines.

These engines use a standard type solenoid; do not substitute a switch type solenoid.

The other engines use a slave solenoid to energize the starter motor solenoid. Some model

engines use the small terminal on the “switch type” solenoid for ignition by-pass during the

starting of the engine. Because of this, be sure to use correct type of slave solenoid for re-

placement.

Standard Type Slave Solenoid

74581

Starting Position Off Or Run Position

a-From Key Switch (12 Volts In Start Position)

b-To Ground

c-12 Volts From Battery

d-0 Volts From Starter

e-12 Volts To Starter

Switch Type Slave Solenoid

74582

Starting Position Off Or Run Position

a-From Key Switch (12 Volts in Start Position)

b-Mounting Bracket and Ground

c-12 Volts from Battery

d-0 Volts To Starter

e-0 Volts To Ignition Coil

f-12 Volts To Starter

g-12 Volts To Ignition Coil

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-11

Testing/Replacement

1. Using continuity meter, connect test leads as shown and connect 12-volt battery with

jumper leads as shown.

72630

2. If no meter movement is present, replace solenoid.

Solenoid Switch

The solenoid switch, along with plunger, return spring, and shift lever, are completely sealed

and permanently mount-ed in the drive housing. If solenoid is defective, entire drive housing

must be replaced.

Periodic Inspection

Cranking motor and solenoid are completely enclosed in the drive housing to prevent

entrance of moisture and dirt. However, periodic inspection is required as follows:

1. Inspect terminals for corrosion and loose connections.

2. Inspect wiring for frayed and worn insulation.

3. Check starter mounting bolts for tightness.

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-12 90-861329--1 MARCH 1999

PG260 Starter Motor

PG260 Specifications

Delco I.D. Number MerCruiser Part Number

9000820 50-806963

No Load Test

Brush Spring

Engine

Rotation

Volts

Min.

Amps

Max. Amp Min. rpm Max. rpm

Brush Spring

Tension Oz.

(Grams)

LH 10.6 60 95 2750 3250

83-104 oz. (2352-

2948)

Pinion Clearance .101-.160 (.025-4.06mm)

Bearing Depth (Gear) .011-.014 (0.28-.038mm) Maximum

Bearing Depth (Housing) .009-.017 (0.4mm) Maximum

Torque Specification

Fastener Location lb-ft Nm

Starter Mounting Bolts 30 41

Fastener Not Listed Tighten Securely

NOTE: The PG260 starter cannot be rebuilt. The only replacement components available

are the solenoid and drive housing.

Description

The Delco PG260 starter motor features small permanent magnets mounted inside the field

frame. These magnets take the place of current-carrying field coils mounted on iron pole

pieces. Internal gear reduction, approximately 4 to 1, through planetary gears results in

armature speeds in the 7000 rpm range. The armature and drive shaft are mounted on roller

or ball bearings in place of bushings. The solenoid switch, plunger, return spring, and shift

lever are permanently mounted in the drive housing.

CAUTION

The starter motor is designed to operate under great overload and produce a high

horsepower for its size. It can do this only for a short time, since considerable heat

accumulates and can cause serious damage. For this reason, the cranking motor

must never be used for more than 30 seconds at any one time. Cranking should not

be repeated without a pause of at least 2 minutes to permit the heat to escape.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-13

PG260 Exploded View

74270

1-Screw (2)

2-End Cap

3-Brush With Holder

4-Armature

5-Field Frame (With Permanent Magnets)

6-Washer

7-Shield

8-Planetary Gears

9-Shaft

10 - Gear

11 - Drive

12 - Collar

13 - Retaining Ring

14 - Trust Collar

15 - Drive Housing

16 - Nut

17 - Solenoid

18 - Solenoid Drive Arm

19 - Screw (3)

20 - Screw (2)

21 - Rubber Grommet

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-14 90-861329--1 MARCH 1999

Starter Motor Repair

Removal

WARNING

Disconnect battery cables at battery before removing starter.

1. Disconnect battery cables from battery.

2. Disconnect wires from solenoid terminals.

IMPORTANT: Some starter motors may use a special mounting shim for gaining fly-

wheel clearance. Do not lose this shim; it will be needed when remounting starter on

engine block.

3. Remove starter mounting bolts.

4. Pull starter assembly away from flywheel and remove from engine.

74523

a-Starter Bracket (If So Equipped)

Disassembly

1. Remove brush lead from solenoid and screws from end frame.

74041

a-Brush Lead

b-Screws

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-15

2. Remove through bolts and separate end frame from field frame and end cap.

74040

a-End Cap

b-Through Bolt

c-Drive Housing

3. Remove brush holder from end cap.

74037

a-Brush Holder

b-End Cap

c-Screws (2)

4. Remove armature and field frame from drive housing.

5. Pull armature out of field frame.

NOTE: Permanent magnets inside field frame will be holding armature in place.

74086

a-Armature

b-Field Frame

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-16 90-861329--1 MARCH 1999

6. Remove shield and washer.

74038

a-Shield

b-Washer

7. Remove the three screws retaining the solenoid. Remove solenoid from drive housing.

74036

a-Drive Housing

b-Solenoid

c-Screws (3)

8. Remove drive and associated parts from drive housing.

74035

a-Drive Housing

b-Drive

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-17

9. Remove solenoid arm and rubber grommet from the drive housing.

74018

74048

74105

a-Rubber Grommet

b-Solenoid

c-Drive Housing

10. Remove thrust collar, retaining ring and collar from planetary shaft.

74016

a-Thrust Collar

b-Retaining Ring

c-Collar

d-Drive

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-18 90-861329--1 MARCH 1999

11. Remove drive and gear from planetary shaft.

74087

a-Gear

b-Planetary Gear Shaft Assembly

c-Drive

Cleaning and Inspection

IMPORTANT: Do not use grease dissolving solvents to clean electrical components,

planetary gears, or drive. Solvent will damage insulation and wash the lubricant out

of the drive and gears. Use clean rags and compressed air to clean components.

1. Test over-running clutch action of drive. Pinion should turn freely in over-running direc-

tion and must not slip in cranking direction. Check pinion teeth. Check spring for tension

and drive collar for wear. Replace if necessary.

2. Check that brush holders are not damaged or bent and hold brushes against

commutator. Check brushes for wear; refer to “Brushes and Brush Holder.”

3. Inspect armature commutator. If badly grooved or out-of-round, turn down and undercut

commutator.

4. Inspect all roller bearing surfaces for wear. Check that bearings roll freely. If any

roughness is felt, replace bearings.

5. Inspect planetary gear assembly. Gears must mesh easily and roll freely with no binding.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-19

Armature Tests

TEST FOR SHORTS

Check armature for shorts by placing on growler and holding hack saw blade over armature

core while rotating armature. If saw blade vibrates, armature is shorted. After cleaning

between commutator bars, recheck. If saw blade still vibrates, replace armature.

01440

a-Hacksaw Blade

b-Armature Cover

c-Growler

TEST FOR GROUND

1. With continuity meter, place one lead on armature core or shaft and other lead on

commutator.

2. If meter hand moves, armature is grounded and must be replaced.

01441

a-Commutator

b-Armature Core

c-Shaft

d-Growler

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-20 90-861329--1 MARCH 1999

Armature Bearing (Commutator End)

REMOVAL

Use a universal puller plate, as shown, to remove bearing.

72068

a-Universal Puller Plate

b-Bearing

INSTALLATION

IMPORTANT: Brush holder must be installed on armature before installing armature

bearing.

Using the correct size driver, press on inner bearing race until it contacts shoulder of

armature shaft.

Gear Bearing

REMOVAL

Using the correct size driver, press bearing out of gear.

INSTALLATION

1. Using the correct size driver, press bearing into gear, from direction shown, to depth

specified.

72625

a-Depth - .011-.014 in. (0.28-0.38 mm)

b-Installation Direction

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-21

2. Lubricate bearing and gear teeth with a small amount of Quicksilver 2-4-C Marine

Lubricant with Teflon.

Shaft Assembly Bearing

IMPORTANT: Roller bearing is not replaceable. If bearing is defective, replace entire

shaft assembly. Apply Quicksilver 2-4-C Marine Lubricant with Teflon to bearing

before starter reassembly.

72070

a-Roller Bearing

Drive End Housing Bearing

REMOVAL

Using the correct size driver, press bearing out of housing.

72626

a-Drive End Housing

b-Bearing

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-22 90-861329--1 MARCH 1999

INSTALLATION

1. Using the correct size driver, press bearing into housing, from direction shown, to depth

specified.

72626

a-Depth - .009-.017 in. (0.25-0.45 mm)

b-Installation Direction

2. Lubricate bearing with a small amount of Quicksilver 2-4-C Marine Lubricant with Teflon.

Brushes and Brush Holder

INSPECTION

Replace brushes and holder when brush leads are touching guide.

Make sure brushes move freely in guides.

72069

a-Brush Leads

b-Guide

REMOVAL

1. Remove armature bearing as previously described.

2. Remove brush holder.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-23

INSTALLATION

1. Push each brush up into its guide to allow spring to hold it in place, as shown.

72072

a-Brush

b-Guide

c-Brush Spring

2. Place brush holder on armature and push brushes down against commutator, as shown.

72069

a-Brush Holder

b-Brush

c-Commutator

3. Install armature bearing as previously described.

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-24 90-861329--1 MARCH 1999

Reassembly

1. Install end frame on brush holder. Align holes of end frame with holes of brush holder.

Tighten screws securely.

76250

a-Screw (2)

b-End Cap

c-Brush Holder

d-Armature

2. Install gear and drive over planetary shaft.

74087

a-Planetary Shaft

b-Gear

c-Drive

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-25

3. Assemble drive on shaft assembly as follows:

a. Lubricate drive end of shaft assembly with SAE 10W oil.

b. Place gear over shaft.

c. Slide drive assembly onto shaft with pinion facing outward.

d. Slide retainer onto shaft with cupped surface facing end of shaft (away from pinion).

e. Position snap ring on upper end of shaft and hold in place with block of wood. Strike

wood block with hammer, thus forcing snap ring over end of shaft. Slide snap ring

down into groove.

72073

a-Snap Ring

b-Groove

c-Retainer

f. Assemble thrust collar on shaft with shoulder next to snap ring.

g. Position retainer and thrust collar next to snap ring. Then, using two pliers, grip

retainer and thrust collar and squeeze until snap ring is forced into retainer.

72074

a-Retainer

b-Thrust Collar

c-Snap Ring

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-26 90-861329--1 MARCH 1999

4. Install the planetary gears on planetary shaft.

5. Install solenoid arm and rubber grommet in the drive housing.

74018

74048

74105

a-Rubber Grommet

b-Solenoid

c-Drive Housing

6. Install drive and associated parts in drive housing.

74035

a-Drive Housing

b-Drive

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-27

7. Place solenoid in drive housing and tighten screws.

74036

a-Drive Housing

b-Solenoid

c-Screw (3)

8. Install shield and washer in drive housing.

74038

a-Shield

b-Washer

9. Install field frame over armature. Align slot in end cap and field frame for proper position-

ing of rubber grommet.

76251

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-28 90-861329--1 MARCH 1999

10. Install field frame and end cap in drive housing align slots in field frame with recess in

drive housing.

76252

a-Drive Housing

b-End Cap and Field Frame

11. Install through bolts and brush lead. Tighten fasteners securely.

Starter Solenoid

Testing/Replacement

1. Using continuity meter, connect test leads as shown, and connect 12 volt battery with

jumper leads as shown.

72630

a-Brush Lead

2. If no meter movement is present, replace solenoid.

3. Install through bolts and brush lead. Tighten fasteners securely.

4. Connect 12 volt battery positive (+) lead to solenoid switch terminal and negative (–)

lead to solenoid frame.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-29

5. Momentarily touch a jumper lead from solenoid motor to starter motor frame. This shifts

pinion into cranking position where it will remain until battery is disconnected.

72629

6. Push pinion back toward commutator end to eliminate slack.

7. Measure distance between pinion and pinion retainer.

8. If clearance is not within limits of .010-.160 in. (0.25-4.00 mm), it may indicate excessive

wear of solenoid linkage, shift lever yoke, or improper assembly of shift lever

mechanism. Replace worn or defective parts, since no provision is made for adjusting

pinion clearance.

72077

a-Pinion

b-Retainer

c-Feeler Gauge

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-30 90-861329--1 MARCH 1999

Installation

IMPORTANT: Install special mounting shim (if equipped) between starter motor and

engine block.

1. Place starter motor in position and install mounting bolts. Torque bolts to 30 lb-ft (41 Nm).

2. Connect YELLOW/RED wire to terminal S of solenoid. Connect ORANGE wire, RED

wire, and battery cable to large terminal of solenoid. Tighten fasteners securely. Coat

terminals with Quicksilver Liquid Neoprene. Install battery cable boot, if so equipped.

3. Connect battery cables to battery in the following order. Connect positive (+) cable to

positive (+) battery terminal and tighten cable clamp. Then connect negative (–) cable

to negative (–) terminal and tighten clamp.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-31

PG260F1 Starter Motor

PG260F1 Specifications

Delco I.D. Number MerCruiser Part Number

9000839 - 9000840 50-807904

No Load Test

Brush Spring

Engine

Rotation

Volts

Min.

Amps

Max. Amp Min. rpm Max. rpm

Brush Spring

Tension Oz.

(Grams)

LH 11.5 40 90 3200 4800

Brush Spring Length

Length New - 0.36 - 0.42 in. (9.2 - 10.7 mm)

Length Used - 0.18 - 0.23 in. (4.62 - 5.98 mm)

Pinion Clearance 0.009 - 0.160 in. (0.23-4.06 mm)

Bearing Depth (Gear) Flush - Inside

Bearing Depth (Housing) .009-.017 (0.4mm) Maximum

Torque Specifications

Fastener Location lb-ft Nm

Starter Mounting Bolts 30 41

All Other Fasteners Tighten Securely

Lubricants/Sealants

Description Part Number

Quicksilver Liquid Neoprene 92-25711--3

Quicksilver 2-4-C Marine Lubricant With Teflon 92-825407A3

Description

The Permanent Magnet Gear Reduction (PG200 and PG250) starter motors feature small

permanent magnets mounted inside the field frame (NOTE: The actual configuration of

these magnets differs between the PG200, PG250 and PG260; the field frames with

permanent magnets are not interchangeable. Otherwise, the units are similar.) These

magnets take the place of current-carrying field coils mounted on iron pole pieces. Internal

gear reduction, approximately 4 to 1, through planetary gears results in armature speeds

in the 7000 rpm range. The armature and drive shaft are mounted on roller or ball bearings

in place of bushings. The solenoid switch, plunger, return spring, and shift lever are

permanently mounted in the drive housing.

CAUTION

The starter motor is designed to operate under great overload and produce a high

horsepower for its size. It can do this only for a short time, since considerable heat

accumulates and can cause serious damage. For this reason, the cranking motor

must never be used for more than 30 seconds at any one time. Cranking should not

be repeated without a pause of at least 2 minutes to permit the heat to escape.

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-32 90-861329--1 MARCH 1999

Exploded View

74270

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-33

1-Screw (2)

2-End Frame and Bearing

3-Brush With Holder

4-Armature

5-Field Frame (With Permanent Magnets)

6-Washer

7-Shield

8-Planetary Gears

9-Shaft

10 - Gear

11 - Drive

12 - Collar

13 - Retaining Ring

14 - Trust Collar

15 - Drive Housing

16 - Nut

17 - Solenoid

18 - Solenoid Drive Arm

19 - Screw (3)

20 - Long Screw (2)

21 - Rubber Grommet

22 - Metal Disc

Starter Motor Repair

Removal

WARNING

Disconnect battery cables at battery before removing starter.

1. Disconnect battery cables from battery.

2. Disconnect wires from solenoid terminals.

IMPORTANT: Some starter motors may use a special mounting shim for gaining fly-

wheel clearance. Do not lose this shim; it will be needed when remounting starter on

engine block.

3. Remove starter mounting bolts.

4. Pull starter assembly away from flywheel and remove from engine.

Disassembly

1. Remove brush lead from solenoid and long screws from end frame.

75820

a-Brush Lead

b-Screws

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-34 90-861329--1 MARCH 1999

2. Separate end frame from field frame.

3. Remove brush holder from end frame.

4. Remove armature and field frame from drive housing.

5. Pull armature out of field frame.

NOTE: Permanent magnets inside field frame will be holding armature in place.

74270

a-End Frame and Bearing

b-Screws (2)

c-Brush Holder

d-Armature

e-Field Frame

6. Remove shield and washer from drive housing.

74038

a-Shield

b-Washer

c-Drive Housing

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-35

7. Remove the three screws retaining the solenoid. Remove solenoid from drive housing.

74036

a-Drive Housing

b-Solenoid

c-Screws (3)

8. Remove drive and associated parts from drive housing.

74035

75821

a-Drive Housing

b-Drive

9. Remove solenoid arm, metal disc and rubber grommet from the drive housing.

75821

a-Rubber Grommet

b-Metal Disc

c-Solenoid Arm

d-Drive Housing

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-36 90-861329--1 MARCH 1999

10. Remove thrust collar, retaining ring and collar from planetary shaft with drive.

75821

a-Thrust Collar

b-Retaining Ring (Inside Collar)

c-Collar

d-Planetary Shaft and Drive

11. Remove drive and gear from planetary shaft.

74087

Typical

a-Gear

b-Planetary Gear Shaft Assembly

c-Drive

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-37

Cleaning and Inspection

IMPORTANT: Do not use grease dissolving solvents to clean electrical components,

planetary gears, or drive. Solvent will damage insulation and wash the lubricant out

of the drive and gears. Use clean rags and compressed air to clean components.

1. Test over-running clutch action of drive. Pinion should turn freely in over-running direc-

tion and must not slip in cranking direction. Check pinion teeth. Check spring for tension

and drive collar for wear. Replace if necessary.

2. Check that brush holders are not damaged or bent and hold brushes against commuta-

tor. Check brushes for wear.

3. Inspect armature commutator. If badly grooved or out-of-round, turn down and undercut

commutator.

4. Inspect all roller bearing surfaces for wear. Check that bearings roll freely. If any rough-

ness is felt, replace bearing.

5. Inspect planetary gear assembly. Gears must mesh easily and roll freely with no binding.

Armature Tests

TEST FOR SHORTS

Check armature for shorts by placing on growler and holding hack saw blade over armature

core while rotating armature. If saw blade vibrates, armature is shorted. After cleaning

between commutator bars, recheck. If saw blade still vibrates, replace armature.

01440

a-Hacksaw Blade

b-Armature Core

c-Growler

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-38 90-861329--1 MARCH 1999

TEST FOR GROUND

1. With continuity meter, place one lead on armature core or shaft and other lead on com-

mutator.

2. If meter hand moves, armature is grounded and must be replaced.

01441

a-Commutator

b-Armature Core

c-Shaft

d-Growler

Reassembly

1. Install brush holder and bearing on armature.

2. Align brush lead grommet with field frame cut-out. Align holes of end frame with holes

of brush holder and drive housing. Install end frame on brush holder. Tighten screws

securely.

75821

a-Screw (2)

b-End Frame

c-Brush Holder

d-Armature

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-39

3. Install gear and drive over planetary shaft.

74087

Typical

a-Planetary Gear Shaft Assembly

b-Gear

c-Drive

4. Assemble drive on shaft assembly as follows:

a. Lubricate drive end of shaft assembly with SAE 10W oil.

b. Place gear over shaft.

c. Slide drive assembly onto shaft with pinion facing outward.

d. Slide retainer onto shaft with cupped surface facing end of shaft (away from pinion).

e. Position snap ring on upper end of shaft and hold in place with block of wood. Strike

wood block with hammer, thus forcing snap ring over end of shaft. Slide snap ring

down into groove.

72073

a-Snap Ring

b-Groove

c-Retainer

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-40 90-861329--1 MARCH 1999

f. Assemble thrust collar on shaft with shoulder next to snap ring.

g. Position retainer and thrust collar next to snap ring. Then, using two pliers, grip

retainer and thrust collar and squeeze until snap ring is forced into retainer.

72074

a-Retainer

b-Thrust Collar

c-Snap Ring

5. Install the planetary gears on planetary shaft.

6. Install solenoid arm, metal disc and rubber grommet in the drive housing.

NOTE: Solenoid arm is designed to fit only one way. Do not use force.

75821

a-Rubber Grommet

b-Metal Disc

c-Solenoid Arm

d-Drive Housing

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-41

7. Install drive and associated parts in drive housing.

74035

75821

a-Drive Housing

b-Drive

8. Attach solenoid arm to solenoid. Place solenoid in drive housing and tighten screws.

74036

a-Drive Housing

b-Solenoid

c-Screw (3)

9. Install washer and shield in drive housing.

74038

75821

a-Washer

b-Shield

c-Drive Housing

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-42 90-861329--1 MARCH 1999

10. Install field frame over armature. Align slot in field frame with rubber grommet.

75821

a-Armature

b-Field Frame Slot

c-Rubber Grommet

11. Install field frame and end frame in drive housing.

12. Install long screws and brush lead. Tighten fasteners securely.

75821

a-End Frame

b-Field Frame

c-Drive Housing

d-Long Screws

e-Brush Lead

Starter Solenoid

TESTING / REPLACEMENT

Pinion clearance must be checked after reassembly of starter motor.

1. Disconnect brush lead from solenoid motor and insulate it carefully.

74041

a-Brush Lead

2. Connect 12 volt battery positive (+) lead to battery terminal and negative (–) lead to

frame.

INDEX

STARTING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4A-43

3. Momentarily touch a jumper lead from battery terminal to switch terminal. This shifts pin-

ion into cranking position where it will remain until battery is disconnected.

72629

4. Push pinion back toward commutator end to eliminate slack.

5. Measure distance between pinion and pinion retainer.

6. If clearance is not within limits of .010-.160 in. (0.25-4.00 mm), it may indicate excessive

wear of solenoid linkage, shift lever yoke, or improper assembly of shift lever mecha-

nism. Replace worn or defective parts, since no provision is made for adjusting pinion

clearance.

72077

a-Pinion

b-Retainer

c-Feeler Gauge

INDEX

STARTING SYSTEM SERVICE MANUAL NUMBER 26

Page 4A-44 90-861329--1 MARCH 1999

Installation

IMPORTANT: Install special mounting shim (if equipped) between starter motor and

engine block.

1. Place starter motor in position and install mounting bolts. Torque bolts to 30 lb-ft (41 Nm).

2. Connect YELLOW/RED wire to terminal S of solenoid. Connect ORANGE wire, RED

wire, and battery cable to large terminal of solenoid. Tighten fasteners securely. Coat

terminals with Quicksilver Liquid Neoprene. Install battery cable boot, if so equipped.

3. Connect battery cables to battery in the following order. Connect positive (+) cable to

positive (+) battery terminal and tighten cable clamp. Then connect negative (–) cable

to negative (–) terminal and tighten clamp.

INDEX

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-1

ELECTRICAL SYSTEM

Section 4B - Ignition System

Table of Contents

Identification 4B-2. . . . . . . . . . . . . . . . . . . . . . . . . .

Replacement Parts Warning 4B-2. . . . . . . . . . . .

Torque Specifications 4B-2. . . . . . . . . . . . . . . . . .

Tools 4B-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Special Tools 4B-3. . . . . . . . . . . . . . . . . . . . . . .

Lubricants/Sealants/Adhesives 4B-3. . . . . . . . . .

Specifications 4B-4. . . . . . . . . . . . . . . . . . . . . . . . .

Timing 4B-4. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Spark Plugs 4B-4. . . . . . . . . . . . . . . . . . . . . . . .

GM 4-Cylinder In-line Firing 4B-4. . . . . . . . . .

Description 4B-5. . . . . . . . . . . . . . . . . . . . . . . . . . .

Precautions 4B-6. . . . . . . . . . . . . . . . . . . . . . . . . .

Cleaning And Inspection 4B-7. . . . . . . . . . . . . . .

Spark Plugs 4B-7. . . . . . . . . . . . . . . . . . . . . . . .

Spark Plug Wires 4B-7. . . . . . . . . . . . . . . . . . .

Distributor Cap and Rotor 4B-8. . . . . . . . . . . .

Distributor Installation 4B-8. . . . . . . . . . . . . . . . . .

Engine Not Disturbed 4B-8. . . . . . . . . . . . . . .

Engine Disturbed 4B-9. . . . . . . . . . . . . . . . . . .

Ignition Timing 4B-9. . . . . . . . . . . . . . . . . . . . . . . .

Component Tests 4B-12. . . . . . . . . . . . . . . . . . . .

Testing Ignition Module 4B-12. . . . . . . . . . . . .

Testing Ignition Coil 4B-13. . . . . . . . . . . . . . . .

Testing Pickup Coil 4B-13. . . . . . . . . . . . . . . .

Advance Curve 4B-15. . . . . . . . . . . . . . . . . . . . . .

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-2 90-861329--1 MARCH 1999

Identification

70103

DELCO EST (Electric Spark Timing)

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to mini-

mize risks of fire and explosion.

Use of replacement electrical, ignition or fuel system components, which do not

comply with these rules and regulations, could result in a fire or explosion hazard

and should be avoided.

Torque Specifications

Fastener Location lb-ft Nm

Distributor Clamp 3/8-16 20 27

Spark Plugs (14 mm) 22 30

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-3

Tools

Description Part Number

Dwell Meter 91-59339

Magneto Analyzer 91-76032

Remote Starter Switch 91-52024A1

Timing Light 91-99379

Volt / Ohm Meter 91-99750A1

Timing Jumper 91-818812A1

Point Spring Tension Gauge Obtain Locally

Special Tools

Kent-Moore Special Tools

29784 Little Mack

Roseville, MI 48066

Phone: (313) 574-2332

Module Tester J24642

Lubricants/Sealants/Adhesives

Description Part Number

Distributor Cam Lubricant Obtain Locally

Liquid Neoprene 92-25711--3

Silicone Dielectric Compound 92-802882A1

Heat Transfer Compound 92-805701, 92-805701--1

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-4 90-861329--1 MARCH 1999

Specifications

Timing

Timing (At Idle rpm)

1° BTDC

/ 1° ATDC

/ 2° ATDC

Timing must be set using a special procedure as outlined in this section. Timing cannot be properly set using

the conventional method.

Serial number break: 0L096999 and below

Serial number break: 0L097000 - 0L0340999

Serial number break: 0L341000 and above.

Spark Plugs

Spark Plug Gap .035 In. (0.9 mm)

3.0L

AC-MR43LTS

NGK-BPR6EFS

Champion RS12YC

GM 4-Cylinder In-line Firing

50683

Firing Order 1-3-4-2

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-5

Description

EST or Electronic Spark Timing is a High Energy Ignition System (HEI). The distributor itself

has no centrifugal advance mechanism or devices.

The spark plug wires are a carbon-impregnated cord conductor with a silicone rubber jacket.

It is important they be handled with care, and routed so as not to cross each other or to be

in contact with other parts of the engine to prevent rubbing.

The EST System uses a square coil with epoxy covered windings to protect against mois-

ture and arc-over.

The timing cannot be set the same way that other ignition systems were.

70106

a-Distributor with Spark Plug Wires

b-Wires (WHITE) Used in Timing Procedure

c-Wire from Shift Interrupt Switch

d-Distributor Harness

e-Engine Harness Wire (PURPLE AND GRAY)

f-Coil

EST uses a magnetic pulse generator and an electronic module to primary circuit current.

Internally the Pulse Generator, or magnetic pick-up assembly, takes the place of conven-

tional points. A timer core on the main shaft of the distributor has external teeth which align

with an equal number of pole piece teeth (four for a four cylinder engine). The electronic

module is small enough to allow it to be mounted inside the distributor, and contains the cir-

cuits necessary for dwell control and advance of the timing.

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-6 90-861329--1 MARCH 1999

Molded into the module is a two-prong connector for the coil terminals and four prong con-

nector. Only three of the four terminals of the second connector are used by MerCruiser (one

for the shift interrupt and two white leads are used to “freeze” advance for properly setting

initial timing). Inside the distributor, the pick-up coil attaches to the module at a molded prong

connector.

70107

a-Magnetic Pulse Generator

b-Electronic Module

c-Two Prong Connector

d-Four Prong Connector

e-Pick-up Coil Connector

f-Timer Core

g-Pole Piece Teeth

h-External Teeth

Precautions

WARNING

When performing the following procedure, be sure to observe the following:

• Be sure that engine compartment is well ventilated and that no gasoline vapors

are present, to avoid the possibility of fire.

• Be sure to keep hands, feet and clothing clear of moving parts.

• Do not touch or disconnect any ignition system parts while engine is running.

• Do not reverse battery cable connections. System is negative (–) ground.

• Do not disconnect battery cables while engine is running.

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-7

Cleaning And Inspection

Spark Plugs

1. Inspect each plug individually for badly worn electrodes, glazed, broken or blistered

porcelain and replace plug where necessary.

2. Inspect each spark plug for manufacturer and heat range. All plugs must be the same

manufacturer and number or heat range. Refer to “Specifications” for spark plug num-

bers.

3. Check spark plug gaps with a round feeler gauge. Adjust if necessary.

50674

Spark Plug Detail

a-Porcelain Insulator

b-Check For Cracks In This Area of Porcelain

c-Shell

d-Proper Gap

e-Side Electrode (Gap Adjustment)

f-Center Electrode (File Flat When Adjusting Gap)

IMPORTANT: Tapered seat spark plugs are not interchangeable with non-tapered

(with gasket) spark plugs.

4. Clean spark plug seating area. DO NOT use gaskets on taper seat plugs. Install spark

plugs and torque to 22 lb-ft (30 Nm). Heat transfer and a gas-tight seal must be achieved.

Spark Plug Wires

1. Inspect spark plug wires for damage.

2. Check spark plug wires for continuity.

3. Replace any wires that are cracked, cut or have damaged spark plug boots.

4. Replace any wires that do not show continuity from end to end.

5. Reinstall spark plug wires in proper order.

IMPORTANT: Proper positioning in spark plug wires is important to prevent cross

firing.

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-8 90-861329--1 MARCH 1999

Distributor Cap and Rotor

1. Loosen distributor cap retaining screws.

2. Remove distributor cap.

3. Clean cap with warm soap and water and blow off with compressed air.

4. Check cap contact for excessive burning or corrosion. Check center contact for

deterioration.

IMPORTANT: Distributor caps (for marine use) should have brass contacts, alumi-

num contacts should not be used.

5. Check cap for cracks or carbon tracks using magneto analyzer.

6. Remove rotor.

7. Check for burned or corroded center contact.

8. Check rotor for cracks and carbon tracks using magneto analyzer.

9. Install rotor on shaft. Be sure rotor is completely seated on shaft.

10. Place cap on distributor.

11. Tighten retaining screws securely.

Distributor Installation

Engine Not Disturbed

1. Install new gasket on distributor housing.

2. Turn rotor approximately 1/8 turn in a counter-clockwise direction past mark previously

scratched on distributor housing.

3. Work distributor down into position in engine block with distributor positioned as noted

during removal.

IMPORTANT: It may be necessary to move rotor slightly to start gear into mesh

camshaft gear, but rotor should line up with mark when distributor is down in place.

Distributor shaft must enter oil pump shaft for complete installation.

4. Replace and tighten distributor hold-down bolt and clamp. Connect primary lead to coil.

Also install spark plug and coil secondary wires, if removed.

IMPORTANT: Wires must be installed in supports, to prevent cross-firing. Firing

order is 1-3-4-2.

5. Install rotor.

6. Time ignition as outlined under “Ignition Timing,” in this section.

7. Replace distributor cap.

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-9

Engine Disturbed

1. Locate No. 1 piston in firing position by either of two methods described below.

a. Remove No. 1 spark plug and, with finger on plug hole, crank engine until compres-

sion is felt in No. 1 cylinder. Continue cranking until pointer lines up with timing mark

on crankshaft pulley, or

b. Remove rocker cover and crank engine until No. 1 intake valve closes, continuing

to crank slowly until pointer lines up with timing mark on crankshaft pulley.

2. Position distributor to opening in block in normal installed attitude.

3. Position rotor to point toward front of engine (with distributor housing held in installed

attitude), then turn rotor counterclockwise approximately 1/8-turn more to the left and

push distributor down to engage camshaft. It may be necessary to rotate rotor slightly

until camshaft engagement is felt.

4. While pressing down firmly on distributor housing, engage starter a few times to make

sure oil pump shaft is engaged. Install hold-down clamp and bolt and snug up bolt.

5. Turn distributor body slightly until points just open and tighten distributor clamp bolt.

6. Place distributor cap in position and check that rotor lines up with terminal for No. 1 spark

plug. Install cap.

7. Install cap, distributor primary lead to coil. Check and connect spark plug wires, if they

have been removed. Wires must be installed in their proper location in supports to

prevent cross-firing. Firing order is 1-3-4-2.

8. Install rotor.

9. Replace distributor cap.

10. Time ignition as outlined under “Ignition Timing,” in this section.

Ignition Timing

IMPORTANT: Failure to follow the timing procedure instructions will result in

improper timing causing performance problems and possible severe engine

damage.

1. Connect timing light (91-99379 or similar) to No. 1 spark plug wire. Connect power sup-

ply leads on light to 12 volt battery. Refer to Specifications - “Engine Rotation and Firing

Order,” for cylinder numbering and location.

2. Connect a shop tachometer to engine.

NOTE: Before starting engine make sure the timing tab and mark on damper are clean.

Chalk or white paint on timing mark on damper may help visibility.

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-10 90-861329--1 MARCH 1999

3. Start engine and run at idle speed until it reaches normal operating temperature.

70103

a-WHITE Leads

b-Jumper Lead

4. Install a jumper wire between the two WHITE leads on the distributor. Use Quicksilver

91-818812A1, or fabricate a jumper wire using a 6 in. (150 mm) section of 16 gauge wire

with two male bullet terminal ends connected.

5. Bypass the shift interrupt switch, as follows:

a. Disconnect wires at shift interrupt switch.

b. Temporarily join the engine harness wires

together.

75499

75552

IMPORTANT: Do not fail to reconnect these two wires to the shift interrupt switch

when timing procedures are complete.

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-11

6. Aim timing light at timing tab, located on the timing gear cover and crankshaft torsional

damper. Check the timing. Refer to “Specifications.”

72328

73664

Typical

7. Adjust timing by loosening distributor clamp and rotating distributor body as required

until timing mark on damper or pulley lines up with the mark on tab specified in

“Specifications.” Tighten clamp and recheck location of timing mark.

8. Aim timing light at timing tab and recheck location of timing mark. Repeat Step 7 until

timing is correct.

9. Stop the engine. Torque distributor hold down bolt to 20 lb-ft (27 Nm).

10. Reconnect the two wires to the shift interrupt switch.

75499

75552

75553

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-12 90-861329--1 MARCH 1999

IMPORTANT: Be sure to remove jumper wire before returning engine to service,

otherwise timing will not advance.

11. Remove jumper wire at distributor white leads.

70103

a-WHITE Leads

b-Jumper Lead

12. With timing light still connected, start the engine and run at IDLE. Verify that timing did

advance to :

• If initial timing is 1° BTDC: 12° BTDC, plus or minus 2°. At 2400-2800 rpm maximum

(total) advance is obtained and should be 23° BTDC (plus or minus 2°).

• If initial timing is 1° ATDC: 14° BTDC, plus or minus 2°. At 2400-2800 rpm maximum

(total) advance is obtained and should be 25° BTDC (plus or minus 2°).

• If initial timing is 2° ATDC: 15° BTDC, plus or minus 2°. At 2400-2800 rpm maximum

(total) advance is obtained and should be 26° BTDC (plus or minus 2°).

13. Stop the engine and remove the timing light.

Component Tests

The following tests can be made with the distributor and coil mounted on or off the engine.

The test procedures will check each component of the distributor and ignition coil. Distribu-

tor cap and rotor should be checked for corrosion, cracks, carbon tracks or wear. Replace

if needed.

Testing Ignition Module

In order to test the module, an approved module tester, such as Kent-Moore Tester (J24642

or equivalent), must be used. Be certain to follow the manufacturer’s directions precisely

for proper results. However, do not overlook that corrosion on the terminals of the module

could cause improper ignition action and should therefor be inspected and cleaned if

needed.

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-13

Testing Ignition Coil

1. If not already done, disconnect wiring from ignition coil. Connectors are molded and

keyed to assure proper positioning. The terminal (e) feeds 12 volts to the distributor.

NOTE: Upon reinstallation, first install black connector (distributor harness) to coil. Then

install gray connector (engine harness).

2. Set ohmmeter to “Rx100” scale and connect one lead to 12 volt terminal (b) of coil and

the other lead to “ground” (d), any clean metal on the coil frame. Reading should be infi-

nite. If not, replace coil.

3. Set ohmmeter to “Rx100” scale and connect to 12 volt terminal (b) and terminal (c).

Reading should be approximately .4 ohms. If not, replace coil.

4. Set ohmmeter to “Rx1” scale and connect to 12 volt terminal (b) and tachometer terminal

(f). Reading should be approximately .4 ohms. If not, replace coil.

5. Set ohmmeter to “Rx100” high scale. Connect ohmmeter to 12 volt terminal (b) and to

coil high tension post (a). Reading should be between 7800 and 8800 ohms. If it reads

outside of this range, replace coil.

Testing Pickup Coil

70105

a-Connector

b-GREEN Lead

c-WHITE Lead

d-Distributor Housing

1. Remove distributor cap.

2. Identify the two pickup coil leads. On almost all applications these two leads are one

WHITE and one GREEN. Remove the connector that houses these two leads from the

module.

3. Set ohmmeter to “Rx1” scale. Connect one lead of ohmmeter to WHITE lead and the

other to distributor housing. Reading should be infinite. If not, replace pickup coil.

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-14 90-861329--1 MARCH 1999

4. Repeat Step 3 with ohmmeter connected to GREEN lead. Reading should be infinite.

If not, replace pickup coil.

5. Set ohmmeter to “Rx100” scale. Connect ohmmeter to GREEN and WHITE pickup coil

leads. Reading should be constant, unchanging value in the range of 500-1500 ohms.

If not, replace pickup coil. Be certain to flex leads by hand during this test to locate pos-

sible intermittent “open” circuits (loss of continuity). If any exist, replace pickup coil.

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-15

Advance Curve

Module Part Number: 811637

Module Advance: See Notice

Initial Timing: 1° BTDC

/ 1° ATDC

/ 2° ATDC

Total Advance: 23°

Serial number break: 0L340999 and below unless specified differently below

Serial number break: 0K001529 - 0L097000 Timing changes to 1° ATDC only if engine experiences a cylinder

head gasket failure that has blown out toward the intake exhaust manifold on the port side of the engine.

Serial number break: 0L341000 and above.

NOTICE

Advance curve includes initial timing. DO NOT add initial timing degrees to total

advance degrees.

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

10°

15°

20°

25°

30°

35°

ENGINE R.P.M.

TOTAL SPARK ADVANCE

70808-15

MAX.

MIN.

Initial Timing 1° BTDC

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-16 90-861329--1 MARCH 1999

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

10°

15°

20°

25°

30°

35°

ENGINE R.P.M.

TOTAL SPARK ADVANCE

70808-15

MAX.

MIN.

Initial Timing 1° ATDC

Index

IGNITION SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4B-17

500 1000 1500 2000 2500 3000 3500 4000 4500 5000

10°

15°

20°

25°

30°

35°

ENGINE R.P.M.

TOTAL SPARK ADVANCE

70808-15

MAX.

MIN.

Initial Timing 2° ATDC

Index

IGNITION SYSTEM SERVICE MANUAL NUMBER 26

Page 4B-18 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

Index

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-1

ELECTRICAL SYSTEM

Section 4C - Charging System

Table of Contents

Identification 4C-2. . . . . . . . . . . . . . . . . . . . . . . . . .

Replacement Parts Warning 4C-3. . . . . . . . . . . .

Description 4C-3. . . . . . . . . . . . . . . . . . . . . . . . . . .

Precautions 4C-4. . . . . . . . . . . . . . . . . . . . . . . . . .

System Components 4C-5. . . . . . . . . . . . . . . . . .

Periodic Maintenance 4C-6. . . . . . . . . . . . . . . . . .

Drive Belt Tension Adjustment 4C-7. . . . . . . . . .

Alternator 4C-7. . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Tests (Alternator on

Engine) 4C-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Circuitry Test 4C-8. . . . . . . . . . . . . . . . . . . . . . .

Current Output Test 4C-10. . . . . . . . . . . . . . . .

Voltage Output Test 4C-11. . . . . . . . . . . . . . . .

Alternator Repair 4C-12. . . . . . . . . . . . . . . . . . . . .

Removal 4C-12. . . . . . . . . . . . . . . . . . . . . . . . .

Exploded View 4C-13. . . . . . . . . . . . . . . . . . . .

Disassembly 4C-14. . . . . . . . . . . . . . . . . . . . . .

Cleaning and Inspection 4C-18. . . . . . . . . . . .

Component Testing 4C-19. . . . . . . . . . . . . . . .

Reassembly 4C-23. . . . . . . . . . . . . . . . . . . . . .

Installation 4C-28. . . . . . . . . . . . . . . . . . . . . . . . . .

Batteries 4C-29. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Battery Cables 4C-29. . . . . . . . . . . . . . . . . . . .

Mando 55 Amp Alternator 4C-30. . . . . . . . . . . . .

Identification 4C-30. . . . . . . . . . . . . . . . . . . . . .

Replacement Parts Warning 4C-30. . . . . . . .

Specifications 4C-30. . . . . . . . . . . . . . . . . . . . .

Tools 4C-31. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lubricants/Sealants/Adhesives 4C-31. . . . . .

Torque Specifications 4C-31. . . . . . . . . . . . . .

Battery Isolator Diagram 4C-32. . . . . . . . . . . .

Mando 65 Amp Alternator 4C-33. . . . . . . . . . . . .

Identification 4C-33. . . . . . . . . . . . . . . . . . . . . .

Replacement Parts Warning 4C-33. . . . . . . .

Specifications 4C-33. . . . . . . . . . . . . . . . . . . . .

Tools 4C-34. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lubricants/Sealants/Adhesives 4C-34. . . . . .

Torque Specifications 4C-34. . . . . . . . . . . . . .

Exploded View 4C-35. . . . . . . . . . . . . . . . . . . . . . .

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-2 90-861329--1 MARCH 1999

Identification

72078

Mando 55 Amp Alternator

a-Excitation Wire - PURPLE

b-Sensing Wire - RED/PURPLE

c-Mando Part Number (Hidden In This View)

76093

Mando 65 Amp Alternator

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-3

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to mini-

mize risks of fire and explosion.

Use of replacement electrical, ignition or fuel system components, which do not

comply with these rules and regulations, could result in a fire or explosion hazard

and should be avoided.

Description

The alternator has a rotor, which is supported in two end frames by ball bearings, and is

driven by a pulley at approximately twice engine speed. The rotor contains a field winding

that is enclosed between two multiple-finger pole pieces. The ends of the field winding are

connected to two brushes (mounted in the rear end frame) which make continuous sliding

(or slipping) contact with the slip rings. The current (flowing through the field winding)

creates a magnetic field that causes the adjacent fingers of the pole pieces to become

alternate north and south magnetic poles.

A 3-phase stator is mounted directly over the rotor pole pieces and between two end frames.

It consists of three windings wound 120 degrees electrically out-of-phase on the inside of

a laminated core. The windings are all connected together on one end, while the other ends

are connected to a full-wave rectifier bridge.

The rectifier bridge contains six diodes which are arranged so that current flows from

ground, through the stator and to the output terminal, but not in the opposite direction.

When current is supplied to the rotor field winding, and the rotor is turned, the movement

of the magnetic fields created induces an alternating current into the stator windings. The

rectifier bridge then changes this alternating current to direct current which appears at the

output terminal. A diode trio also is connected to the stator windings to supply current to the

regulator and the rotor field during operation.

Voltage output of the alternator is controlled by regulating the current supplied to the rotor

field. This is accomplished by a transistorized voltage regulator that senses the voltage at

the battery and regulates the field current to maintain alternator voltage within prescribed

limits for properly charging the battery. Current output of the alternator does not require reg-

ulation, as maximum current output is self-limited by the design of the alternator. As long

as the voltage is regulated within the prescribed limits, the alternator cannot produce exces-

sive current. A cut-out relay in the voltage regulator also is not required, as the rectifier

diodes (which allow current to flow in one direction only) prevent the battery from discharg-

ing back through the stator.

Due to the lack of residual magnetism in the rotor pole pieces, a small amount of current

must be supplied to the rotor field to initially start the alternator charging. This is accom-

plished by means of an excitation circuit in the regulator which is connected to the ignition

switch. Once the alternator begins to produce output, field current is supplied solely by the

diode trio, as explained, preceding.

The alternator also is equipped with a fan (mounted on the rotor shaft) which induces air flow

through the alternator to remove the heat created by the rectifiers and stator. A capacitor

protects the rectifier system from high voltages and suppresses radio noise.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-4 90-861329--1 MARCH 1999

Precautions

CAUTION

The following precautions MUST BE observed when working on the alternator system.

Failure to observe these precautions may result in serious damage to the alternator or

alternator system.

• DO NOT attempt to polarize the alternator.

• DO NOT short across or ground any of the terminals on the alternator, except as spe-

cifically instructed in the “Troubleshooting Tests.”

• NEVER disconnect the alternator output lead or battery cables when the alternator is

being driven by the engine.

• NEVER disconnect regulator lead from alternator regulator terminal when the alterna-

tor is being driven by the engine.

• ALWAYS remove negative (–) battery cable from battery before working on alternator

system.

• When installing battery, BE SURE to connect the positive (+) battery cable to the posi-

tive (+) battery terminal and the negative (–) (grounded) battery cable to negative (–)

battery terminal.

• If a charger or booster battery is to be used, BE SURE to connect it in parallel with exist-

ing battery (positive to positive; negative to negative).

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-5

System Components

The alternator system consists of the alternator, battery, the ignition switch and the wiring

which connects these components.

72933

a-Battery

b-Ground Stud

c-Starter Motor

d-Circuit Breaker (not on all models)

e-Alternator

f-Harness Plug

g-Battery Meter

h-Ignition Switch

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-6 90-861329--1 MARCH 1999

Periodic Maintenance

The following maintenance check should be performed every 50 hours or 60 days

(whichever comes first) in fresh water areas or every 25 hours or 30 days in salt water areas.

CAUTION

Remove all battery cables from battery (before conducting the following check) to

prevent accidentally shorting out electrical system.

1. Inspect entire alternator system for corroded or loose connectors.

2. Check wiring for frayed or worn insulation.

3. Check alternator drive belt for excessive wear, cracks, fraying and glazed surfaces.

Also, check drive belt tension and adjust, if necessary, as explained under “Drive Belt

Tension Adjustment.”

4. Check alternator mounting bolts for adequate tightness.

5. Inspect slip ring end frame flame arrestor screen for debris and clean, if necessary, using

compressed air or a cloth. Screen MUST BE clean, or alternator may overheat.

72078

a-Inspect This Area

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-7

Drive Belt Tension Adjustment

Alternator

1. Install drive belt on pulleys and adjust tension as follows:

a. Pivot alternator away from engine, as required, until correct tension is obtained as

shown. Belt should depress 1/4in. (6 mm).

76094

a-Check Point

b-Alternator Pivot Bolt

b. After obtaining correct tension, securely retighten alternator brace attaching bolts

and alternator mounting bolts.

2. If a new drive belt has been installed, recheck belt tension after running for five minutes.

Troubleshooting Tests (Alternator on Engine)

Use the following tests in conjunction with the “Troubleshooting” in Section 1C. Before pro-

ceeding with the tests, however, perform the following checks to eliminate possible problem

areas. Also observe “Precautions,” earlier in this section, to prevent damage to alternator

system.

1. If problem is an undercharged battery, check to ensure that undercharged condition has

not been caused by excessive accessory current draw or by accessories which have

accidentally been left on. Also, check that undercharged condition has not been caused

by running engine at too low a speed for extended periods of time.

2. Check physical condition and state of charge of battery, as outlined in “Battery - Storage”

in Section 4A. Battery MUST BE at least 75% (1.230 specific gravity) of fully charged

to obtain valid results in the following tests. If not, charge battery before testing system.

3. Inspect entire alternator system wiring for defects. Check all connections for tightness

and cleanliness, particularly battery cable clamps and battery terminals.

4. Check alternator drive belt for excessive wear, cracks, fraying and glazed surfaces and

replace if necessary. Also, check drive belt tension and adjust if necessary, as outlined

under “Drive Belt Tension Adjustment.”

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-8 90-861329--1 MARCH 1999

Circuitry Test

Perform the following tests, using a 0-20 volt DC voltmeter, to check that all of the circuits

between the alternator and the other components within the alternator system are in good

condition.

OUTPUT CIRCUIT

1. Connect positive (+) voltmeter lead to alternator output terminal and negative (–) lead

to a ground terminal on alternator.

2. Wiggle engine wiring harness while observing voltmeter. Meter should indicate approxi-

mate battery voltage and should not vary. If no reading is obtained, or if reading varies,

check alternator output circuit for loose or dirty connections or damaged wiring.

72784

a-Output Wire - ORANGE

b-Excitation Wire - PURPLE

c-Sensing Wire - RED/PURPLE

d-Voltmeter (0-20 Volts)

e-Ground

EXCITATION CIRCUIT

1. Connect positive (+) voltmeter lead to tie strap terminal on alternator and negative (–)

lead to a ground terminal on alternator (Test 1).

2. Turn ignition switch to ON position and note voltmeter reading. Reading should be 1.3

to 2.5 volts.

3. If no reading is obtained, an opening exists in alternator excitation lead or in excitation

circuit of regulator. Unplug PURPLE lead from regulator. Connect positive voltmeter

lead to PURPLE lead and negative voltmeter leads to ground (Test 2). If voltmeter now

indicates approximate battery voltage, voltage regulator is defective and must be re-

placed. If no voltage is indicated, check excitation circuit for loose or dirty connections

or damaged wiring.

4. If reading is between .75 and 1.1 volts, rotor field circuit probably is shorted or grounded.

Disassemble alternator and test rotor as outlined under “Alternator Repair,” following.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-9

5. If reading is between 6.0 and 7.0 volts, rotor field circuit probably is open. Remove

regulator and inspect for worn brushes or dirty slip rings. Replace brushes if less than

1/4 in. (6 mm) long. If brushes and slip rings are in good condition, disassemble and

perform rotor test as outlined under “Component Testing - Rotor” following.

72784

a-Excitation Wire - PURPLE

b-Sensing Wire - RED/PURPLE

c-Tie Bar

d-Voltmeter (0-20 Volts)

e-Ground

SENSING CIRCUIT

1. Unplug RED/PURPLE lead from voltage regulator.

2. Connect positive (+) voltmeter lead to RED/PURPLE lead and negative (–) voltmeter

lead to ground terminal.

3. Voltmeter should indicate battery voltage. If battery voltage is not present, check sens-

ing circuit RED/PURPLE lead for loose or dirty connection or damaged wiring.

72786

a-Output Wire - ORANGE

b-Excitation Wire - PURPLE

c-Sensing Wire - RED/PURPLE

d-Voltmeter (0-20 Volts)

e-Ground

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-10 90-861329--1 MARCH 1999

Current Output Test

Perform this test to check if alternator is capable of producing rated current output, using

a 0-50 amp DC ammeter.

WARNING

Be sure that engine compartment is well-ventilated and that there are no gasoline

vapors present (during the test) to prevent the possibility of an explosion and/or a

fire, should a spark occur.

1. Disconnect negative (–) battery cable from battery.

2. Disconnect ORANGE lead from alternator output terminal and connect ammeter in

series between lead and output terminal. Connect positive (+) side of ammeter toward

output terminal.

3. Reconnect negative battery cable.

4. Remove coil wire from distributor cap tower and ground it to block. Turn on all accesso-

ries and crank engine over with starter motor for 15-20 seconds.

5. Turn off accessories and reinstall coil wire. Start engine and adjust engine speed to

1500-2000 rpm. Quickly observe ammeter. Reading should be at least 30 amps.

6. If reading is low, stop engine and connect a jumper wire between alternator output termi-

nal and regulator terminal. Repeat Steps 4 and 5.

7. If reading is now within specifications, diodes are faulty. Disassemble alternator and

replace rectifier as explained under “Alternator Repair,” following, to determine if fault

is in regulator or alternator.

8. If reading is still low with jumper wire connected, perform “Voltage Output Test,” follow-

ing, to determine if fault is in regulator or alternator.

72787

a-Output Wire - ORANGE

b-Ammeter (0-50 Amps)

c-Jumper Lead

d-Regulator Lead

e-Ground

f-Output Lead (Orange)

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-11

Voltage Output Test

Perform this test to determine if voltage regulator is operating correctly, using a 0-20 volt DC

voltmeter.

IMPORTANT: Battery MUST BE fully charged (1.260 or above specific gravity) to

obtain proper voltage reading in this test. If necessary, charge battery with a battery

charger or allow engine to run a sufficient length of time to fully charge battery before

taking reading.

1. Connect positive (+) voltmeter lead to positive (RED) battery terminal and negative (–)

voltmeter lead to negative (BLACK) terminal.

2. Start engine and run at fast idle until engine reaches normal operating temperature.

Adjust engine speed to 1500-2000 rpm and observe voltmeter for highest reading.

Reading should be between 13.9 and 14.7 volts.

3. If reading is high, check for a loose or dirty regulator ground lead connection. If connec-

tion is good (and sensing circuit checked out good in “Circuitry Test”), voltage regulator

is faulty and must be replaced. Be sure to disconnect battery cables before attempting

to remove regulator.

72788

a-Output Wire - ORANGE

b-Excitation Wire - PURPLE

c-Sensing Wire - RED/PURPLE

d-Voltmeter (0-20 Volts)

e-Ground

WARNING

Be sure that engine compartment is well-ventilated and that there are no gasoline

vapors present (during the next steps) to prevent the possibility of an explosion

and/or fire, should a spark occur.

CAUTION

DO NOT allow tie jumper wire to contact alternator end frame (in next step), as recti-

fier and diode assembly may be damaged.

4. Remove four nuts holding excitation and sensing wires and Phillips screw. Remove

regulator cover and install wires and nuts for testing. Connect a jumper wire from the

ground stud to the brush terminal on the lower right- hand side of the brush assembly.

Restart engine and gradually increase engine speed to 1500 rpm while observing

voltmeter. DO NOT allow voltage to exceed 16 volts.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-12 90-861329--1 MARCH 1999

5. If a voltmeter reading of 14.5 volts or above is now obtained, voltage regulator is faulty

and must be replaced. If voltmeter reading is below 14.5 volts, inspect brushes and slip

rings for wear, dirt or damage. If brushes and slip rings are good, alternator is faulty

internally. Disassemble alternator and test components, as outlined under “Alternator

Repair,” following.

72971

a-Ground

b-Brush/Regulator Assembly

c-Brush Terminal

d-Jumper Wire

Alternator Repair

Removal

1. Disconnect negative (–) battery cable from battery.

2. Disconnect wiring harness from alternator.

3. Remove alternator brace-to-alternator attaching bolt, washer(s) and spacer (if used).

4. Loosen alternator brace-to-engine attaching bolt and alternator mounting bolt, then

pivot alternator inward and remove alternator drive belt.

5. Remove alternator mounting bolt, washers (if used), spacer and nut, and remove

alternator.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-13

Exploded View

72276

12 13

1-Screws (3)

2-Nut (9)

3-Flat Washer (4)

4-Sensing Wire (RED / PURPLE)

5-Excitation Wire (PURPLE)

6-Cover

7-Tie Strap

8-Rubber Gasket

9-Condenser

10 - Insulator

11 - Bolt (4)

12 - End Frame (Rear)

13 - Cap (2)

14 - Brush / Regulator Assembly

15 - Rectifier Assembly

16 - Flat Washer

17 - Screw

18 - Stator

19 - Rotor And Slip Ring

20 - Retaining Plate

21 - Front Bearing

22 - End Frame (Front)

23 - Screw (3)

24 - Fan Spacer

25 - Fan

26 - Pulley Spacer

27 - Pulley

28 - Lockwasher

29 - Nut

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-14 90-861329--1 MARCH 1999

Disassembly

IMPORTANT: The following instructions are for complete disassembly and overhaul

of the alternator. In many cases, however, complete disassembly of alternator is not

required and, in those cases, it is necessary only to perform the operations required

to repair or replace the faulty part.

1. Mount alternator in a vise so that rear end frame is facing you.

2. Disconnect regulator leads from terminals on rear end frame. Remove four nuts, Phillips

head screw and two regulator leads. Then pull regulator cover away from rear end

frame.

72963

a-Regulator Leads

b-Nuts (4)

c-Phillips Head Screw

d-Regulator Cover

3. Remove stud cover insulator, two nuts and tie strap from brush/regulator assembly.

4. Remove two brush/regulator attaching screws and remove brush/regulator assembly.

72823

a-Screws

b-Brush/Regulator Assembly

c-Stud Cover Insulator

d-Tie Strap

5. Scribe a mark on rear end frame, stator and front end frame to ensure proper

reassembly later.

6. Remove four screws which secure end frames and stator together.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-15

IMPORTANT: DO NOT insert screwdriver blades more than 1/16in. (1.5 mm) into open-

ings (in next step), as stator windings may be damaged.

7. Separate rear end frame and stator assembly from front end frame and rotor assembly

using two thin blade screwdrivers (positioned 180 degrees apart from one another) at

the locations shown. Use the two slots shown to initially separate units.

72824

a-DO NOT Insert Screwdriver Blades More Than 1/16in. (1.5 mm) Into Slots

b-Rear End Frame

c-Stator

d-Front End Frame

e-Scribe Marks

8. Place rear end frame and stator assembly on the bench with stator downward. Be sure

that bench is clean and free of metal chips. Remove nuts, washers, insulators and con-

denser from output and ground studs.

9. Turn end frame over (stator upward) and remove one Phillips head screw which secures

rectifiers to end frame.

72826

a-Rectifier Assembly

b-Phillips Head Screw

10. Separate stator and rectifier assembly from rear end frame using screwdriver slots.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-16 90-861329--1 MARCH 1999

11. Unsolder the three stator leads from the rectifier heat sink. Place a needle nose pliers

on diode terminal between solder joint and diode body to help prevent heat damage to

diodes. Unsolder joints as quickly as possible and allow diode terminal to cool before

removing pliers.

72827

a-Heat Sink

b-Stator Leads (3)

IMPORTANT: With alternator disassembled to this point, stator, rectifier, diodes, and

rotor may be tested, as explained under “Component Testing,” following.

IMPORTANT: DO NOT clamp vise on rotor pole pieces when removing pulley nut (in

next step), as pole pieces may be distorted.

12. Remove pulley retaining nut by clamping pulley in a vise (using an oversize V-belt or

protective jaws to protect pulley) and turning nut counterclockwise with a 7/8 in. wrench.

Remove lockwasher and slide pulley and fan from shaft. If pulley is difficult to remove,

it may be necessary to use a universal puller.

72828

a-7/8 in. Wrench

b-Over-Sized V-Belt To Protect Pulley

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-17

13. Remove the three Phillips head screws and lockwashers which secure the front bearing

retaining plate.

72829

a-Phillips Head Screws and Lockwashers

b-Front Bearing Retaining Plate

14. Remove front bearing from front end frame using an arbor press and a suitable size

mandrel. Discard bearing.

72830

a-Press

b-Mandrel

c-Bearing

15. If rotor slip rings or rear bearing requires replacement, entire rotor must be replaced.

Parts cannot be purchased separately.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-18 90-861329--1 MARCH 1999

Cleaning and Inspection

1. Clean all parts with a clean, soft cloth. DO NOT use solvent, or electrical components

may be damaged.

2. Inspect the following parts for wear and damage:

a. Brush/regulator assembly - inspect for cracked casing, damaged brush leads,

poor brush lead solder connections, weak or broken brush springs or worn brushes.

Replace brush set if brushes are less than 1/4in. (6 mm) long.

b. Rotor - inspect for stripped threads, scuffed pole piece fingers or damaged bearing

surfaces (because of bearing turning on shaft).

c. Rotor-slip rings - clean slip rings with 400 grain (or finer) polishing cloth while spin-

ning rotor in a lathe. Blow off dust with compressed air. Inspect slip rings for grooves,

pits, flat spots or out-of-round [.002in. (0.051 mm) maximum] and replace rotor, if

present.

d. Rotor shaft and front end bearings - inspect for damaged seals, lack of lubrica-

tion, discoloration (from overheating) and excessive side or end play. Bearing

should turn freely without binding or evidence of rough spots.

e. Stator - inspect for damaged insulation or wires; also inspect insulating enamel for

heat discoloration, as this is usually a sign of a shorted or grounded winding or a

shorted diode.

f. Front and rear end frames - inspect for cracks, distortion, stripped threads or wear

in bearing bore (from bearing outer race spinning in bore). End frame(s) MUST BE

replaced, if bearing has spun. Also, inspect bearing retainer recess in front end

frame for damage.

g. Fan - inspect for cracked or bent fins, broken welds (bi-rotational fan only) or worn

mounting hole (from fan spinning on shaft).

h. Pulley - inspect pulley mounting bore end for wear. Inspect drive surface of pulley

sheaves for trueness, excessive wear, grooves, pits, nicks and corrosion. Repair

damaged surfaces, if possible, with a fine file and a wire brush or replace pulley, if

beyond repair. Drive surfaces MUST BE perfectly true and smooth or drive belt wear

will be greatly accelerated.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-19

Component Testing

ROTOR

1. Test rotor field circuit for opens, shorts or high resistance (Test 1), using an ohmmeter

(set on R x1 scale), as follows:

72831

Testing Rotor Field Circuit

a-Test 1

b-Test 2

a. Connect one ohmmeter lead to each slip ring.

b. Ohmmeter reading should be 4.2 to 5.5 ohms with rotor at room temperature

70-80°F (21-26°C).

c. If reading is high or infinite (no meter movement), high resistance or an open exists

in the field circuit. Check for poor connections between field winding leads and slip

ring terminals. If cause for open or high resistance cannot be found, connect ohm-

meter directly to slip ring terminals. If correct reading is now obtained, or if reading

is still high or infinite, replace complete rotor assembly.

d. If reading is low, a short exists in the field circuit. Inspect slip rings to be sure that

they are not bent and touching outer slip ring. Also, be sure that excess solder is not

shorting terminals to aft slip ring. If cause for short cannot be found, unsolder field

winding leads from slip ring terminals and connect ohmmeter directly to leads. If cor-

rect reading is now obtained, or if reading is still low, slip rings and rotor field windings

are shorted, and complete rotor assembly must be replaced.

73112

a-Field Winding Leads

b-Slip Rings

c-Rotor Shaft

d-Pole Pieces

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-20 90-861329--1 MARCH 1999

2. Test rotor field circuit for grounds (Test 2), using an ohmmeter (set on R x1 scale) as

follows:

a. Connect one lead of ohmmeter to either slip ring and the other lead to rotor shaft or

pole pieces.

b. Meter should indicate no continuity (meter should not move).

c. If continuity does exist, complete rotor assembly must be replaced.

IMPORTANT: If alternator has output at low speeds, but no output at high speeds,

rotor field winding may be shorting or grounding out, due to centrifugal force.

Replace rotor if all other electrical components test good.

STATOR

IMPORTANT: Stator leads MUST BE disconnected from rectifier for this test.

1. Test stator for grounds (Test 1), using an ohmmeter (set on R x1 scale) as follows:

a. Connect one lead of ohmmeter to one of the stator leads and the other lead to stator

frame. Be sure that lead makes good contact with frame.

b. Meter should indicate no continuity (meter should not move). If continuity does exist,

stator is grounded and must be replaced.

2. Test for opens in stator (Test 2), using an ohmmeter (set on R x1 scale) as follows:

a. Connect ohmmeter between each pair of stator windings (three different ways).

b. Continuity should be present in all three cases (meter should move). If it does not,

one or more of the windings are open and stator must be replaced.

72833

b b

Testing Stator

a-Test 1

b-Test 2

3. A short in the stator is difficult to detect without special equipment, because of the low

windings resistance. If all other electrical components test out good, and alternator fails

to produce rated output, stator probably is shorted and should be replaced. Also,

examine stator for heat discoloration, as this usually is a sure sign of a short.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-21

RECTIFIER AND DIODE ASSEMBLY

NOTE: Failure of any component in tests following will require replacement of entire rectifier

assembly.

NEGATIVE (–) RECTIFIER

IMPORTANT: Rectifier MUST BE disconnected from stator for this test.

CAUTION

DO NOT use a test instrument with more than a 12 volt source (in the following test),

as rectifier may be damaged.

1. Connect one lead of an ohmmeter (set on R x1 scale) to negative (–) rectifier heat sink

and the other lead to one of the rectifier terminals. Note the reading.

2. Reverse leads and again note reading.

3. Meter should indicate a high or infinite resistance (no meter movement) when con-

nected one way and a low reading when connected the other. If both readings are high

or infinite, rectifier is open. If both readings are low, rectifier is shorted.

4. Repeat Steps 1 through 3 for two other rectifiers in heat sink.

5. Replace assembly if any of the rectifiers is shorted or open.

72147

a-Heat Sink

b-Rectifier Terminal

c-Test These Two Rectifiers in Same Manner

POSITIVE (+) RECTIFIER AND DIODES

CAUTION

DO NOT use a test instrument with more than a 12 volt source (in the following test),

as rectifier may be damaged.

1. Connect one lead of an ohmmeter (set on R x1 scale) to 1/4in. stud on positive (+)

rectifier heat sink and the other lead to one of the rectifier terminals. Note the meter

reading.

2. Reverse leads and again note reading.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-22 90-861329--1 MARCH 1999

3. Meter should indicate a high or infinite resistance (no meter movement) when con-

nected one way and a low reading when connected the other. If both readings are high

or infinite, rectifier is open. If both readings are low, rectifier is shorted.

4. Repeat Steps 1 through 3 for two other rectifiers in heat sink.

72834

a-Stud

b-Rectifier Terminal

c-Repeat Test Between These Terminals And Stud

5. Replace assembly if any one of the rectifiers is shorted or open.

6. Connect one lead of an ohmmeter (set on R x1) to the common side of the diode and

the other lead to the other side, of one of the three diodes.

72148

a-Common Side of Diode Circuit Board

b-Repeat Test for These Two Diodes

7. Reverse leads and again note reading.

8. Meter should indicate a high or infinite resistance (no meter movement) when

connected one way and a low reading when connected the other. If both readings are

high or infinite, diode is open. If both readings are low, diode is shorted.

9. Repeat Steps 6 through 8 for the other two diodes.

10. Replace rectifier assembly if any one of the diodes is shorted or open.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-23

CONDENSER

1. Using magneto analyzer and accompanying instructions, perform the following

condenser tests:

a. Condenser Capacity Test (must be .5 mfd).

b. Condenser Short or Leakage Test.

c. Condenser Series Resistance Test.

2. Replace condenser if test results are not within specifications.

Reassembly

1. Install new front bearing into front end frame bearing bore using an arbor press. If neces-

sary, use a bearing driver that contacts outer race only.

72835

a-Press

b-Mandrel

2. Install front bearing retaining plate using three Phillips head screws and lockwashers.

72829

a-Phillips Head Screws and Lockwashers

b-Front Bearing Retaining Plate

3. Slide front end frame over rotor.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-24 90-861329--1 MARCH 1999

IMPORTANT: DO NOT clamp vise on rotor pole pieces when tightening pulley nut (in

next step), or pole pieces may be distorted.

4. Slide fan spacer onto rotor shaft. Install fan, pulley, lockwasher and nut on shaft. Clamp

pulley in a vise, using protective jaws or an old oversize V-belt to protect pulley, and

torque nut to specifications. Tighten vise only enough to allow tightening of nut, as

excessive tightening may distort pulley.

5. Assemble stator to rectifier by soldering the three leads to the three rectifier terminals.

72826

a-Stator Lead Connections

NOTE: Be sure to connect leads to their original positions.

6. Install assembled stator and rectifier assembly into rear end frame, aligning scribe

marks on each (scribed during disassembly), and install Phillips head screw and washer

to retain.

IMPORTANT: The insulating washers MUST BE installed as shown or damage to the

alternator will result.

7. Position stator down with rear end frame up and reinstall insulators, nuts and condenser.

72561

a-Insulators (3)

b-Nuts (5) (One Removed)

c-Condenser

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-25

8. Position rear end frame and stator assembly over front end frame and rotor assembly

and align scribe marks on each (scribed during disassembly). Hand-press end frames

together, then install four screws. Tighten screws securely.

72561

a-Rear End Frame

b-Stator

c-Front End Frame

d-Scribe Marks

e-Insert Screws (4) (Two Hidden)

9. Depress brushes flush with top of brush holder and insert a #54 drill bit or smaller

(.050in.) into hole in brush holder to hold brushes compressed during reassembly.

72836

a-Drill Bit

NOTE: Shown with rubber gasket removed for clarity.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-26 90-861329--1 MARCH 1999

10. Install brush/regulator assembly in rear end frame cavity and secure with two mounting

screws, as shown. Tighten screws securely. Remove drill bit to release brushes against

slip rings.

72837

a-Brush/Regulator Assembly

b-Mounting Screws

11. Install tie strap to rectifier stud and stud on brush/rectifier assembly. Tighten nuts

securely.

72823

a-Studs

b-Tie Strap

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-27

12. Install cover with one Phillips head screw and two nuts. Install two leads with nuts.

72963

a-Phillips Head Screw

b-Nuts (4)

c-Leads

13. Install insulator caps.

72078

a-Insulator Caps

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-28 90-861329--1 MARCH 1999

Installation

1. Position alternator in mounting bracket and install mounting bolt, washers (if used),

spacer and nut. Place washers (if used), on each side of spacer. DO NOT tighten

securely at this time.

2. Fasten alternator brace to alternator with bolt, washers and spacer (if used). DO NOT

tighten bolt at this time.

3. Position alternator drive belt on pulleys and adjust tension as explained under “Drive

Belt Tension Adjustment.”

4. Reconnect wiring harness to alternator and negative battery cable to battery.

72838

a-Excitation Lead - PURPLE

b-Sensing Lead - RED/PURPLE

c-Ground Lead - BLACK

d-Output Lead - ORANGE

IMPORTANT: Alternators used on MerCruiser engines ARE NOT equipped with an

isolation diode.

CAUTION

Follow battery isolator manufacturer’s instructions for wire gauge. Battery isolator

installation must conform to BIA Low Voltage Wiring Standard No. 125-79.

NOTE: MerCruiser engines equipped with a 3-wire, belt driven alternator can use a battery

isolator.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-29

Batteries

Battery Cables

Select proper size positive (+) and negative (–) battery cables, using chart. Battery should

be located as close to engine as possible.

IMPORTANT: Terminals must be soldered to cable ends to ensure good electrical

contact. Use electrical grade (resin flux) solder only. Do not use acid flux solder as

it may cause corrosion and a subsequent failure.

Cable Length

Cable Gauge

Up to 3 - 1/2 ft (1.1m) 4 (25 mm

)

3-1/2 - 6 ft (1.1-1.8m) 2 (35mm

)

6 ft - 7-1/2 ft (1.8-2.3m) 1 (50mm

)

7-1/2 - 9-1/2 ft (2.3-2.9m) 0 (50mm

)

9-1/2 - 12 ft (2.9-3.7m) 00 (70mm

)

12 - 15 ft (3.7-4.6m) 000 (95mm

)

15 - 19 ft (4.6-5.8m) 0000 (120m

)

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-30 90-861329--1 MARCH 1999

Mando 55 Amp Alternator

Identification

72078

Mando 55 Amp Alternator

a-Excitation Wire - PURPLE

b-Sensing Wire - RED/PURPLE

c-Mando Part Number (Hidden In This View)

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to mini-

mize risks of fire and explosion.

Use of replacement electrical, ignition or fuel system components, which do not

comply with these rules and regulations, could result in a fire or explosion hazard

and should be avoided.

Specifications

Description Specification

Excitation Circuit 1.3-2.5 Volts

Current Output 50 Amp Minimum

Voltage Output 13.9-14.7 Volts

Condenser Capacity .5 MFD

Minimum Brush Length 1/4in. (6mm)

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-31

Tools

Description Part Number

Bearing Removal and Installation Kit 91-31229A7

Magneto Analyzer 91-76032

Universal Puller Plate 91-37241

Multi-Meter/DVA Tester 91-99750A1

Ammeter (0-50 Amps) Obtain Locally

Lubricants/Sealants/Adhesives

Description Part Number

Quicksilver Liquid Neoprene 92-27511--3

Torque Specifications

Fastener Location lb-in. lb-ft Nm

End Frame Screws 55 6.5

Brush Setscrews 18 1.5

Regulator Mounting Screws 43 4.5

Regulator Leads 25 2.5

Ground Terminal Nut 25 2.5

Pulley Nut 42 58

Alternator Brace to Alternator 192 28

Alternator Brace to Block 30 40

Alternator to Mounting Bracket 35 48

Alternator Mounting Bracket 30 41

V-Belt Tension (Note) Depress 1/2in. (13mm)

NOTE: Depress belt with thumb at midway point between circulating pump pulley and

alternator.

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-32 90-861329--1 MARCH 1999

Battery Isolator Diagram

72934

a-Circuit Breaker

b-Harness Connector

c-Alternator

d-Starter

e-Cranking Battery

f-Ground Stud

g-Auxiliary Battery

h-Isolator

1-Disconnect Orange Wire From Alternator “Batt” Terminal. Splice Sufficient

Gauge Wire To The Orange Wire And Connect As Shown.

2-8 Gauge Minimum

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-33

Mando 65 Amp Alternator

Identification

72078

Mando 65 Amp Alternator

a-Excitation Wire - PURPLE

b-Sensing Wire - RED/PURPLE

c-Mando Part Number (Hidden In This View)

Replacement Parts Warning

WARNING

Electrical, ignition and fuel system components on your MerCruiser are designed

and manufactured to comply with U.S. Coast Guard Rules and Regulations to mini-

mize risks of fire and explosion.

Use of replacement electrical, ignition or fuel system components, which do not

comply with these rules and regulations, could result in a fire or explosion hazard

and should be avoided.

Specifications

Description Specification

Excitation Circuit 1.3 to 2.5 Volts

Current Output 60 Amp. Min.

Voltage Output 13.9 to 14.7 Volts

Min. Brush Length 1/4in. (6 mm)

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-34 90-861329--1 MARCH 1999

Tools

Description Part Number

Bearing Removal and Installation Kit 91-31229A7

Universal Puller Plate 91-37241

Multi-Meter/DVA Tester 91-99750A1

Ammeter (0-100 Amp) Obtain Locally

Lubricants/Sealants/Adhesives

Description Part Number

Quicksilver Liquid Neoprene 92-27511--3

Torque Specifications

Fastener Location lb-in. lb-ft Nm

End Frame Screws 55 5.5

Brush Setscrews 18 1.5

Regulator Mounting Screws 42 4.2

Regulator Leads 25 2.5

Ground Terminal Nut 25 2.5

Pulley Nut 42 57

Alternator to Mounting Bracket 35 48

Alternator Mounting Bracket 30 41

Belt Tension See Note

NOTE: Belt deflection is to be measured on the belt at the location that has the longest

distance between two (2) pulleys. Normally this location is between the power steering

pump and the belt adjustment pulley. This location will be different on engines with closed

cooling or models without power steering.

NOTE: Depress belt with thumb at midway point between circulating pump pulley and

alternator.

INDEX

CHARGING SYSTEM

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4C-35

Exploded View

72276

12 13

1-Screws (3)

2-Nut (9)

3-Flat Washer (4)

4-Sensing Wire (RED / PURPLE)

5-Excitation Wire (PURPLE)

6-Cover

7-Tie Strap

8-Rubber Gasket

9-Condenser

10 - Insulator

11 - Bolt (4)

12 - End Frame (Rear)

13 - Cap (2)

14 - Brush / Regulator Assembly

15 - Rectifier Assembly

16 - Flat Washer

17 - Screw

18 - Stator

19 - Rotor And Slip Ring

20 - Retaining Plate

21 - Front Bearing

22 - End Frame (Front)

23 - Screw (3)

24 - Fan Spacer

25 - Fan

26 - Pulley Spacer

27 - Pulley

28 - Lockwasher

29 - Nut

INDEX

CHARGING SYSTEM SERVICE MANUAL NUMBER 26

Page 4C-36 90-861329--1 MARCH 1999

THIS PAGE IS INTENTIONALLY BLANK

INDEX

INSTRUMENTATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-1

ELECTRICAL SYSTEM

Section 4D - Instrumentation

Table of Contents

Identification 4D-2. . . . . . . . . . . . . . . . . . . . . . . . . .

Special Information 4D-3. . . . . . . . . . . . . . . . . . . .

Lighting Options 4D-3. . . . . . . . . . . . . . . . . . . .

Gauges 4D-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oil, Fuel and Temperature 4D-5. . . . . . . . . . .

Battery Gauge 4D-7. . . . . . . . . . . . . . . . . . . . .

Cruiselog Meter 4D-8. . . . . . . . . . . . . . . . . . . .

Vacuum Gauge 4D-8. . . . . . . . . . . . . . . . . . . . .

Speedometer 4D-9. . . . . . . . . . . . . . . . . . . . . .

Tachometer 4D-9. . . . . . . . . . . . . . . . . . . . . . . .

Gauge Replacement 4D-9. . . . . . . . . . . . . . . .

Senders 4D-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oil Pressure 4D-10. . . . . . . . . . . . . . . . . . . . . .

Water Temperature Sender 4D-11. . . . . . . . .

Fuel Tank Sender 4D-14. . . . . . . . . . . . . . . . . . . .

Flange Type 4D-14. . . . . . . . . . . . . . . . . . . . . .

Capsule Type 4D-15. . . . . . . . . . . . . . . . . . . . .

Switches 4D-16. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ignition Key Switch 4D-16. . . . . . . . . . . . . . . .

Audio Warning System 4D-17. . . . . . . . . . . . . . . .

Buzzer 4D-17. . . . . . . . . . . . . . . . . . . . . . . . . . .

Oil Pressure Switch 4D-18. . . . . . . . . . . . . . . .

Water Temperature Switch 4D-18. . . . . . . . . .

Index

INSTRUMENTATION SERVICE MANUAL NUMBER 26

Page 4D-2 90-861329--1 MARCH 1999

Identification

One of three distinct lines (Series) of Quicksilver gauges may be installed (if equipped with

Quicksilver gauges). Aside from different gauge face appearances and styling, the back of

the gauges and wiring connections are different as shown.

72746

Back of Commodore and International Series Gauge - Typical

72965

Back of QSI Series Gauge - Typical

IndexIndex

INSTRUMENTATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-3

Special Information

Lighting Options

COMMODORE AND INTERNATIONAL SERIES

These gauges may be wired so that the illumination lighting is provided from the ignition

switch or a separate instrumentation lighting switch.

By removing contact strip “I” from between + terminal and the screw as shown following, and

supplying a separate +12 V power supply to the screw connection, illumination lights can

be operated independent of ignition switch.

72966

Ignition Switch Lighting Circuit

a-+12 V Power Supply From Ignition Switch

b-Contact Strip “I”

c-Screw Connection

72967

Separate Instrumentation Lighting Circuit Wiring

a-12 Volt Power Supply From Separate Instrumentation Lighting Circuit

b-Contact Strip “I” - Removed

c-Screw Connection

IndexIndex

INSTRUMENTATION SERVICE MANUAL NUMBER 26

Page 4D-4 90-861329--1 MARCH 1999

QSI SERIES

These gauges are equipped with optional illumination lighting. Light bulb socket can be

removed and contacts can be aligned to be used with ignition switch lighting circuit +12 V

or separate instrumentation lighting circuit LT.

IMPORTANT: Light socket must be removed from gauge and turned counterclock-

wise (facing back of gauge) when adjusting to desired setting. Turning socket while

still installed in gauge could result in damage to gauge or socket.

NOTE: For different lighting effects, colored sleeves are available through the Quicksilver

Accessories and can be assembled to the bulb.

72968

Ignition Switch Lighting Circuit Position

a-+12 V Power Supply From Ignition Switch

72969

Separate Instrumentation Lighting Circuit Position

a-+12 V Power Supply From Ignition Switch

b-+12 V Power Supply From Separate Instrumentation Lighting Circuit

IndexIndex

INSTRUMENTATION

SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-5

Gauges

Oil, Fuel and Temperature

IMPORTANT: If testing proves gauge to be defective, it must be replaced as there is

no repair available.

TESTING

1. Turn ignition switch to OFF.

2. Remove wire from terminal S (SEND).

72965

Typical

a-Sender Terminal

3. Turn ignition switch to RUN. Gauge being tested must be at position A.

72747

Typical Position A

4. Turn ignition switch to OFF.

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Page 4D-6 90-861329--1 MARCH 1999

5. Connect jumper wire from terminal G (GND) to terminal S (SEND).

72748

Typical

6. Turn ignition switch to RUN.

7. Indicator needle of gauge being tested must read at position B. If not, replace gauge.

72749

Typical Position B

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SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-7

Battery Gauge

TESTING

1. Remove cables from battery and fully charge battery.

2. Connect negative (–) jumper lead from battery to gauge terminal G (GND).

3. Connect positive (+) jumper lead from battery to gauge terminal I or +12 V.

72750

Typical

4. Check gauge reading; if not as shown replace gauge.

72751

Typical

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Page 4D-8 90-861329--1 MARCH 1999

Cruiselog Meter

TESTING

1. Connect jumper wire from negative (–) battery terminal to negative (–) gauge terminal.

2. Connect jumper wire from positive (+) battery terminal to positive (+) gauge terminal.

72752

3. Observe gauge run indicator. If indicator is turning, gauge is operable; if not, replace

gauge.

72753

a-Indicator

Vacuum Gauge

TESTING

1. Disconnect vacuum hose from engine. Connect service vacuum gauge to engine and

record engine vacuum readings at idle, 1000, 2000 and 3000 rpm. Reconnect vacuum

hose and compare vacuum gauge readings (at specified rpm) with service gauge read-

ings. Readings should be within 3 inches of vacuum of each other.

IMPORTANT: Make sure that vacuum hose between gauge and engine is not leaking

and that all connections are tight.

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SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-9

Speedometer

TESTING

IMPORTANT: When testing speedometer gauge for accuracy, the air supply used for

the test must be regulated to the specified air pressure. Do not apply excessive air

pressure to speedometer gauge.

1. Apply air pressure directly to speedometer gauge (specified in chart) and note gauge

reading. Light tapping of pressure gauge is required during accuracy check.

2. If gauge readings are not within specifications, gauge is defective.

CALIBRATION CHART

Air Pressure Gauge psi Speedometer Gauge MPH (km/Hr)

5.3 20 + 1 (32 + 1.6)

27.8 45 + 1 (72 + 1.6)

Tachometer

TESTING

1. Connect a service tachometer to engine and compare readings.

2. Replace if not within specifications.

Tachometer Type Allowable Range

6000 rpm + 150 rpm

8000 rpm + 200 rpm

Gauge Replacement

1. Disconnect battery cables from battery.

2. Remove wires from back of gauge.

3. Remove hoses (vacuum, speedometer gauge).

4. Disconnect light socket.

5. Remove holding strap and remove gauge.

6. Position gauge assembly in appropriate mounting hole.

7. Install holding strap and nuts. Tighten nuts evenly and securely.

IMPORTANT: Do not distort case or bracket by overtightening.

8. Connect ground (BLACK) wire to ground terminal, if gauge is not mounted in metal

panel.

9. Connect other wires to gauge as shown in SECTION 4E.

10. Connect hoses (vacuum, speedometer gauges).

11. Install gauge light socket.

12. Coat all terminals with Quicksilver Liquid Neoprene.

13. Reconnect battery cables to battery.

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Page 4D-10 90-861329--1 MARCH 1999

Senders

Oil Pressure

TESTING

IMPORTANT: Use following test procedure for checking accuracy of oil pressure

sender only. If oil pressure gauge indicates zero oil pressure, refer to SECTION 4C

“Troubleshooting.”

1. Remove wire from sender terminal.

2. Connect ohmmeter between sender terminal and sender case. Check ohms reading

without engine running (zero pressure), then check reading with engine running. Com-

pare oil pressure and ohms readings as shown in following chart:

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a-Positive Lead

b-Negative Lead

c-Wire Removed

d-Oil Pressure Sender

Ohms Reading

Oil Pressure (psi)

Single Dual

0 227-257 113.5-128.5

20 142-162.5 71-81.3

40 91.7-113.6 45.9-56.8

80 9-49 11-24.5

DUAL STATION SENDER IDENTIFICATION

Sender will have 3353-AM stamped on hex of sender.

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SERVICE MANUAL NUMBER 26

90-861329--1 MARCH 1999 Page 4D-11

Water Temperature Sender

There is no accurate test that can be done without special equipment. Install new sender.

TESTING

1. Connect an ohmmeter between temperature sender terminal (+) and hex (case) for

ground (–) as shown.

72768

a-Ohmmeter Leads

b-Water Temperature Sender

WARNING

The following test involves the use of intense heat. Failure to follow appropriate

procedures or warnings can cause burns which can result in severe personal injury.

While performing the following test, observe these general precautions:

• Wear personal protective clothing such as rubber gloves, a non-flammable

apron, and eye protection - preferably full face shield or safety glasses.

• The appropriate heat source should only be electric. Heat source should be

operated by a qualified person. Be sure to follow all instructions of the

manufacturer of the heat source. The heat source should be checked each time

it is used to be sure it is functioning properly.

• The thermometer used in the test should be a high-temperature thermometer

with a maximum reading of at least 300°F (150°C). Under no circumstances

should the operator allow temperatures to exceed test specifications.

• Perform test only in a well ventilated area.

• Use a suitable container, such as metal, to hold the water. Avoid use of glass

containers unless the operator first confirms for himself/herself that the glass

container is an appropriate high-temperature vessel.

• Because the components will reach high temperatures DO NOT handle materi-

als or components until COMPLETELY cooled.

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Page 4D-12 90-861329--1 MARCH 1999

2. Follow these instructions:

a. With ohmmeter connected as outlined and using suitable container, thermometer

and heat source, suspend sender with tip in water.

b. Heat water and observe thermometer.

c. As temperature rises ohmmeter readings must be within the ranges specified for

each temperature (see chart below).

d. Turn heat source off. Allow water and components to cool.

NOTE: While water cools you may recheck ohmmeter readings.

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a-Suitable Container

b-Thermometer

c-Heat Source

d-Water Temperature Sender

e-Ohmmeter Leads

Water Temperature Ohms Reading

140°F (60°C) 121-147

194°F (90°C) 47-55

212°F (100°C) 36-41

3. Replace sender if ohmmeter readings are other than as shown for each temperature.

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INSTALLATION

1. Apply Loctite Pipe Sealant with Teflon to threads of temperature sender.

2. Install sender in thermostat housing and tighten securely.

3. Connect TAN wire and coat with liquid neoprene.

a-TAN Wire

b-Water Temperature Sender

4. Refill closed cooling system with approved coolant as outlined in SECTION 6B.

DUAL STATION SENDER IDENTIFICATION

Sender will have 362-BC stamped on hex.

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Fuel Tank Sender

Flange Type

TESTING

1. Disconnect wire from terminal on sending unit and ground wire from sending unit mount-

ing screw.

2. Remove sending unit from fuel tank.

3. Connect ohmmeter between sending unit terminal and sending unit housing.

4. With float arm in FULL position (arm horizontal), ohmmeter should read 30 ohms

5 ohms).

72755

a-Ohmmeter Leads

b-Vertical Float Arm

5. With float arm in EMPTY position (arm vertical) meter should read 240 ohms (+

5 ohms).

Sender is defective if not within specifications.

72756

a-Ohmmeter Leads

b-Vertical Float Arm

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Capsule Type

TESTING

1. Disconnect wire from terminal on fuel tank capsule.

2. Remove two screws and remove capsule assembly.

3. Place a magnet under fuel capsule.

4. Connect ohmmeter between fuel capsule terminal and metal portion of capsule housing.

72757

a-Ohmmeter Leads

b-Capsule Assembly

c-Magnet

5. Turn magnet counterclockwise until fuel capsule indicator reads EMPTY. Ohmmeter

should read 240 ohms (+

5 ohms).

72758

a-Capsule Reading Empty

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Page 4D-16 90-861329--1 MARCH 1999

6. Turn magnet clockwise until fuel capsule indicator reads FULL. Ohmmeter should read

30 ohms (+

5 ohms). Fuel capsule is defective if not within specifications.

72759

a-Capsule Reading Full

Switches

Ignition Key Switch

TESTING

WARNING

Disconnect battery cables from battery before testing ignition key switch with wires

still connected to switch.

1. Before testing key switch, check all fuses and/or circuit breakers in electrical circuit

which could prevent operation of starter.

2. With key switch in OFF position, there should be no continuity between switch terminals.

3. With key switch in RUN position, continuity will exist between switch terminals B to A and

B to I. There should be no continuity between terminal C and any other terminals.

4. With key switch in START, continuity will exist between terminals B to A, B to I and B to

5. If ignition key switch tests bad, unsolder wire connections and remove switch. Test

switch again, as in Steps 2-5, preceding. If switch tests good, wiring in harness is bad.

There should be no continuity between any harness wires with key switch removed.

Switch Terminal Identification

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90-861329--1 MARCH 1999 Page 4D-17

Audio Warning System

Buzzer

WARNING

The following test involves the use of electricity. Failure to follow appropriate pro-

cedures can cause burns or shock which can result in severe personal injury or

death.

TESTING

1. Turn the ignition switch to the ON position without cranking the engine. The horn will

sound if the system is working correctly.

2. If horn does not sound:

a. Connect jumper wires as shown.

b. If horn does not sound, replace it.

3. If horn worked in Step 3:

a. Connect jumper wires as shown.

b. Repeat Step 2.

c. If horn sounds, problem is in TAN/BLUE wire back to engine or switches on engine.

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Page 4D-18 90-861329--1 MARCH 1999

Oil Pressure Switch

Refer to SECTION 4E for switch locations. Switch is normally closed.

TESTING

1. Remove wire from sender terminal.

2. Connect continuity meter between sender terminal and sender hex. (Sender shown

removed for clarity.)

72764

3. With engine not running, meter should indicate full continuity.

4. Start engine. With engine running and engine oil pressure above 6 psi (41 kPa), meter

should indicate NO continuity.

SWITCH IDENTIFICATION

Switch has 364-AF stamped on hex of sender.

Water Temperature Switch

TESTING

1. Connect an ohmmeter between water temperature switch terminal (+) and hex (case)

for ground (–) as shown.

72765

a-Ohmmeter Leads

b-Water Temperature Switch

2. Switch should read no continuity.

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90-861329--1 MARCH 1999 Page 4D-19