Onan B43E, B48G, B43G Service Manual

Service

Manual

965-0757

WE

(Spec

WG

(SF

B48G

(Spec

6-88

Prmlsd

in

USA

A-D)

A-G)

_--

45

-..

6

.-

-

I

Safety

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by any means, is strictly prohibited.

Precautions

It is recommended that you read your engine manual and become thoroughly acquainted with your equipment before

you

start the engine.

This symbol if used warns of immediate hazards which will

severe personal injury or death.

This symbol refers

[AWARNING!

severe personal injury

unsafe practice which can result in

or

death.

This symbol refers

'

personal injury or product or properiy damage.

unsafe practice which can result in

to

Fuels, electrical equipment, batteries, exhaust gases and moving parts present potential hazards that can result in serious, personal injury. Take care in following these recommended procedures.

All

local, state and federal codes should

be consulted and complied with.

This engine

@@!@

Use

of

this engine in aircraft can result in engine failure

tended for

Is

not designed or in-

use

in any type of aircraft.

and causes serious personal injury or death.

General

0

Provide appropriate fire extinguishers and install them in convenient locations. Use an extinguisher rated ABC by NFPA.

0

Make sure that all fasteners on theenginearesecureand accurately torqued. Keep guards in position over fans, driving belts, etc.

0

If

it is necessary

to

make adjustments while the engine is running, use extreme caution when close moving parts, etc.

Protect Against Moving Parts

0

Do

not wear loose clothing in the vicinity

such as

Pi0

shafts, flywheels, blowers, couplings, fans,

belts, etc.

result

8

hazard or

a

hazard or

to

hot exhausts,

of

moving parts,

in

Fuel

System

DO

NOT fill fuel tanks while engine is running.

DO

NOT

smoke or use an open flame in the vicinity

of

the engine or fuel tank. Internal combustion engine fuels are highly flammable.

Fuel lines must be of steel piping, adequately secured, and free from leaks. Piping at the engine should be approved flexible line.

Do

not use copper piping for flexible lines as copper will work harden and become brittle enough

to

break.

Be sure all fuel supplies have a positive shutoff valve.

Exhaust

System

0

Exhaust products of any internal combustion engine are

if

toxic and can cause injury, or death applications, especially those within

inhaled.

All

a

confined area,

engine

should be equipped with an exhaust system to discharge gases

to

the outside atmosphere.

0

Do not use exhaust gases

0

Make sure that your exhaust system is free of leaks.

to

heat a compartment.

Ensure that exhaust manifolds are secure and are not warped by bolts unevenly torqued.

Exhaust Gas

is

Deadly!

Exhaust gases contain carbon monoxide, a poisonous gas that can cause unconsciousness and death. It is an odorless and colorless gas formed during combustion of hydrocarbon fuels. Symptoms of carbon monoxide poisoning are:

0

Dizziness

0

Headache

0

Weakness .and Sleepiness

If

you experience any of these symptoms, get out into fresh air

immediately, shut down the unit and do not use until

0

Vomiting

0

Muscular Twitching

0

Throbbing in Temples

it

has

been inspected. The best protection against carbon monoxide inhalation

proper installation and regular, frequent inspections

of

is

the complete exhaust system. If you notice a change in the sound or appearance of exhaust system, shut the unit down

immediately and have

it

inspected and repaired at once

by

a

competent mechanic.

b

'

0

Keep your hands away from moving parts.

Batteries

Before starting work on the engine, disconnect batteries to prevent inadvertent starting

DO NOT batteries give

SMOKE

off

a highly explosive hydrogen gas which

can be ignited by flame, electrical arcing or by smoking. Verify battery polarity before connecting battery cables.

Connect negative cable last

of

the engine.

while servicing batteries. Lead acid

Cooling

System

0

Coolants under pressure havea higher boiling point than

DO

water.

NOT open a radiator pressure cap when coolant temperature is above 212OF (lOO°C) or while engine

is

running.

Keep the

0

Unit

and Surrounding Area Clean

Make sure that oily rags are not lefl on or near the engine Remove all unnecessary grease and oil from the unit.

Accumulated grease and oil can cause overheating and subsequent engine damage and present a potential fire hazard.

a

E-6

Table

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by any means, is strictly prohibited.

of

Contents

TITLE PAGE

General Information Specifications

Dimensions and Clearances Assembly Torques and Special Tools Engine Troubleshooting

Oil

System Fuel System Ignition and Battery Charging Starting Engine Disassembly

Exhaust gases from all fuels (including diesel, gasoline, liquid prop ne, natural gas) contain carbon monoxide, an odorless and colorless gas. Carbon monoxide is poisonous and can cause unconsciousness and death. Symptoms of carbon monoxide poisoning can include:

..........................................................

........................................................

System

.................................................

......................................................

..........................................

.................................

.............................................

........................................

.....................................................

................................................

I

AWARNING

EXHAUST

GAS

1

IS

DEADLY!

1-1 2-1

3-1

4-1

5-1

6-1

7-1

8-1

9-1

10-1

0

Dizziness

0

Nausea Muscular Twitching

0

Headache

Weakness and Sleepiness

YOU

IF INTO atfention. Shut down the unit and repaired.

Protection against carbon monoxide inhalation includes proper installation, ventilation and regular, frequent visual and audible inspections

exhaust system.

OR ANYONE

THE

FRESH

Throbbing in Temples

0

Vomiting

0

Inabirity to Think Coherently

ELSE

EXPERIENCEANY OF THESE SYMPTOMS, GET

AIR

IMMEDIATELY. If symptoms persist, seek medical

do

not operate untilit has been inspected and

of

the complete

i

OUT

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by any means, is strictly prohibited.

General Information

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by any means, is strictly prohibited.

.

*

INTRODUCTION

This manual deals with specific mechanical and electrical information needed by engine mechanics for troubleshooting, servicing, repairing, or overhauling the engine.

Use the separate PARTS MANUALfor parts identification and for establishing their proper location on assemblies. The PARTS MANUAL contains detailed exploded views of each assembly and the individual piece part numbers

and their proper names for ordering replacement parts. The illustrations and procedures presented in each

section apply to the engines listed on the cover. The flywheel-blower end of the engine is the front end

right and left sides are determined by viewing the engine

1

from the front. The No. cylinder is on the right.

If

a major repair or an overhaul is necessary, acompetent mechanic should either do the job or supervise and check the work of the mechanic assigned to the job to ensure that all dimensions, clearances and torque values are within the specified tolerances.

Use the table of contents for a quick reference to the separate engine system sections.

The troubleshooting guide is provided as a quick reference for locating and correcting engine trouble.

The wiring diagram shows how the electrical components are interconnected.

The disassembly section contains major overhaul procedures for step by step removal, disassembly, inspection, repair, and assembly of the engine components.

cylinder is on the left, No.

so

2

to

Use only Genuine Onan replacement parts quality and the best possible repair and overhaul results. When ordering parts, always use the complete

model and spec number as well as the serial number

shown on the nameplate.

ENGINE

Identify your model specification (spec letter) as shown on the unit nameplate. Always use these numbers and the engine serial number when making reference

How to interpret

B

48

TTTTTT

123456

1.

Factory code for general identification engine series.

2.

Cubic inch displacement.

3.

Engine duty cycle.

4.

Fuel required (G=gasoline).

5.

Cooling system description

(A=air-cooling-pressure).

6.

BHP rating.

7.

Factory code for designated optional equipment, if any.

8.

Specification (spec letter) which advances with factory production modifications.

MODEL

by

MODEL

G G

REFERENCE

referring to the model and

to

your engine.

and SPEC

A

0201

NO.

1

D

TT

78

ensure

of

basic

INCORRECT SERVICE OR REPLACEMENT SEVERE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE PERSONNEL MUST BE QUALlFlED TO PERFORM ELECTRICAL AND/OR MECHANICAL SERVICE.

IAWARNING

1-1

i

OF

PARTS CAN RESULT IN

,

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by any means, is strictly prohibited.

a

Specifications

Redistribution or publication of this document, 

by any means, is strictly prohibited.

This manual contains

SPECIFICATION MEASURE B43E 8436

Number Bore in

Stroke in

Displacement

Compression Ratio Rated Speed (Maximum) RPM Power at BH P

Oil

Oil Filter Capacity Qts

Crankshaft Rotation

Valve Clearance (Cold)

Spark Plug Gap in

Breaker Point Gap - Static

of

Cylinders

Rated Speed (kW)

Capacity

Without Filter

(viewed from flywheel) Clockwise

Intake in

Exhaust in

(Full Separation and Engine Cold) in

SI

metric equivalents that follow immediately in parentheses

after the

U.S.

customary units

UNIT

OF

of

measure.

2

SERIES

2

3.250 3.250 3.250

(mm)

(82.55) (82.55) (82.55)

2.620 2.620 2.875

(mm)

cu

in

(cm3)

(66.55)

43.3 43.3 47.7

(71

6.2

0)

to

1

(71

6.5

0)

to

3600 3600 3600

16 18 20

(13.4) (1 4.9)

1.5 1.5

(1

-4)

Qts

(I

i

tre)

(1

1.9)

1.5

(1.4)

.3 .3 .3

(litre)

(mm)

(-3) (*3) (-3)

Clockwise Clockwise

.005

(-1

3)

.013

.005 (-1

3) (.13)

.013 .013

(.33) (.33) (.33)

.025 .025

(rnm)

(.64) (.64) (.64)

.016 .016

(mm)

in

(.41) (-41

)

1

B48G

2

(73.00)

(782)

7.0

to

1

(1

-4)

.005

.025

Spec

A

&

B

.020

(-53)

Begin Spec C

.016

Ignition Timing

Cylinder Compression psi

BTC BTC

(kPa)

2-1

Spec

16" 16" 20"

Begin Spec C

75

to

115 75

517

to

793 517

to

115 75

to

793 51 7

A

16"

to

115

to

793

&

B

,

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by any means, is strictly prohibited.

Dimensions

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by any means, is strictly prohibited.

and

Clearances

a

All clearances given at room temperature in parentheses) unless otherwise specified.

DESCRIPTION

CYLINDER BLOCK

Cylinder Bore Honed Diameter

Maximum Allowable

Taper

.........................................................

Out-of-Round Main Bearing Inside Diameter (Without bearing) Main Bearing Inside Diameter (Installed) Camshaft Bearing Bore (Bearing installed)

CRANKSHAFT Main Bearing Journal Diameter.. Main Bearing Clearance.. Connecting Rod Journal Diameter.. Crankshaft End Play..

CONNECTING Large Bore Diameter (Rod bolts properly torqued)

Connecting Rod Side Clearance..

Piston Pin Bushing Bore (Finished bore) Bearing to Crankshaft Clearance

Aluminum Rod

.................................................

...........................................

ROD

................................................

...................................

........................................

of

70°F.

(21

"C).

All dimensions in inches (approximate millimetre dimensions

...................

..........................

........................

.................................

..............................

.................

................................

..........................

.

MINIMUM

Inches

3.2490

2.187

2.0015

1.3760

1.9992

0.0025

1.6252

0.006

1.6280

0.0020

0.6879

0.0020

(mm)

(82.53)

(55.55)

(50.84) (34.95)

(50.78) (0.064) (41.28) (0.15)

(41.35) (0.051) (17.47)

(0.051)

MAXIMUM

Inches

3.2500

0.005

0.003

2.188

2.0040

1.3770

2.0000

0.0038

1.6260

0.01 2

1.6285

0.01 60

0.6882

0.0033

(mm)

(82.55) (0.1 3)

(0.08) (55.58) (50.90) (34.98)

(50.80) (0.097) (41.30) (0.30)

(41 -36) (0.406)

(1

7.48)

(0.084)

CAMSHAFT

Bearing Journal Diameter..

Bearing Clearance.. End Play. Camshaft Lift

B43G, B43E

PISTON Clearance in Cylinder

Measure Piston Pin Bore.. Ring Groove Width

Top 1 Compression Ring.. No. 2 Compression Ring.

No.

.......................................................

8486

.........................................................

90"

3

Oil Control Ring

.............................................

...................................................

to

1.187

................................................

-

.........................................

......................................

inch below top of piston

...............

.....................................

......................................

1.3740

0.0015

0.0030

0.0033

0.68774

0.080

0.188 i4.775j 0.189 i4.801

(34.90) (0.038) (0.076)

0.300

0.258

(0.084)

(1

7.47)

(2.032) (2.0321

1.3745

0.0030

(7.62) (6.55)

0.0053

0.68814

0.081

(34.91 (0.076

(0.135) (17.48)

(2.057)

12.057)

)

j

3-

1

DESCRIPTION

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by any means, is strictly prohibited.

MINIMUM MAXIMUM

Inches

(mm)

Inches

(mm)

PISTON PIN

Clearance in Piston Clearance in Connecting Rod

Aluminum Rod

Diameter

PISTON RINGS

Clearance

Top

Ring End Gap in Cylinder

INTAKE VALVE

Stem Diameter

Clearance (Stem to Guide)

Valve Face Angle

INTAKE VALVE SEAT

Seat Bore Diameter

Seat Outside Diameter Valve Seat Width Valve Seat Angle

EXHAUST VALVE

Stem Diameter

Clearance (Stem

Valve Face Angle

........................................................

Groove

..............................................

................................................

...................................................

........................................

..................................................

.......................................

................................................

.............................................

...........................................

................................................

..................................................

to

Guide)

.......................................

................................................

0.00004 (0.001

0.0002

0.6875 (17.46) 0.6877

0.003

0.010 (0.254) 0.020

0.3425 (8.70) 0.3430 (8.71)

0.0010

1.4395

1.443

0.031 (0.787)

0.3410 (8.661) 0.3415 (8.674)

0.0025 (0.064) 0.040 (0.102)

0)

0.00064 (0.01 62)

(0.005)

(0.076)

(0.025) 0.0025 (0.064)

(36.56) (36.65)

0.0007

0.008

44"

1.4405 (36.59)

1.444 (36.67)

0.047 (1.194)

45"

44"

(0.01 8) (17.47)

(0.203) (0.508)

c

EXHAUST VALVE SEAT

Seat Bore Diameter Seat Outside Diameter Valve Seat Width Valve Seat Angle

VALVE GUIDE

Inside Diameter

TAPPET

Body Diameter Bore Diameter Clearance in Bore

VALVE SPRINGS INTAKE AND EXHAUST

Valve Spring Free Length (Approx.) Valve Spring Length

Valve Open Valve Closed

Spring Load Spring Load @ 1.125 inch (Valve Open)

GEAR

Timing Gear Oil Pump Gear

GOVERNOR

Dashpot

@I

BACKLASH

.....................................................

to

Governor Arm Bracket

..............................................

...........................................

................................................

.................................................

..................................................

...................................................

...............................................

..............................

....................................................

..................................................

1.375 inch (Valve Closed)

..........................

...........................

..................................................

................................

)

Ib

5

. .

(30.23) (1.1 94)

(19.00) (1 9.09) (0.076)

(19 kg) (36 kg)

(0.152) (0.127)

1.1 89 (30.20) 1.190

1.192 (30.28) 1.193 (30.30)

0.031

0.344 (8.74) 0.346 (8.79)

0.7475 (18.99) 0.7480

0.7505 (1 9.06) 0.751

0.0015

38 71

0.001

0.002

0.040 (1.02) 0.060 (1.52)

(0.787) 0.047

(0.038) 0.003

1.662 (42.21

1.1

1.375 (34.93)

Ib

.

(17

Ib

.

(32

(0.025)

(0.051)

45O

25 (28.58)

kg)

42

79

0.006

0.005

3-2

Assembly

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by any means, is strictly prohibited.

Torques

1

.

The torque values given in Table 1 have been deter-

mined for the specific applications. Standard torque values must not be used where those listed in Table apply. The engine assembly torques given here will

of

assure proper tightness without danger

All

threads. new engine

threads must

oil

before torquing.

be

clean and lubricated with

stripping

TABLE

TORQUE

DESCRIPTION SPECIFICATION

Ft.-Lb. Nm

Gearcase Cover Cylinder Head Bolts (Cold)

Asbestos Gasket

Graphoil Gasket

Rear Bearing Plate Screws Starter Mounting Bolts Connecting Rod Bolt.. Flywheel Cap Screw.. Oil Base

......................

...............

............

.............

.....

.........

8-1

0

16-18 22-24 14-1 6 19-22 25-27 34-37

24-26 33-35

14 19

50-55

18-23 24-31

11-14

68-75

1

Check all studs, nuts, and capscrews, and tighten as required to keep them from working loose. Refer to the PARTS MANUAL for the location of washers and

capscrews.

1.

TORQUE

DESCRl PTl ON SPECIFICATION

FLLb. Nm

Intake Manifold Mounting

Screws.. Oil Pump Valve Cover. Exhaust Manifold Mounting

Screws Other 1 /4" Cylinder Block

Stud and Nuts.. Other 511

Stud and Nuts..

...................

.....................

..................

.....................

.............

6"

Cylinder Block

.............

6-10 8-1

7-9 10-1 2 1-2 1-3

6-10 8-1 4

7-9 10-1

8-10 11-14

4

2

Special

The following special Onan. For further information see

900-0079.

.

Valve Seat Driver Valve Guide Driver

Oil

Seal Guide and Driver Combination Bearing Remover (Main and Cam) Combination Bearing Driver (Main and Cam) Flywheel Puller

Tools

tools

are available from

TOOL

CATALOG

4-1

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by any means, is strictly prohibited.

Engine

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by any means, is strictly prohibited.

Troubleshooting

GASOLINE

TROU

BLES

HOOTlN

ENGINE

G

5-1

C

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Oil

Redistribution or publication of this document, 

by any means, is strictly prohibited.

System

1

Refer

to

Periodic Maintenance Schedule (located in the

I

Operator's Manual) for oil change interval. If operating in extremely dusty, high ambient, or conditions, change oil more often.

CRANKCASE

OIL

low

ambient

llEGE%l

Do

injury.

Oil level should be

not check oil while fhe engine

Crankcase pressure can blow out hot

oil,

which can cause severe personal

is

running.

to

the

FULL

mark of the dipstick. Start

engine and run for a short time to check for oil leaks

Hot crankcase oil can cause burns if it

comes in contact with skin. Wear

around the drain plug.

protective clothing and keep fingers and hands clear

when draining oil.

(BCAUTION]

Excess oil can cause high oil consumption, high operating temper-

atures, and oil foaming.

Do

not overfill crankcase.

Run engine until thoroughly warm before draining oil. Stop the engine, place a pan under the drain outlet and remove the oil drain plug. After the oil is completely drained, clean and replace thedrain plug. Fill crankcase with correct amount crankcase capacity. Use oils meeting the fication

SF,

SF/CC,

of

oil. Refer to SP€C/NCAT/ONSfor

API

or

SF/CD.

Refer to chart

to

determine

classi-

the proper viscosity grade of oil to use. Straight weight

oils

are recommended for severe duty use and at

32OF

(OOC)

temperatures above

for minimum oil

consumption.

F

-20

c30

TEMPERATURE RANGE

-lo

0

-io

20

YOU

40

b

EXPECT

60

10

i0

BEFORE NEXT

80

3b

OIL

100

40

CHANGE

LS-1170

CAUTION

1

ADD ONE PINT

FIGURE

1.

CRANKCASE

ALWAYS REPLACE

TIGHTLY

LEAKAGE MAY OCCUR

-

DO

OR

OIL

NOT OVERFILL

(0.5

litre)

OIL

FILL

c-1000

6-1

I

COOLING FINS

FIGURE

2.

OIL

c-1001

FILTER

OIL FILTER CHANGE

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Refer to Periodic Maintenance Schedule, located in the

oil

Operator’s Manual, for operating in extremely dusty, high ambient, or low ambient conditions change oil more often.

off

Spin clean filter mounting surface and install new element, making sure new gasket is inserted in the element. Apply a thin film of by hand until gasket just touches mounting pad and then turn down an additional overtighten.

With oil in crankcase, start engine and check for leaks around filter element. Retighten only as much as necessary to eliminate leaks; do not overtighten.

oil filter element and discard

oil

to the gasket. Spin element down

filter change interval.

it.

Thoroughly

1/2-3/4

turn.

Do

If

not

CRANKCASEBREATHER

Refer to Periodic Maintenance Schedule, located in the Operator’s Manual, for crankcase breather service

if

interval. Service sooner surized as evidenced by oil leaks at the seals or excessive oil in the air cleaner housing.

crankcase becomes pres-

.

Most parts cleaning solvents are

flammable and can cause severe personal injury manufacturer’s recommendations when cleaning parts.

Remove the breather tube from the valve cover (Figure

3).

Remove the pack, capscrew, flatwasher, valve cover and gasket, spring, flatwasher, reed valve, and breather baffle. Discard gasket and clean all parts in parts cleaning solvent.

ACAUTlON

=

tighten

The reed valve must be flat with no sign of a crease. Assemble using a new gasket. Torque capscrew to

ft-lbs

valve cover.

(1

-3

Nm).

or

death if used improperly. Follow the

Overtightening the valve cover can cause engine damage.

Do

not over-

1-2

FIGURE

3.

CRANKCASE BREATHER

c-low

6-2

.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

PRESSURE

All

engines ofoil to theengine parts.Theoil supply collect sin the oil base where

cup.

Drain oil before removing oil base and always use a

new gasket when replacing the oil base.

Oil

Pump

The oil pump (Figure 4) is mounted behind the gear cover and is driven by the crankshaft gear. Inlet pipe and screen assembly are attached directly to the

pump body.

registers with a drilled passage in the crankcase. Parallel passages distribute oil to the front main bearing, rear main bearing, and pressure control bypass valve.

use

an

it

is picked up by the oil pump pick-up

A

by-pass valve is

A

discharge passage in pump cover

LUBRICATION

oil

pump

to

used

to control

OIL

PUMP

provide a constant

oil

pressure.

PICK-UP

CUP

flow

Oil

Check oil pump thoroughly for worn parts. to prime it before reinstalling. Exceptfor gaskets and

of

pick-up cup, component parts available individually. Install a new pump assembly any parts are worn.

Oil

By-Pass

The by-pass valve (located to the right and behind

gear cover), controls oil pressure by allowing excess oil to flow directly back to the crankcase. Normally the valve begins to open about

The valve is non-adjustable and normally does not

need maintenance. Determine if valve is operating normally by inspecting plunger action as follows:

1. Remove the 3/8 x behind gear cover and under governor arm.

2. Remove spring and plunger with a magnet tool.

3. Determine proper valve operation by checking the spring and plunger according to the following measurements.

Valve

24

x 7/8 cap screw located

the pump are not

20

psi (138 kPa).

pump

if

*

.

OIL

PUMP

ASSEMBLY

CRANKCASE

ON

FIGURE

Circumferential grooves in the main bearings supply oil to connecting rod bearings through drilled passages from each main journal. connects the front main bearing oil supply to the front camshaft bearing; rear cam bearing is splash lubricated. Oil overflow from the bypass valve furnishings lubrication to the camshaft drive gears.

Normal oil pressure should be 30 psi higher when the engine is at normal operating temperature. If pressure drops below this value at

governed speed, inspect oil system for faulty

components.

4.

LEFT

OIL

TURNED

SIDE

PUMP

ASSEMBLY

A

drilled passage

(207

Ls-iiog

kPa) or

Plunger Diameter.,

Spring

Free Length..

............

Load

when compressed to

4.

Check the valve seat and clean away any accumulation of metal particles which could cause erratic valve action. Verify that the valve seat is not damaged.

5.

Clean plunger and spring in parts cleaning solvent and install.

........

...........

2.6 f 0.2

0.3105 to 0.3125 in. (7.89 to 7.94 mm)

1.00

inch (25.4 mm)

Ibs

(11.6 & 0.9 N)

0.5

inch (12.7 mm)

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Fuel

Redistribution or publication of this document, 

by any means, is strictly prohibited.

System

,

CARBURETOR

Nikki

full

adjustment carburetor mixture screw

settings:

Most carburetors have a fixed main jet. An optional main fuel adjustment kit (altitude compensation kit) is available.

The carburetor idle mixture was set for maximum efficiency at the factory and should normally not be disturbed. the ignition system is working properly and governor sensitivity is properly adjusted.

If

adjustment is needed, refer to Figures 1 and 2 and

proceed as follows:

I]

Turn

If

adjustments seem necessary, first be sure

Overfightening the mixfure adjustment screw

will

cause carburetor damage.

mixture adjustment screw

in

on/y

until

light

tension can be felt.

1.

Walbro carburetor mixture screw settings:

Turn both mixture screws in until lightly seated, then

/8

back the idle mixture screw out 1-1 main mixture screw out 1-1

/2

turns and the

turns.

Turn idle mixture screw in until lightly seated, then back idle mixture screw out 1-1 equipped with optional main fuel adjustment, turn main mixture screw in until lightly seated then back the main mixture screw

B43E B43G B48G

1-1 1

out

718

to

14

to 1-1

-5/8

to 1-718 turns

/4

turn. On engines

as specified below.

1-1

/8

turns

/2

turns

Nikki limited idle adjustment carburetor mixture

screw settings:

The carburetor has a limited idle adjustment range

between stops of *1/8 turn. The screw should only be adjusted within these limits; in to lean the mixture, out to richen. There is no main mixture

adjustment. When replacing the idle mixture screw, turn until

lightly seated, then turn back idle mixture screw out

/4

turn. Replace the limiter cap with the plastic

1-1

stop approximately centered.

SIDE PULL GOVERNOR ASSEMBLY

FIGURE

1.

GOVERNOR SPEED ADJUSTMENT

LOW

__--

FRONT PULL GOVERNOR ASSEMBLY

SPEED

7-1

2.

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by any means, is strictly prohibited.

Start the engine and allow

roughly (at least

10

minutes).

it

to warm up tho-

Some equipment manufacturers may require

higher throttle stop speed and governor low speed rpm settings. Referto equipment manufacturer’s Operators Manual for the correct rpm set-

tings. When rpm settings are not specified by the equipment manufacturer, use the rpm settings

3

&

listed in Steps

5.

\

3.

Move the engine speed control to the slow position. Bend or turn the low speed stop on the governor

so

that the throttle stop screw on the car-

buretor controls enginespeed. Adjust the throttle

1000

stop screw for

4.

Determine the best idle mixture setting by first

rpm idle.

turning the idle adjustment screw in until engine

speed drops and then outward until engine speed drops again. Over a narrow range between these

two settings, engine speed remains at its highest.

Set the adjustment screw about (rich) from the midpoint

1

/8

of

this range. On Nikki

turn outward

limited adjustment idle mixture carburetor adjustments are limited to

turn. Do not

go

beyond

fl/8

these limits.

5.

Readjust the throttlestop screw for

1000

rpm idle,

then adjust the governor low speed stop for

rpm idle.

1100

THROTTLE

SZEw

\

IDLE FUEL

ADJUSTMENT

WALBRO CARBURETOR

NlKKl CARBURETOR

FS-1002

LOCATION

OPTIONAL MAIN

FUEL ADJUSTMENT

OF

FS-1406

.

6.

Move the engine speed control

tion. Bend the high speed stop on the governor the engine runs at the equipment manufacturer’s

recommended speed.

7.

Checkthe main mixtureadjustment (if by rapidly accelerating the engine from idle to full

speed. The engine should accelerate evenly and without hesitation.

adjustment screw out in the engine accelerates smoothly, but do not turn

out more than

1

/2

to

the fast posi-

so

equipped)

If

it

does not. turn the main

1

/8

turn increments until

it

turn beyond the original setting.

7-2

NlKKl CARBURETOR WITH SEMI-AUTOMATIC CHOKE AND LIMITED IDLE

FIGURE

MIXTURE

2.

CARBURETOR

SCREW.

ADJUSTMENTS

FS-1406-2

CARBURETOR OVERHAUL

Redistribution or publication of this document, 

by any means, is strictly prohibited.

CHOKE PLATE

Carburetion problems that are not corrected

by

mixture adjustments are usually a result of gummed-

up fuel passages or worn internal parts. The most

effective solution is a complete carburetor overhaul.

In general, overhauling a carburetor consists

of

complete disassembly, a thorough cleaning, and

of

replacement

worn parts. Carburetor repair parts

are available.

General instructions for overhauling a carburetor are given below. Carefully note the position of all parts while removing to assure correct placement when reassembling. Read through all the instructions before

beginning for a better understanding of the pro-

cedures involved. Carburetor components are shown

in Figure

3.

/snition of fuel can resulf in severe

-1

personal injury or death.

Do

not smoke or allow any spark, pilot light, or arcing equipment near the fuel system.

D

t

THROTTLE STOP

SCREW

IDLE ADJUSTME

-*

CHOKE SHAFT

HROTTLE PLATE

WALBRO CARBURETOR

CHOKEPLATE

..

NlKKl CARBURETOR WITH SEMI-AUTOMATIC CHOKE

AND

LIMITED IDLE MIXTURE SCREW.

FLOAT

CAP

'

ASSEMBLY

FIGURE

a

FS-1440-3

3.

CARBURETOR ASSEMBLY

-9

/-

!

'THROTTLE PLATE

b

FLOAT ASSEMBLY

FIXED

NlKKl CARBURETOR

CHOKE SHAFT

OPTIONAL MAIN

FUEL ADJUSTMENT

\

IDLE ADJUSTMENT IDLE ADJUSTMENT

FS-1440

7-3

Removal

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by any means, is strictly prohibited.

1.

Remove air cleaner and hose.

2.

Disconnect governor and throttle linkage, choke

control and fuel line from carburetor.

3.

Remove the four intake manifold cap screwsand lift

complete manifold assembly from engine.

4.

Remove carburetor from intake manifold.

Disassembly (Walbro and Nikki)

1.

Remove throttle and choke plate retaining screws,

Pull

then plates.

2.

Remove main jet and idle adjustment needle. Remove attaching screws and separate upper and

3.

out throttle and choke shafts.

lower carburetor sections.

4.

Carefully note position of float assembly parts, then pull out retaining pin and float assembly.

5.

Remove needle and unscrew needle valve seat.

Disassembly (Nikki limited idle mixture)

1.

Remove main jet and idle adjustment needle.

2.

Remove attaching screws and separate upper and lower carburetor sections.

3.

Carefully note position of float assembly parts, then pull out retaining pin and float assembly.

4.

Remove needle valve.

Reassembly and Installation (Walbro and Nikki)

1.

Install needle valve and seat, main jet and float assembly. Make sure that float pivot pin is properly placed and that the float moves freely without binding.

2.

Gently push float tang down until needle measure float level as shown in Figure

just

4.

seats;

Adjust

float level if necessary. Release float tang and

4

measure float drop as shown in Figure

(the

distance from top of carburetor body to top of float).

3.

Position gasket on lower carburetor section and install upper carburetor section.

4.

Slide in throttle shaft and install plate using new screws. Before tightening the screws, the plate must

To

do

so,

back

off

be centered in the bore.

the throttle stop screw as necessary and completely close the throttle lever. Seat the plate by tapping with a small screwdriver, then tighten screws. Install the choke shaft and plate in the same manner.

5.

Install idle adjustment screw, throttle stop screw, and fixed main jet plug or optional main fuel adjustment needle.

6.

Mount carburetor on intake manifold and install assembly on engine.

7.

Mount air cleaner assembly. Connect air intake hose, breather hose, fuel line, vacuum line, and throttle linkage.

8.

Adjust carburetor and governor according to directions given in this section.

,I

Cleaning and Repair

1.

Soak all metal components not replaced in carburetor cleaner. Do not soak non-metal floats or other non-metal parts. Follow the cleaning manufacturer’s recommendations.

2.

Clean all carbon from the carburetor bore, especially where the throttle and choke plates seat. Be careful not

to

plug the idle or main fuel ports.

3.

Dry out all passages with low pressure air

Avoid using wire or other objects for cleaning that

may increase the size of critical passages.

4.

Check the condition of adjustment needle. Replace if damaged. Replace float

damaged.

5.

Check the choke and throttle shafts for excessive play in their bore. This condition may necessitate replacement of the carburetor.

6.

Replace

old

components with new parts.

(35

if

loaded with fuel or

PSI).

Reassembly and Installation (Nikki limited idle mixture)

1.

Install needle valve, main jet, and float assembly.

Make sure float pivot pin is properly placed and float

moves freely without binding.

2.

Turn carburetor on its side and measure float level

4).

(Figure

Adjust float level only if necessary. Measure float drop (the distance from the top of carburetor body to top of float). Adjust only if necessary.

3.

Position gasket on lower carburetor section and install upper carburetor section.

4.

Install idle adjustment screw, throttle stop screw, and fixed main jet plug.

5.

Mount carburetor on intake manifold and install assembly on engine.

6.

Mount air cleaner assembly. Connect air intake hose, breather hose, fuel line, vacuum line, and throttle linkage.

7.

Adjust carburetor and governor according to directions given in this section.

7-4

1

BEND

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FLOAT

TAB HERE

TO ADJUST

AND SEAT

0.02kO.02

FLOAT LEVEL ADJUSTMENT WITH FUEL NO FUEL

INCH

FUEL LEVEL

0.25

INCH

I

RBURETOR

When checklng float

level

and float drop measure to float body, not seam.

MINIMUM HERETO ADJUST

FLOAT

DROP

I

0.20lNCH

FLOAT DROP ADJUSTMENTS

BEND FLOAT ARM

/

WALBRO FLOAT LEVEL ADJUSTMENT

FS-1524

BEND FLOAT

TANG HERE

TO

ADJUST

NE~DLE

AND SEAT

NEEDLE

AND SEAT

0.028"k0.028"

(0.712k0.712

FLOAT LEVEL ADJUSTMENT WITH FUEL

rnrn)

When

checking float

~

0.394"

FUEL LEVEL

(10.0

mm)

level

and float drop measure

NiKKl FLOAT LEVEL ADJUSTMENT

BEND FLOAT

~N~~~~~

to

float body, not seam.

MINIMUM

DROP

FLOAT

0.213"

(5.41

mm)

BEND FLOAT ARM

HERE TO ADJUST

NO

FUEL

FLOAT DROP ADJUSTMENTS

BEND FLOAT ARM

MINIMUM

HERE TO ADJUST

FS-1689

u

V

FLOAT LEVEL ADJUSTMENT

WITH

FUEL NO FUEL

When checking lloat

NlKKl FLOAT LEVEL ADJUSTMENT CHOKE AND LIMITED IDLE MIXTURE SCREW.

FIGURE

4.

level

and float drop measure to float body, not seam.

WITH

CARBURETOR FLOAT LEVEL ADJUSTMENTS

7-5

SEMI-AUTOMATIC

I

FLOAT DROP ADJUSTMENTS

I

FS-1683

PULSATING-DIAPHRAGM FUEL PUMP

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Pulsating diaphragm fuel pumps, or pulse pumps, rely

on changes in crankcase vacuum to create a pulsating

As

movement of the pump diaphragm. pistons move outward, a vacuum is created. This vacuum is transmitted to the pump diaphragm, causing

to

pull back and suck fuel into the pump.

it engine’s pistons move inward, crankcase vacuum is reduced and the diaphragm return spring pushes the pump diaphragm forward, forcing fuel through the pump outlet.

Fuel Pump

Before testing make certain that fuel pump vacuum line connections are tight and free of leaks.

1.

Operate engine at an idle for five minutes to ensure

that carburetor is full of fuel.

2.

Shut engine Pump.

71

Test

Procedure

off

and remove fuel inlet line from fuel

Ignition of fuel can result in severe personal injury or death.

Thoroughly clean up any spilled fuei

3.

Connect a vacuum gauge tofuel pump inlet using a piece of fuel hose with clamps.

4.

Start engine and allow to idle for five seconds. Record vacuum gauge reading.

the engine’s

As

the

11.

Shut engine from fuel pump outlet. Connect fuel outlet line to fuel

pump.

Repair or replace the fuel pump

within the values specified

off

and remove pressure gauge hose

if

test readings are not

in

TABLE

1.

1

PULSE PUMP TEST SPECIFICATIONS

Engine

Speed

Low

High

Idle

Pump

Inlet

Vacuum

(Minimum) (Minimum)

2.6

inches

of

mercury

2.6

inches

of

mercury

Pump

Pressure

1.7

Outlet

psi

Fuel Pump Repair

This section applies only to Facet fuel pump. The Nikki fuel pump is not repairable; replace unit are not within the values specified in Table

1.

Remove thevacuum and fuel lines. Inspect the lines for wear, cracking or brittleness. Replace as necessary.

2.

To insure correct alignment when reassembling, scribe a line across the outer pump parts on each end of the pump.

if

test readings

1.

I

5.

Move throttle control to high idle position. Wait five

seconds and record vacuum gauge reading.

Shut engine

6.

from fuel pump inlet. Connect fuel inlet line to fuel

pump.

7.

Remove fuel outlet line from fuel pump.

-1

off

and remove vacuum gauge hose

Ignition

of

fuel can result in

severe personal iniurv or death.

Thoroughly clean up any spilled fuei

8.

Connect a pressure gauge tofuel pump outlet using

a piece of fuel hose with clamps.

9.

Start engineand allow to idle for five seconds. While holding pressure gauge level with pump outlet record pressure gauge reading.

10.

Move throttle control to high idle position and allow engine to run for five seconds. While holding pressure gauge level with pump outlet record pressure gauge reading.

3.

Holding the pump carefully, remove the assembly screws (Figure

4.

Carefully pull apart the pump sections and check for

or

worn

5.

Check and unclog

air bleed hole located behind the pump diaphragm

in the pump base.

damaged parts. Install pump repair kit.

ACAUTION

5.)

if

necessary the small diaphragm

A

clogged diaphragm air bleed

hole can cause diaphragm wear and seal damage. Be sure air bleed hole unclogged.

6.

Replace gaskets and reassemble pump. Reinstall

assembly screws, checking the scribe marks for

proper alignment. Reinstall fuel and vacuum lines

and clamps.

[-I

Improper fuel pump

or

ment

misconnected fuel lines

parts

can result in leaking fuel, creafing a serious fire

hazard. Use extreme care when reassembling and reinstalling fuel pump.

is

1

align-

7-6

PUMP

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by any means, is strictly prohibited.

COVER

\

GASKET

\

I

ASSEMBLY SCREWS

AIR

(BCAUTIONI

A

dirty air cleaner element can cause

FIGURE

CLEANER

REED

VALVE

5.

EXPLODED VIEW OF FACET FUEL

engine damage. Ensure air cleaner

is

element

kept clean and free

Engine is equipped with

a

of

excess debris.

paper element.

If

the engine is

equipped with polyurethane precleaner, it must be

removed, cleaned and oiled every

25

hours

of

operation,

or more under extremely dusty conditions.

1.

To

clean precleaner wash in water and detergent, refer to Figure like a sponge, and allow

6.

Remove excess water by squeezing

to

dry thoroughly.

PUMP

Distribute one tablespoon

of

SAE

FS-1684

30

engine oil evenly around the precleaner. Knead into precleaner and wring out excess oil.

2.

Depending on conditions in which the engine is operating, the inner paper element should be replaced whenever it becomes excessively dirty or oily.

ACAUT~ON

D

engine damage.

Running engine without air cleaner element wi// result in

Do

not run engine without air

cleaner element installed.

L

*

WRAPPER

FIGURE

FS-1131

6.

AIR CLEANER ASSEMBLY

7-7

1.

WASH

2.

SQUEEZE

3.

COAT WITH

4.

INSTALL OVER PAPER ELE

DRY

OIL

DASHPOT

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by any means, is strictly prohibited.

GOVERNOR

ARM BRACKET

0.050

INCH

(1.27

mm)

STOP

FIGURE

DASHPOT ADJUSTMENT

1.

Pull governor arm and linkage (away from carburetor) until throttle stop contacts throttle stop screw.

2.

Holding throttle against throttle stop screw, adjust dashpot to obtain (Figure

3.

Secure dashpot to air cleaner support bracket with hex nut provided.

ACAUT~ON

a

when securing dashpot.

7.)

0.050

inch

Dashpot

held

with

(1.27

mm) clearance

damage can occur

pliers.

Do

not use

7.

DASHPOT

if

p/iers

CLEARANCE

GOVERNOR SENSITIVITY

These engines are adapted for use where a wide range

of

speed settings is desired (Figure controlled at any given point between minimum and maximum by simply shifting the throttle lever on the dash panel until the desired speed is reached.

The fixed and variable speed governor give an automatic decrease in sensitivity when the speed is increased. The

good

result is

A

reliable instrument for checking engine speed is required speed can be checked with a tachometer.

stability at

for

accurate governor adjustment. Engine

all

speeds.

8).

Engine speed

is

7

-8

.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

I

Check the governor arm, linkage, throttle shaft, and

lever

for

wear

binding

at

connecting points.

condition

A

or

excessive

binding

slack and

condition

at any

point will cause the governor to act slowly and regulation will be poor. Excessive looseness may cause a

hunting condition and regulation could be erratic. Work the arm back and forth several times by hand while the engine is idling to check for above con-

ditions.

If

the governor is hunting or not operating properly,

adjust as

1.

2.

follows

Disconnect linkage (A) from one of holes Push linkage

(toward carburetor) as they will

(Figure

8).

(A)

and governor arm

(B)

go.

(C).

as far back

3.

Holding linkage and governor arm toward direction

of

carburetor, insert end

ever

hole

(C)

in

governorarm

of

linkage into which-

lines

up

the

closest.

If between two holes, insert in next hole out.

On side pull governors the governor spring is set by

the factory

in

the third hole

of

the governor arm.

(Third hole from pivot). On front pull governors the

is

governor spring hole

of

the governor arm adapter. (Second hole from

To

pivot.)

increase sensitivity, move spring loop into

set by the factory in the second

a hole closer to the pivot. To decrease sensitivity,

move spring loop into a hole farther away from the pivot. After sensitivity has been set, recheck the low

speed rpm setting. Adjust if necessary.

THROTTLE

@

GOVERNOR

GOVERNOR SPRING GOVERNOR

s1

SIDE

SCREW

PULL

STOP)

CONTROL

GOVERNOR

SHAFT

.

YOKE

@

GOVERNOR

THROTTLE

SCREW

THROTTLE

LINKAGE

STOq

PLATE

CONTROL

GOVEkNOR

FRONT

SPRING

PULL

GOVERNOR

FIGURE

8.

VARIABLE SPEED GOVERNOR ADJUSTMENTS

7-9

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by any means, is strictly prohibited.

Ignition

Redistribution or publication of this document, 

by any means, is strictly prohibited.

I

G

N

IT1

0

I

The engine is equipped with an automotive type battery ignition system. Both spark plugs fire simultaneously,

thus

the need for a distributor

Thetiming is preset at thefactory. Slight timing changes can be made by adjusting the point gap.

The timing is adjusted engine assembly and is fixed by the point gap adjust-

To

ment.

the breaker points as recommended in the Periodic

Maintenance Schedule.

Replacement and Adjustment

1.

2.

3.

maintain maximum engine efficiency, change

Remove spark plugs. Remove breaker box cover. Rotatecrankshaftclock-

wise (facing flywheel) until points are fully open.

Remove condenser (screw A) and detach condenser lead and coil lead (screw densers mounted on the air cleaner bracket need

to

N

IGNITION

BREAKER

be removed unless being replaced.

and

Battery

SYSTEM D ESCRl PTI

is

eliminated.

TIMING

POINTS

to

specification during initial

6).

Engines with con-

ON

do

not

Charging

7.

Replace breaker box cover, coil wire, spark plugs, and spark plug cables.

Timing Test

As a check for proper ignition timing a continuity test

may be performed:

1.

Adjust breaker points.

2.

Remove blower housing

of

gearcase cover and flywheel (Figure

top

to

expose timing marks on

2).

YWHEELTIMING

(TC)

MARK

4.

Remove two Allen screws (C) and lift breaker assembly from engine.

5.

Replace condenser and point assembly with new parts and reinstall using above procedure in reverse order of removal.

6.

Adjust point gap by rotating crankshaft clockwise (facing flywheel) by hand until the points are fully open. Set the point gap (using flat feeler gauge) gap specified in

Allen screw (D) inward or outward (Figure

point gap is equivalent to 16" BTC.A.020 inch point

gap is equivalent to 20" BTC. Make sure feeler

is

gauge

clean and free

Sf€ClFlCATlONS

POINTGAP

W

FIGURE

1.

SETTING

by adjusting the

1).

of

any grease, oil, or dirt.

,.

POINT

GAP

to

A.016

M-1397

FIGURE

3.

Rotate flywheel clockwise until timing mark

aligned with the proper number of timing degrees

2)

(Figure

Refer to

timing degrees.

4.

Connect an ohmmeter or a continuity test lamp set across the ignition breaker points. Touch one test

prod to the coil lead terminal (screw

5.

Touch the other test prod to a good ground on the engine.

6.

Turn crankshaft against rotation (counterclockwise)

until the points close. Then slowly turn the crankshaft

with rotation (clockwise).

7.

The lamp should go out or continuity lost just as the points break which is where ignition occurs. timing is early (advanced) the point gap is

If

timing is late (retarded) the point gap is

Adjust point gap accordingly.

stamped on the top of gearcase cover.

SPEClFlCATlONS

2.

TIMING

MARKS

for proper number

B,

Figure

too

large.

too

small.

is

of

1).

if

IGNITION

Redistribution or publication of this document, 

by any means, is strictly prohibited.

To

test primary and secondary windings within the

COIL

ignition coil proceed as follows:

260

Use a Simpson

VOM or equivalent

Place black lead on ground (-)terminal of coil and red lead to positive (+)terminal. Primary resistance

should read 3.87

-

4.73

ohms.

BATTERY INSPECTION

Check battery cells with a hydrometer. The specific gravity reading should be approximately 1.260 at 77OF (25"C), Figure

If one or more cells are low on water, add distilled water and recharge. Keep the battery case clean and dry. An accumulation discharge and battery failure.

5.

of

moisture will lead to a more rapid

Change resistance setting on ohmmeter. Place ohmmeter leads inside of spark plug cable holes (Figure

-

3).

Secondary resistanceshould read 12,600

15,400 ohms.

If any of the above conditions are not met, replace coil. Refer to

PARTS CATALOG

for correct part

number.

c

OHMMETER

1

Keep the battery terminals clean and tight. Push the cable terminal down flush with or slightly below the top of the battery post (Figure 6).After making connections, coat the terminals with a light application of petroleum

jelly or grease to retard corrosion.

is

Poor contact at the battery cable connections

often a source of trouble. Make sure battery cables are in good condition and that contacting surfaces are clean and

tightly connected.

Do

not reverse battery leads. Use

recommended battery tools when disconnecting leads

to avoid mechanical battery damage.

Do

not

smoke

/Snition

can

or allow any ignition

of

result

explosive battery gases

in

severe personal injury.

source

near the

battery.

GRAVITY READING

SHOULD

1.260

BE

at

77'F

(25OC)

FIGURE

SPARK

Check, and regap spark plugs as recommended in the

Periodic

Manual). Replace spark plugs that show signs of fouling

or electrode erosion.

Maintenance

FIGURE

3.

COILTEST

PLUGS

Schedule

4.

SPARK

(located in Operator's

PLUG GAP

8-2

FIGURE

5.

SPECIFIC GRAVITY

BATTERY POST

f

6.

BATTERY CABLE CONNECTION

CABLETERMINAL

TEST

BATTERY

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Occasionally,

a

weak battery using a charged booster battery

your engine.

1

procedure damage, battery damage and personal injuries.

it

may

If

jump starting is necessary, the following

is

recommended in order to prevent starter

JUMP

be

necessary

STARTING

to

jump

start (charge)

to

start

AWARN~NG

a

explode,

death. near the battery, and battery.

resulting

Do

not smoke or allow

Jump starting a battery incorrectly can cause battery to

in

severe personal injury

any

ignition source

do

not jump start a frozen

or

-1

L

starter to cool

1

I

Disconnect engine load,

2.

Use only a battery of the same voltage used with your engine.

3.

Attach one end of the positive booster cable(red) to

the positive

Attach the other end positive

Attach one end of the negative

(black) to negative Attach other end ground on your engine.

-1

and negative cable ends to touch.

Jump starting in any other manner may result in damage to the battery or the electrical system.

Turn ignition switch to

Overcranking the engine can cause

starter damage. Allow

if

engaged for longer than

(+)

terminal of the booster battery.

of

the positive cable to the

(+)

terminal of your engine battery.

(-)

terminal of booster battery.

of

negative cable to a solid chassis

Electrical arcing can cause personalinjury.

ON

to start engine.

5

minutes for

30

(-)

booster cable

Do

not allowpositive

seconds.

(12V)

as is

This unit is equipped with a permanent magnet flywheel alternator and solid-state voltage regualtor-rectifier (output control). See Figure electrical units, precautions are necessary when servicing. Observe the following:

ACAUT~ON

I

to run without being connected to the alternator will result switch battery connections or allow engine to run

without being connected

Weak ignition spark or a discharged battery indicates

trouble in the charging system. But before testing the

engine's charging system, always check the battery for serviceability.

Keep these points in mind when testing or servicing the

flywheel alternator:

1.

enough to recharge batteryafter each start. Charging system tests require afull charged battery. Alternator

output is reduced in direct proportion to engine rpm.

Also,

available to recharge battery.

FLYWHEEL

Reversing positive and negative battery connections or allowing engine

in

engine electrical system damage.

Be sure engine is being run long enough and fast

power required for accessories reduces power

ALTERNATOR

7.

As

with all solid-state

to

the alternator.

Do

not

TO BATTERY

8-3

2.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

The regulator-rectifier has built in protection against open circuits or short circuits on the alternator output (B+) terminal. Either condition will cause the

off

regulator-rectifier toshut functioning. Prior to checking theregulator-rectifier, check all wiring between the regulator-rectifier terminal and the battery positive assure it is free of open circuits, resistances or short

circuits. Also, if the battery is extremely discharged it may have insufficient power to “turn on” the regulator-rectifier.

3.

Be sure regulator-rectifier plug (connector) is inserted properly. Plug must bottom in receptacle;

this eliminates any resistance due to a poor

connection. Keep clean and tight.

4.

Make sure alternator stator leads are not shorted

together.

5.

Be sure regulator-rectifier has a good ground connection. Mating surface for mounting must be clean and fastener tightened properly.

6. Never reverse the battery leads.

and appear as

(+)

terminal to

if

it is not

B+

ALTERNATOR

Use a volt-ohmmeter, such as the Simpson testing the charging system.

1.

With the engine running, check the battery terminal voltage (regulator output) using a DC voltmeter. Voltage output should be within the values specified

1.

in Table replace regulator-rectifier assembly. less than specified, proceed to step 2.

2.

Examineall wiresfor loose, corroded, broken connections, short circuits, etc. Check fuses. Repair as needed to assure complete circuits from regulatorrectifier B+ terminal

and from battery negative

rectifier case. engine running, proceed to step 3.

3.

Disconnect plug from regulator-rectifier and test

the AC voltage at the plug with engine running near

3600 rpm. specified in Table is as specified but DC voltage is low, replace regulator-rectifier.

If voltage is greater than specified

If

AC voltage reads more or less than

OUTPUT

to

battery positive

(-)

battery voltage remains low with

1,

proceed to step

TEST

270,

If

voltage is

(+)

terminal to regulator-

4.

If

AC voltage

when

I

*

terminal

With the engine between panel ammeter (if not already equipped, connect a test ammeter).

Alternator Output Test.

If

no charging is evident, proceed with the

1800

to 2600 rpm, observe the

TABLE

1.

TESTING

15- AND

I

BASIC

1. Battery

2.

Regulator

3.

Alternator Stator and Wiring

TEST

Battery Voltage - unit not running. Battery Voltage after unit is running

3

to 5 minutes.

Ohmmeter reading from stator

.

output

Check at plug.

-

PROCEDURE

unit not running.

4.

Use the opens in the stator (unit not running). Disconnect plug from regulator-rectifier. Connect ohmmeter

test leads to wires coming from stator. Refer to

Table not as specified, replace stator. readings are as specified and windings are not shorted to ground, low AC voltage may be due to

loss

must be replaced. Check for magnetism with steel tool blade. Next, connect one ohmmeter test lead to stator wire, connect the other test lead to ground. the ohmmeter reading is low the stator is grounded and must be replaced.

Rxl

scale on the ohmmeter for detecting

1

for resistance specifications.

of magnetism.

If

so,

blower wheel assembly

If

resistance is

If

stator resistance

PO-AMPERE SYSTEMS

I

15A.

13.6 to

0.1

SYSTEM

12

VDC

14.7

to

0.2

TEST

VDC

Ohms

rLUES

‘

13.6

20A.

0.3

SYSTEM

12VDC

to

14.7

to

0.5

VDC

Ohms

If

.

(4.

Alternator and Wiring

AC

open

Measure

voltage with unit running. Measure

between two stator leads with plug disconnected and unit running at approximately

circuit stator

3600

rprn.

8-4

I

40

VAC Minimum

60 VAC Maximum

31 VAC Minimum

51

VAC Maximum

O

Redistribution or publication of this document, 

by any means, is strictly prohibited.

ENGINE WIRING DIAGRAM

(Inertia

Type

Starter)

>u

*

2

'>

8.5

ENGINE WIRING DIAGRAM

Redistribution or publication of this document, 

by any means, is strictly prohibited.

(Solenoid

Shift

Type

Starter)

W

a

U

w

f

w

J

2

i

w

I

-.

pp

>n

“1

f

8-6

&+

W-

Starting

Redistribution or publication of this document, 

by any means, is strictly prohibited.

System

ELECTRIC STARTER

Normally the starter than possible brush replacement. However, accident or misuse, the starter requires service or

overhaul, the following information will provide the information necessary

Service

When starting engine, note starter motor action. The pinion gear should mesh quickly with flywheel ring gear and spin engine. Once engine starts and solenoid opens, the starter should disengage and stop. If starter cranks engine slow, or not at all, check start circuit

components. Failure to crank is normally caused by low

battery charge, defective battery cables, corroded or

poor connections, or these variables, starter continues

must be removed and repaired.

Starter Removal

[-I

death. Disconnect the negative battery cable and spark plug wires while servicing engine, controls,

ciated equipmenf.

will

require

to

low

Accidental starting

result in severe personal injury

little

or no service other

perform this service.

temperatures.

If

after checking

to

crank slowly, starter

of

the engine can

if

through

or

asso-

or

1.

Remove both battery cables from battery. Disconnect ground cable first.

2.

Disconnect battery cable and electrical lead wires

from starter.

3.

Remove blower housing and cylinder air housing.

4.

Remove flywheel and starter motor.

Starter Disassembly

1.

Remove through-bolts and separate end cap, housing, and armature (see Figure

2.

Disassemble drive assembly and drive end cap by loosening the self-locking stop nut.

3.

Inspect starter for damaged or worn parts.

4.

Repair or replace all damaged or worn parts, as

needed.

(Inertia

Type)

1).

Starter Assembly (Inertia Type)

1.

Before reassembling the starter, wipe from parts with compressed air.

a

clean cloth or blow

off

with filtered,

any dirt

STOP

NUT

PINION

GEAR

FIGURE

SEAL

BRUSHES

'

INPUTSTUD

NUT

1.

STARTER MOTOR (INERTIA

9-1

BRUSH

SCREWS

TYPE)

HOUSING

I

/

ES-1334

2.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Assemble brushes

so

that the chamfered side is

away from the brush springs. Make sure brush

do

wires

3. Torque brush screws to a value 5

4.

Torque input stud nut

7

not rub against the commutator or end cap.

of

3

to

Nm).

to

a value of 4 to 5 ft-lbs

Nm).

3.5 ft-lbs

(4tO

(5

to

Starter

1.

Disassembly (Solenoid

Shifl

Type)

Remove "M" terminal nut and wire lead from solenoid (Figure 2).

2. Remove the

two

solenoid mounting screws and

remove solenoid.

5.

Apply a thin film of grease to the commutator end of

to

the armature shaft and

the portion of the shaft that

contacts the bearings. Apply a generous film of

(GE

silicone base grease

Versilube 322-L) to the

shaft threads.

6.

Torque stop nut

to a value of 20

to

25

ft-lbs

34 Nm).

7.

Torque through bolts to avalueof

8

Nm).

8.

Apply a small amount of a silicone based grease

(GE

Versilube 322-L) to armature shaft spline.

9.

Install dust cap, pinion gear, dust cover spacer,

4.5

to 6 ft-lbs

anti-drift spring, stop nut washer, and stop nut.

10.

Push dust cover on until

FRONT

BRACKET

SCREW

it

snaps into position.

\

LEVEF

RETAINFR

mn

(27

to

(6

to

SOLENOID

\

3. Scribe a mark across frame and rear bracket to aid in assembly. Remove the two through bolts.

4.

Remove rear bracket and frame assembly.

5.

Carefully remove armature and lever from front bracket. Note direction of lever and retainer.

6.

Remove the two brush mounting screws, and remove the rear bracket.

7.

Remove brush holder assembly from the frame by pulling the brushes out.

THROUGH

BOLT

/

BUSHING

SEAL

I

.nn"T"

C.T

31

urrcn

(RETAINING

RING)

FIGURE

\

OVERRUNNING

CLUTCH

2.

STARTER MOTOR

GAP

-.

..

ADJUSTMENT

WASHERS

FRAME

ASSEMBLY

9-2

BRUSH

(SOLENOID

HOLDER

SHIFT TYPE)

\

ASSEMBLY

RFAR

. . -.

..

.

BRACKET

C

SCREW

ES-1665

8.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Push stopper toward pinion and remove snap ring

(Figure

9.

Remove stopper and overrunning clutch from

3).

armature shaft.

n

U

/--

PU

OVERRUNNING

\

STOPPER

CLUTCH

FIGURE

10.

Inspect starter for damaged or worn parts.

11.

Repair or replace all damaged or worn parts, as

3.

REMOVING OVERRUNNING CLUTCH

needed.

Starter

Assembly

1.

Install seal in nose housing. Install overrunning

(Solenoid

Shifl

Type)

clutch on the armature shaft.

2.

Slide stopper on the armature shaft. Position snap ring in groove in armature shaft.

Es-1622

SNAP

RING

FIGURE

4.

Lubrication: When starter motor is assembled apply grease to each mended grade; Multemp PS No.

0

Armature shaft spline

4.

INSTALLING STOPPER

of

the following points (Recom-

2):

Both bushings (Both ends of armature) Stopper on armature shaft Pinion gear

0

Sliding portion of lever

5.

Fit overrunning clutch into lever, and install with armature in the front bracket.

6.

Install lever retainer and spacer. Position frame assembly over armature on the front bracket.

7.

Install brush holder assembly. Position brushes in brush holder. Make certain positive lead wires are not grounded.

I

ES-1194

3.

Pull stopper all the way over snap ring (Figure may be necessary to tap snap ring into groove with a punch while maintaining tension on stopper.

4

4).

It

9-3

8.

Install washers, as required, on the rear end of armature shaft to obtain an armature shaft thrust gap

of

0.05

to

0.5

mm

(0.002

to

0.02

inch). New

if

washers are required

Solenoid

Brush Retaining Screws

Through

9.

Install rear bracket. Secure brush holderto rear

Screws

Bolts

rear bracket is replaced.

6

5.7

4

Nm

(54

(33

(51

in.-lb.)

bracket with two machine screws.

10.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Install and tighten the two through capscrews.

11. Install solenoid plunger in lever. Secure solenoid to front bracket with two machine screws.

12. Install wire lead to the terminal

13.

After assembly, adjust pinion clearance. Pinion clearance should be 0.020 to

2.0

mm);

if

not, check as follows. See Figure

A. Connect starter to a battery (Figure

“M”

on solenoid.

0.080

inch

5).

switch. This will shift pinion into cranking

position.

B.

Push pinion back by hand and measure pinion

not

clearance. If clearance does

fall within the specified limits, adjust by adding or removing shims located between solenoid and front bracket. Adding shims decreases clearance; removing shims increases clearance. Shims are included with replacement solenoid.

PINION

-/

(0.5

5.

Close

to

w

FIGURE

hpecting

6.

TESTING ARMATURE FOR GROUNDS

for

an

Open

Circuit

in

Armature:

ES-1001

Using an

ohmmeter, check for continuity between the commutator

If

there

is

segments.

no continuity (high resistance), the

segments are open and armature must be replaced.

Testing Armature

locating shorts

for

a

Short

Circuit:

in

the armature. Place armature

Use a growler for

in

growler and hold a thin steel blade(e.g. hacksaw blade) parallel to the core and just above it whileslowly rotating

armature in growler.

to

blade

vibrate and be attracted to the core.

is shorted, replace with a new one (Figure

A

shorted armature will cause the

If

armature

7).

FIGURE

5.

PINION CLEARANCE ADJUSTMENT

Inspection and Testing

Inspect the starter components for mechanical defects before testing for grounds or shorts.

Testing Armature

for

Grounds:Touch armature shaft or core and the end of each commutator bar with a pair ohmmeter leads. A low ohmmeter reading indicates a grounded armature. Replace grounded armature. See

Figure

6.

i+

PINION CLEARANCE

ES-1623

of

9-4

FIGURE

H

7.

TESTING ARMATURE

FOR

SHORT CIRCUITS

.ER

ES-1002

Commutator Inspection:

Redistribution or publication of this document, 

by any means, is strictly prohibited.

colored, clean with number

paper,

Blow grit out of armature after

If

commutator is scored, rough, or worn, turn it down in a

lathe.

Inertia type starter inspection Housing Inspection:

of

inside of cracks.

the housing. Magnets must be secure and free

If

commutator

00

to

is

dirty or dis-

000

commutator

cleaning.

Permanent magnets are glued to

Check

for

shorts between positive side

If

and brush holder base.

holder assembly. Check for free movement of brushes.

All

brushes should move freely

Overrunning Clutch:

wear or damage.

If

pinion gear is worn or damaged, inspect flywheel ring gear also. Rotate pinion. It should turn free when turned in one direction, and lock when turned in the opposite direction.

there is continuity, replace

in

Inspect pinion

of

brush holder

the brush holders.

and

spline teeth for

Brush

1/4

brushes move smoothly in the brush holders. See Figure

teeth, or pinion splined sleeve is damaged replace

Inspection:

inch

(6.35

8.

Pinion Gear:

pinion gear and dust cover assembly. If pinion gear is in good condition, wipe armature shaft spline and pinion clean.

Solenoid Field

between brushes. open and must be replaced. With field coil mounted the frame, check for continuity between the field frame. Replace frame assembly if there is continuity.

shifl

Coil:

Use an ohmmeter to check for continuity

If

brushes are worn shorter than

mm), replace them. Check to see that

7

0.25

inch

FIGURE

If

8.

BRUSH

WEAR

LIMIT

pinion gear is badly worn, has broken

type starter inspection

If

there is no continuity, the field coil is

coil

in

and

ACAUT~ON

m

damage. cleaning solutions.

Solenoid:

plunger should return to its original position. While holding plunger between terminals replace thesolenoid (Figure

check pinion clearance.

Do

Push solenoid plunger in and release it. The

TERMINAL'Y

Cleaning overrunning clutch in liquid

cleaning solution will result in starter

not clean overrunning clutch in liquid

all

the way in, check for continuity

"M"

and

"B'.

If

there is no continuity,

10).

After replacing solenoid

TERMINAL'W'

FIGURE

10.

SOLENOID TERMINALS

TERMINAL

"M"

Es-1345

f3rushes:Clean around brushes and holders, wiping all brush dust and dirt.

11.5

mm

(.4528

f

p$q-

FIGURE

If

brushes are worn shorter than

inch) replace them (Figure

\

WEAR

9.

(.4528

LlMlT11*5:fi

/

BRUSH

WEAR

inch)

LIMIT

9).

off

ES-1193

Bushings:

of wear or damage, replace them. Bushing and rear bracket are replaced as an assembly. Check armature shaft thrust gap if rear bracket is replaced.

Remove front bushing by tapping bushing from inside with a bracket. Thread capscrew, same size as tap, into bushing. Using a slide hammer remove bushing from front bracket. Press new bushing into front bracket. care not to distort inside diameter of bushing.

9-5

If either the front or rear bushing show signs

7/16

inch tap.

Do

not remove cap from front

Use

Brush Repkcement:

Redistribution or publication of this document, 

by any means, is strictly prohibited.

at the brush. Be careful not to damage field coil. Clean

1

/4

to

3/8

inch

with sandpaper or emery cloth (Figure

STILL ATTACHED

TO FIELD COIL

Cut old positive brush from pigtail

(6.5

to

9.5

mm)

of

brush end

11).

PIGTAIL

4

(approx.

CLEAN

114

of

to

3/8

pigtail

inch)

_____

*ncSoLDER

SMALL CHAMFER

..,..:.’

LARGE CHAMFER

f

REPLACEMENT

U

MUST

EXTEND BEYOND BRUSH SURFACE

BRUSH

Starter

Before installing starter motor, make sure the starter mounting surface on the engine base is clean and free of oil.

To (Prior to Spec E) engines use the following procedure. On these engines starter pinion gear lash requires adjustment and must be checked when starter is

installed.

1.

Mounting

install starter on B43G (Prior to Spec

Install starter

just enough to hold starter in place.

2.

Remove spark plugs from the engine. This allows

free movement of the flywheel.

motor

and tighten mounting capscrews

C)

and B48G

FIGURE

Push prepared end ment brush from the small chamfered side. Solder pigtail lead to replacement brush on the large chamfered side,

50/50

using 240/325 Watt soldering iron. Use a file to remove any

excess solder that may extend beyond brush surface.

(BCAUTIONI

damage. any excess material from brush surface.

Do

11.

BRUSH REPLACEMENT

of

pigtail lead into hole in replace-

tinllead, rosin core solder and a standard

Ma ferial protruding sudace

not use excessive solder

of

brush can cause equipment

from

solderedside

or

heat

and

file

3. Manually pull the starter pinion gear outward shaft until pinion gear teeth mesh completely with

flywheel ring gear teeth. Energize solenoid on

solenoid shift starter.

on

its

9-6

4. Measure the amount

Redistribution or publication of this document, 

by any means, is strictly prohibited.

the pinion gear teeth and the ring gear teeth. See

Figure

slow starter operation, or if lash is greater than

0.035

12.

If

lash

inch (0.889 mm), lash must be adjusted.

of

is

too

FLYWHEEL

free travel (lash) between

tight, causing binding

RING

GEAR

and

To

install starter on B43E (Beginning Spec A), B43G

C),

(Beginning Spec engines starter pinion gear lash does not require adjustment.

1.

use

the following procedure.

Install starter motor and torque mounting capscrews

to 24

to

26

ft-lbs

and B48G (Beginning Spec

On

these engines

(33

to 35 Nm).

E)

STARTER

STARTER MOTOR

PINION

GEAR

FIGURE

5.

To

adjust lash on starters without slotted mounting holes, remove starter. Use a drill to enlarge one mounting hole in starter mounting bracket.

6.

Install starter motor and adjust lash to 0.020 in.

0.015

7.

Remove flywheel and torque starter mounting capscrews to 24 to Onan flangehead capscrews or capscrews with a hardened flatwasher. lockwashers.

in.

12.

CHECKING

(0.51

mm k 0.38 mm).

26

GEAR

FREE

TRAVEL WHEN

-

STARTER

ft-lbs (33 to 35 Nm). Use

GEAR

21

164

inch (8.334 mm)

LASH

SAE

Do

grade

not use

ES-1003

3.

8

2.

Install flywheel, blower housing, and cylinder air housings. For correct cylinder air housing installations (required on some models), refer to Cylinder

Air Housing Clearance.

3. Connect battery cable and wires to starter. Connect battery cables

to

battery. Connect ground cable last.

-1

Failure properly can

and ring gear

damage.

correct values when installing.

8.

Install flywheel spark plugs, blower housing, and

cylinder air housings. For correct cylinder air

housing installation (required on some models), refer

to

Cylinder Air Housing Clearance.

9.

Connect battery cable and wiresto starter. Connect battery cables to battery. Connect ground cable last.

.

io

torque starter bolts

cause

starter failure

-Torque starter bolts to

9-1

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Engine

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Disassembly

DISASSEMBLY/ASSEMBLY

When complete engine disassembly is necessary, first removeall complete assemblies. Individual assemblies such as fuel pump and carburetor can be disassembled and repaired at another time.

Suggested Disassembly Order

1.

Drain crankcase.

2.

Disconnect all exhaust lines and electrical lines.

3.

Remove engine from its mountings and place on a suitable bench or work stand.

4.

Remove all housings, shrouds, blower housings, etc.

5,

Remove flywheel, using a puller.

6.

Remove the gear cover, being careful to protect

the oil seal from keyway damage.

7.

Remove the crank gear, using a gear puller and ring.

8.

Remove all accessories such as oil filter, starter, intake manifold, fuel lines, spark plugs, etc.

9.

Remove breaker point box.

10.

Remove oil base, oil pump and cylinder heads.

11.

Remove valves, springs, lifters, etc.

12.

Remove camshaft and gear assembly.

13.

Remove connecting rods and pistons.

14.

Remove rear bearing plate, crankshaft, and front bearing.

Keep all parts in their respective orders. Keep valve assemblies together. Return rod caps to their respective pistons. Analyze the reasons for parts failure.

Suggested Assembly Procedure

Engine assembly is normally the reverse disassembly procedure, observing proper clearances and torques. Use a torque wrench to assure proper tightness. Coat the internal engine parts with oil they are assembled. After the internal engine parts are assembled, the engine should turn over by hand freely. Use onlygenuine Onan partsand special tools when reassembling your engine.

of

the

as

1.

Use the proper bearing driverto install front main bearing after coating

2.

Insert rear main bearing in rear bearing plate.

3. Insert crankshaft,rear bearing plate, and crankshaft gear.

4.

Install piston and connecting rods.

5.

Install camshaft and gear assembly; align crank gear mark with cam gear mark.

6.

Install valve assemblies, oil pump, oil base, and cylinder heads.

7.

Install breaker point box.

8.

Install all accessories such as oil filter, starter,

fuel lines and spark plugs.

9.

Install gear cover with oil seal and flywheel.

10.

Set breaker points to obtain proper timing.

11.

Check valve clearance.

12.

Install all housings and air cleaner.

13. Fill crankcase with oil.

it

with a light film of oil.

Operation

Start engine and check oil pressure. Run for approx-

imately 15 minutes to bring engine to operating temperature. Check for oil leaks, fuel leaks and exhaust leaks. Adjust carburetor and governor for speed and sensitivity.

Testing Compression

The compression tester

condition of valves, pistons, piston rings and cylinders.

To check compression:

1.

Run the engine until thoroughly warm.

2.

Stop engine and remove spark plugs.

3. Remove air cleaner and place throttle and choke in the wide open position.

4.

Insert the compression gauge in one spark plug

hole.

5.

Crank the engine and note the reading.

Refer to pressures. There may atmospheric conditions and altitude. These pressures are for a warm engine at cranking speed (about

rpm).

SPEClFlCA

is

used

to

determine

TlONS

section for compression

be

variations due to temperature,

the

300

10-1

Tappet Adjustment

Redistribution or publication of this document, 

by any means, is strictly prohibited.

The engine is equipped with adjustable valve tappets. The valve tappet clearance should be checked and adjusted, if necessary, at least every

200

operating hours or when poor engine performance is noticed. Adjust the valve clearance only when engine is at

ambient temperature. Proceed as follows:

1.

Remove ignition key to prevent accidental starting.

2.

Remove all parts necessary to gain access to valve tappets.

3.

Remove spark plugs to ease the task

of

turning

the engine over by hand.

4.

Place a socket wrench on the flywheel capscrew and rotate the crankshaft in a clockwise direction until the left intake valve (viewed from flywheel end) opens and closes. Continue turning the crankshaft until the TC mark on the flywheel is

lined up with the TC mark on the gear cover. This

(#1)

should place the left piston

at the top of its compression stroke. Verify that the left intake and exhaust valves are closed and there is no pressure on the valve lifters.

The correct feeler gauge for the valve adjustment

5.

(see SPEClFlCATl0NS)shouId pass freely between valve stem and tappet; a

0.002

inch

(0.05

mm)

thicker gauge should not (Figure 1).

6.

To correct the valve clearance, use a 7/16-inch

the

open end wrench to turn

adjusting screw

obtain the correct clearance. The screw

locking and will stay where

it

is set. A 9/16-inch

is

to

self-

(14 mm) open end wrench is required to hold the

tappet while turning the adjusting screw.

VALVE

A

properly functioning valve system isessential for good

engine performance.

valve design as shown in Figure

SYSTEM

All

engines utilize an L-head type

1.

Access

to

the valve system can be obtained by removing the cylinder heads and thevalve coverson top of the engine. Avalvespring compressor must be used to remove valves from the cy1 i nder block.

A

valve stem seal is used on the intake valve guides of some engines. This seal must be replaced each time the valve is removed.

Place valves, springs, retainers, and tappets in a rack they are removed from cylinder block

so

they can be

as

identified and reinstalled in their original locations. Discard old valvestem seals and replace with new ones during assembly.

Use the following procedures to inspect and service the valve system.

Inspection

Clean carbon from the valves, valve seats, valve

guides, and cylinder block.

Valves:

Check the valve face for evidence of burning,

warpage, out-of-round, and carbon deposits.

Burning and pitting are caused by the valve failing to seat tightly. This condition is often caused by hard carbon particles on the seat. It may also be due to weak valve springs, insufficient tappet clearance, warpage, and misalignment.

t

7.

To

adjust valves on the right hand cylinder, turn engine one complete revolution and again line up mark on the flywheel and the TC mark on the gear cover. Then follow adjustment procedure given for left hand cylinder.

8.

Replace all parts removed in Step

2.

Tighten all screws securely. Torque manifold bolts to specified torque.

USEA STANDARD AUTOMOTIV

NOTE:

WRENCH TO ADJUST THE TAI

,

VALVE

'ETYPE VALVE CLEARANCE 'PETS.

CTT

J

SEAT

pj

I

E

VALVESPRING,

''

I

FIGURE

VALVE RETAINER

ONLY) SEAL

1.

VALVE

ASSEMBLY

VALVE ADJUnlNG

SCREW

ALVE ROTATOR

VT-1005

I

10-2

Warpage occurs chiefly in the upper stem due

Redistribution or publication of this document, 

by any means, is strictly prohibited.

exposure to intense heat. Out-of-round wear follows

when

the

seat

is

pounded

not

in

line with the stem and guide.

by

a

valve

whose head is

If

a

valve face

to

its

is

-1

Driving

out

old valve guides can cause

guide and tappet bore damage. not strike guide or tappet bores removal.

wiih

driver during

Do

burned or warped, or if the stem is worn, install a new

valve.

+

Too much clearance in the intake guide admits air and

oil

into the combustion chamber, upsetting carburetion, increasing oil consumption, and making heavy carbon deposits. Carbon reduces heat dissipation. Clean metal is a good heat conductor but carbon insulates and retains heat. This increases

combustion chamber temperatures which causes

Valve Guide Installation:

covered with crocus cloth through valve guide holes to clean out carbon and other foreign materials. Place a new gasket on the intake valve guide, and coat the outer edgeof each new guide with in cylinder block and press in until guide stops or protrudes block. Figure

11

132

inch

A

suggested method

3.

Run a small polishing rod

oil.

Placeguide, notch-up,

(8.7

mm) from rocker box side of

of

installation is shown in

warping and burning. Unburned carbon residue gums valve stems and

causes them to stick in the guide. Deposits of hard carbon with sharp points projecting become white hot and cause pre-ignition and pinging.

Refinish valves that areslightly pitted or burned on an accurate valve grinder.

If

valves are badly pitted or

have a thin margin when refacing, replace them.

VT-1020

FIGURE

Stems And Guides:

guidesfor wear as shown in Figure

2.

VALVE STEM AND VALVE GUIDE INSPECTION

Always check valve stems and

2.

Use a hole gauge to measure the valve guide. When clearance with stem exceeds original clearance by that specified in

AND

ENSlONS

CLEARANCES

replace either valve or

DIM-

guide or both, as may be necessary. Always regrind seat to make concentric with the newly installed guide.

5/16-18

(2

ROD

HEX, NUT

5/16

(2

\

FLAT WASHER REQUIRED)

VT-1023

Worn valve stem guides can be replaced from inside the valve chamber (a seal is provided behind the intake valve guides only). The smaller diameter of the

4

tapered valve guides must face toward the valve head. Tappets are also replaceable from the valve chamber after first removing the valve assemblies.

Valve Guide Remova1:Before

use an electric drill with a wire brush to remove carbon and other foreign material from top surface of guides. Failure to perform this operation may result in damage to the guide bores. Drive the guides out with a hammer and valve guide driver.

removing valve guides,

FIGURE

Valve Stem Seals:

3.

VALVE GUIDE INSTALLATION

Do

not reuse valve stem seals. Each

time the valves are removed from cylinder block, a

new seal must be used when valve is reinstalled.

[BCAUTIONI

Removing a valve after installing valve

stem sealcan cause sealdamage. not allow valve stem groove to come in contact with valve sfem seal after installation.

10-3

Do

Value

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Spring:

Check valve springs for cracks, worn ends, distortion, and tension. If spring endsare worn, check valve spring retainer for wear. Check for spring distortion by placing spring on aflat surface next to a square. Measure height of spring and rotate

it

against square edge to measure distortion. If distortion exceeds

0.06

inch

(1.5

mrn) replace spring. Check spring tension at the installed height for both the valve open and closed position using an accurate valve spring tester. Replace any valve spring that is weak, cracked, worn, or distorted.

Valve Seat Removal:

Remove carbon and combustion deposits from valve seat. Select proper puller size determined by inside diameter

of

valve seat. On some pullers use a new seat as a guide to adjust puller depth (Figure

4).

Puller jaws must expand into cylinder block at the point where bottom of valve seat insert rests on cylinder block (Figure and tighten hex nut. Clamp cylinder block to

4).

Position puller on valve seat

a

solid bench. Attach slide hammer to puller. Tighten hex nut between each blow with the slide hammer.

*

Valve Rotators:

Positive type valve rotators prolong valve life and decrease valve repairs. When functioning properly, the valve is rotated a fraction of a turn each time it opens. While at open position, the valve must rotate freely. There is no easy way to determine if a valve rotator is good or bad. Onan recommends that valve rotators be replaced at each major overhaul or

a build-up

of

carbon

is

noted on

if

valve face and valve seat.

Walve Seats:

Inspect valve seat inserts. If seats are loose, cracked or severely pitted, new ones must be installed. Remove valve seat inserts using a valve seat removal tool. If valve seat insert bores in cylinder

so

block are damaged or worn

that a press fit cannot be obtained when installing new standard size valve seat inserts, the bores must be machined for an

oversize seat.

USE

NEW

ADJUST

VALVE SEAT

PULLER

TO

DEPTH

VAL

L

CHECK THIS SURFACE

FOR

BURRS BEFORE

INSERTING SEAT

PULLER

JAWS

FIGURE

4.

VALVE

SEAT

REMOVAL

C-1104

FIGURE

Valve Seat Installation:

5.

INSERTING NEW VALVE SEAT

After the old seat has been

removed, clean out any carbon or metal burrs from the

seat insert recess. Use a valve seat insert driver and

5).

hammer to install the insert (Figure

seat insert in

so

that the insert enters the recess evenly.

Drive the valve

Make certain that the valve seat insert rests solidly on

the bottom of the recess all the way around its

circumference.

Insert valve seat staker into valve seat or guide in cylinder block. Using a lead hammer, strike the staking tool asharp blow

It

will

in place.

be

to

wedge new valvesecurely

necessary to refinish valve seat

inserts before installing valves. To

assure a tight valve seat fit and eliminate the

of

danger

seat loosening in the bore, valve seat must

be staked.

10-4

VT-1

ow

*

b

TAPPETS

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Very little wear takes place on tappet diameters or in

If

the

tappet bores.

bore in cylinder block exceeds specifications, replace

the tappet.

*

,

Inspect the tappet faces which contact camshaft lobes for roughness, scuffing, or concave wear. Replace any worn tappets. If tappets are worn, inspect camshaft for wear.

clearance

between tappet

and

VALVE FACE AND SEAT GRINDING

Some engines are equipped with a premium valve package (aluminized intakevalves). valve face does not clean-up using a wire brush, the valve face may be refinished. This removes the aluminized coating from thevalveface. An aluminized valve that has been refinished will normally have a life expectancy equal to a standard valve. If longer valve life is required, worn or damaged valves should be replaced with new premium valves.

Before installing new valves or previously used valves, inspect valve seats for proper valve seating.. If used valves are reinstalled, the valve stems should be

cleaned and valve faces ground to their specified angles of 44". Refinish valve seats to a 45" angle. When refacing valves and seats, remove all evidence of pitting and grooving. or worn, true very light grind is usually enough to square stem and

remove any pits or burrs. The valve guide should be thoroughly cleaned. If valve guide is worn, or valve is warped, the necessary parts must be replaced.

it

and clean

If

end of valve stem is pitted

it

up

If

the aluminized

on

the refacer wheel.

A

Refinish valve faces to a 44" angle on a valve refacing machine. The first cut from valve face grinding. Check if there is an unevenness of metal being

removed.

check to see if valve is properly seated in machine or valve is warped, worn, around the whole valve face, keep grinding until complete face is ground clean. Be sure the correct valve

face angle is maintained. When valve head

knife edge will be ground (Figure head due to the large amount of metal that must be removed to completely reface valve. Heavy valve heads are required for strength and good heat dissipation. Knife edges lead due to heat localizing on the edge.

Replace any valve that cannot be entirely refaced while keeping a good valve margin (Figure worn, or damaged in any way. The amount of grinding necessary to true a valve indicates whether valve head is worn or warped.

If

only

part

of

valve's

or

to

breakage, burning, and pre-ignition

WARPED

WITH

VALVE KNIFE EDGE KNIFE EDGE

GOOD MARGIN

face

distorted. When cut is even

must

be a light

has

been

touched,

is

warped, a

7)

on part or all of the

7)

or is warped,

if

74

1/16

By

grinding the valve face and seat at slightly different angles, a fine line of contact on face and seat is obtained, eliminating the need to lap the seating surfaces. The one degree difference in angles is defined as

the interference angle (Figure 6). The seat angle is

greater than that of the valve face. This assures contact at the maximum diameter on valve seat seating surface.

FIGURE

7.

1

I

VALVE

HEAD

INCH

(1.6mm)MlNlMUM

M-1114

MARGIN

FIGURE

6.

VALVE INTERFERENCE ANGLE

VT-1021

When new valve seats are installed, or previously used seats reground, refinishing must be done with a valve seat grinder used according to the manufacturer's directions.

Valve seats should be ground with a 45 degree stone

and the width of theseat band should be 1/32 inch to 3/64 inch to assure proper seating.

Place each valve in its proper location. Check each valve for a tight seat. Make several marks at regular intervals across the valve face using machinist's bluing. Observe if the marks rub off uniformly when the valve is rotated part of a turn against the seat. The valve seat should contact the valve face evenly at all points. The line of contact should be at the center of

the valve face.

(0.79

to 1.2 mm) wide. Grind only enough

10-5

FLYWHEEL

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by any means, is strictly prohibited.

GEAR

COVER

Removing the flywheel isa relatively simple process, but the following procedure must be followed to avoid damage to the gear case and possible injury to the operator.

1.

Turn the flywheel mounting screw outward about two turns.

pAEI

Incorrect flywheel removal can

result in severe personal injury.

Do

not remove flywheel screw completely when

using flywheel puller.

2.

Install a puller bar on the flywheel as shown in Figure

8.

FLYWHEEL

After removing the mounting screws, tap the gear cover

gently with a

soft

faced hammer to loosen it (Figure

9).

When installing the gear cover, make sure that the pin

in the gear cover engages the nylon lined (smooth) hole in the governor cup. Turn the governor cup

so

that the nylon lined hole is at the three o’clock position. Use a small amount of grease to assist in holding governor cup in position. The smooth side of the governor yoke must ride against the governor cup. Turn the governor arm and shaft clockwise as far as possible-and hold in this position until the gear cover is installed flush against the crankcase. Be careful not to damage the gear cover oil seal.

c

MOUNTING

U

FIGURE

3.

Turn the puller bar bolts in, alternately, until the

8.

BLOWER WHEEL PULLEY

SCREW

cs-lo00

wheel snaps loose on the shaft.

-1

Improper flywheel removal can cause gear case damage.

tools

use any

to pry against gear cover when

removing iiywheel.

4.

Unscrew the puller from the flywheel, remove the

flywheel mounting screw and washer and pull the

off

the

shaft.

flywheel

A

wheel.

bent

or

Take care not to drop the

broken fin will destroy the balance.

Always use a steel key for mounting the flywheel.

Do

not

ROTATE

GOVERNOR CUP

SO

THAT ROLL PIN’

FITS INTO THE

METAL LINED

OR

HOLE

EUSH~G

PLASTIC

IN

THE

FIGURE

ROLL PIN

CUP

I

9.

\+GOVERNOR

/,I

I

GEAR

COVER

GOVERNOR

SHAFT YOKE

(Smooth Side

Toward Cup)

UI

IF FEELER WILL

ENTER HOLE

BALL HAS

FALLEN OUT

ASSEMBLY

L

ARM

aEAL

112”

10-6

WHEN GOVERNOR

Redistribution or publication of this document, 

by any means, is strictly prohibited.

IS

PROPERLY

ON

ORAWING WILL

BE

AS INDICATED

L.-

/’

1

5

BALL

RIGHT

GOVERNOR

INSTALLATION

6

BALL GOVERNOR

FLYBALL

OF

BALLSPACER

LOCATIONS

v

WRONG

8

BALL GOVERNOR

C-1107

CS-1238

FIGURE

GOVERNOR

CUP

With the gear cover removed, the governor cup can be

taken

off

after removing the snap ring from the camshaft center pin. Catch the flyballs while sliding the cup (Figure

10).

Replace with a new part any flyball which is grooved or

if

has a flat spot; the ball spacer

its arms are worn or otherwise damaged; the gear/spacer assembly if loose on gear hub, and the governor cup

if

the race surface is

grooved or rough. The governor cup must be a free-

fit

spinning

on the camshaft center pin, but without any

excessive play.

10.

GOVERNOR

off

CUP

DETAILS

cannot be pulled outward or removed without damage.

If

the center pin extends out too far, the cup will not hold

If

the flyballs properly.

(5.6

mm), (the engine will race, especially at no load)

the distance is less than

7/32”

remove the center pin and press in a new pin.

TIMING

If replacement of either the crankshaft gear

GEARS

or

the camshaft gear becomes necessary, always install both gears new.

The camshaft and gear must be replaced as an assembly. Before removing the camshaft and gear assembly,

If

replacing the ball spacer, be sure to position it

so

an arm is lined up with the space on the camshaft gear (if your camshaft gear does not have a space in it,

remove the cylinder head and valve assemblies. Then remove the operating plunger for the breaker points and

tappets. disregard this paragraph). If the ball spacer arm is not lined up with the space in the camshaft gear, a flyball can slip into the space and cause engine racing and governing problems (Figure 10).

4

When installing the governor cup, tilt the engine gear is up, put the flyballs in place (Figure

lo),

so

the

and

install the cup and snap ring on the center pin.

4

314

inch

(19

The camshaft center pin extends out

of

from the end

in-and-out travel distance

the camshaft. This distance provides an

of

7/32

inch

(5.6

mm)

mm) for the governor cup, as illustrated. Hold the cup against the flyballs when measuring. The camshaft center pin

To remove the crankshaft gear, first remove the snap ring and retainer washer, then attach the gear pulling ring using two

No.

10-32

screws (Figure

11).

Tighten

the screws alternately until both are tight. Attach a gear

to

puller Each timing gear is stamped with

gear teeth must mesh

the puller ring and proceed to remove the gear.

“0”

near the edge. The

so

that these marks exactly

coincide when the gears are installed in the engine.

When instalfing the camshaft gear and shaft assembly,

be sure that the thrust washer is properly in place behind the camshaft gear. Then install the crankshaft retaining washer and lock ring.

10-7

CRANKSHAFT

Redistribution or publication of this document, 

by any means, is strictly prohibited.

FIGURE

11.

TIMING

GEAR

PULLER

GEAR

REMOVAL

AND

INSTALLATION

E MARKS

LIGN WHEN ING TIMING EARS

VT-1029

4. Turn the crankshaft until the piston is at the bottom of its stroke and remove the connecting rod nuts. Lift the rod bearing cap from the rod and push the rod and piston assembly out through the top of the cylinder using a hammer handle. Avoid scratching the crankpin and cylinder wall when removing the piston and rod.

so

Mark each piston and rod assembly

they can be returned to their respectivecylinders after overhaul. Keep connecting rod bearing caps with their respective rods.

5.

Remove the piston rings from the piston with a piston ring spreader asshown in Figure 13. Remove

the piston pin retainer and push the piston pin out.

L

PISTONS AND CONNECTING RODS

Observe the following procedure when removing pistons

and connecting rods from the engine.

1.

Drain Oil.

2.

Remove the cylinder head and oil base pan from the engine.

3.

Remove the ridge from the top of each cylinder with a ridge reamer before attempting piston removal (Figure

1-

reamer to remove cylinder ridge before removing piston.

12).

Improper piston removal can cause piston damage. Use ridge

FIGURE

13.

REMOVING

PISTON

RINGS

Remove dirt and deposits from the piston surfaces with an approved cleaning solvent. Clean the piston ring grooves with agroove cleaner or the end

of

a piston ring filed to a sharp point (Figure 14). Care must be taken not to remove metal from the groove sides.

FIGURE

12.

REMOVING

RIDGE

FROM

CYLINDER

ACAUT~ON

m

cleaning solvent

Improper pisfon cleaning can cause piston damage.

or

wire

brush

Do

nof use a caustic

for

cleaning pistons.

When cleaning the connecting rods in solvent, be sure to include the rod bore.

Blow

out all passages with

compressed air.

104

82

Redistribution or publication of this document, 

by any means, is strictly prohibited.

1

FIGURE

14.

PISTON GROOVE CLEANING

FIGURE

15.

CHECKING RING

SIDE

CLEARANCE

with deep nicks, signs of fractures, scored bores or bores out of round more than inch.

2.

Use a new piston pin to check connecting rod

A

for wear.

push fit clearance is required and

varies from engine to engine. If a new piston

pin falls through a dry rod pin bore as a result

of its own weight, replace the rod.

Fitting Pistons:

0.002

Inspection

Follow the procedures given below when inspecting pistons and connecting rods.

Piston Inspection:

1.

Inspect the pistons for fractures at the ring lands, skirts and pin bosses. Check for wear at

the ring lands using a new ring and feeler gauge

15.

as shown in Figure

the side clearance of the top compression ring

exceeds that specified in

CLEARANCES.

2.

Replace pistons showing signs of scuffing, scoring, worn ring lands, fractures or damage from preignition. Excessive piston wear near

of

the edge

the top ring land indicates

preignition.

Connecthg

1.

Replace connecting rod bolts and nuts with

Rod

Inspection:

damaged threads. Replace connecting rods

Replace the piston when

DIMENSIONS AND

1.

Proper piston tolerances must be maintained

for satisfactory operation.

2.

Refer to

DIMENSIONS AND CLEARANCES

.

determine where to measure piston to be sure

the total clearance follows specifications.

1

I

Io

c

FIGURE

0

MEASURECLEARANCEHERE

16.

MEASURING

0

PISTON

I

01

CLEARANCE

to

10.9

fitting Piston Rings:

Redistribution or publication of this document, 

by any means, is strictly prohibited.

1.

Install the piston ring in the cylinder bore. Invert the piston and push the ring to the end of ring travel, about halfway into the bore, which trues the ring end gap. Check the gap with a feeler gauge (Figure

2.

The practice

end gap

17).

of

filing ring ends to increase the

is

not recommended. If the ring end

gap does not meet specifications, check for

the correct set of rings and the correct bore

size A cylinder bore that is

(0.03

mm) under size will reduce the end gap

0.003

inch

(0.08

mm).

0.001

inch

Cleaning

After removing pistons, crankshaft, cylinder heads, etc., inspect block for cracks and extreme wear. If

block is still serviceable, prepare

it

for cleaning as

follows:

1.

Scrape all old gasket material from block. Remove oil by-pass to allow cleaning solution to contact

inside of oil passages.

2. Remove grease and scale from cylinder block by agitating in .a bath of commercial cleaning

or

solution

3.

Rinse block in clean hot water to remove cleaning

hot soapy washing solution.

solution.

Inspection

When rebuilding theengine, thoroughly inspect block for any condition that would make use. This inspection must be made after all parts have been removed and block has been thoroughly cleaned and dried.

1.

Makeathorough check forcracks. Minutecracks may be detected by coating the suspected area

with a mixture of 25 percent kerosene and 75

percent light motor oil. Wipe the part dry and immediately apply a coating of zinc oxide (white lead) dissolved in wood alcohol. If cracks are

present, the white coating will become discolored at the defective area. Always replace a cracked cylinder block.

it

unfit for further

,

L

FIGURE

17.

POSITIONING OF PISTON RING AND MEASURING

CYLINDER

OF

BLOCK

END GAP

The cylinder block is the main support for all other basic engine parts. Crankshaft and camshaft are supported by the block, assuring alignment of the crankshaft and cylinder bores.

2.

Inspect all machined surfaces and threaded holes. Carefully remove any nicks

or

burrs from machined surfaces. Clean out tapped holes and clean up any damaged threads.

3.

Check top of block for flatness with a straight edge and a feeler gauge.

CyMnder Bore Inspection:

Inspect cylinder bores for scuffing, scratches, wear, and scoring. If cylinder bores are scuffed, scratched, scored, or worn, they must be rebored and honed for the next oversize piston.

When the appearance of cylinder bores is good and thereare noscuff marks, check cylinder bore forwear or out of roundness as follows:

1.

Check cylinder bore for taper, out of round, and

wear with a cylinder bore gauge, telescope gauge

or inside micrometer. These measurements

should be taken at four places, top and bottom of

piston ring travel, parallel and perpendicular to

axis

of

crankshaft.

Record measurements taken at top and bottom of

2.

piston travel as follows (Figure

18):

10-10

A.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Measure and record as

“A”

the

cylinder bore

diameter (parallel to crankshaft) near the top

of

cylinder bore where greatest amount

wear occurs.

of

TOP END

OF

CY

LlNDER

B.

Also

measure and record as “B”cy1inder bore

diameter (parallel to crankshaft) at the bottom

of

piston travel.

C.

Measure and record as

“C”

cylinder bore

diameter (perpendicular to crankshaft) near

of

the top

cylinder bore where greatest

amount of wear occurs.

D.

Also measure and record as

“D”

cylinder bore diameter (perpendicular to crankshaft) at the bottom of piston travel.

E.

Reading ”A’subtracted from reading

“C”

reading

subtracted from reading

“B”

indicates cylinder taper.

If

cylinder taper exceeds that specified in

ENSlONSAND CLEARANCES

rebore and hone

cylinder to the next oversize

and

“D”

DIM-

e418

BOTTOM

OF

RING

TRAVEL

RING

,WEAR

AREA

F.

Reading

reading whether

round exceeds that specified in

AND CLEARANCES,

rebored and honed to the next oversize.

“A’

compared

“B’

compared

or

not cylinder is out of round.

to

reading

the cylinders must be

“C”

and

“D”

indicate

If

out of

DlMfNSlONS

A

reboring machine is used when going to oversize pistons.

FIGURE

Reboring

Rebore and hone engine whenever cylinder bore is worn, damaged, out

exceeds specifications.

b

4

resized which it will clean up.Thefinalfinishand borediameters should then be obtained by honing. Final bore diameter

should equal the standard diameter added to the

oversize.

the

Cylinder

of

round,

A

worn cylinder bore should be

to

the smallest standard oversize diameter at

or

if

cylinder taper

After boring

dimension piston and ring clearance should be appropriate. There is no need to adjust or“fit” pistons and rings.

When reboring cylinders, take the following precautions:

1.

Make

using

Improper boring

k@%!@!l

damage. Boring

qualified mechanics.

wi//

musf

resulf

be done

in

engine

by

2.

Be

free.

18.

METHODS OF

A

to

the correct oversize cylinder bore

sure cutting tool

it.

sure

top

of

engine block is smooth and deposit

OF

CYLINDER BORE

MEASURING THE DIAMETER

is

properly ground

before

10.1

1

3.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Clean base of boring bar before bar is set up. Deposits under boring bar will cause

it

to

tilt and

the cylinder will be distorted after boring.

4.

Makean initial roughcut,followed byafinishcut.

to

Then hone cylinder bore

the specified oversize.

Deglazing Cylinder Bores

Deglaze the cylinder bores if there are no scuff marks and no wear or out of round beyond specifications before installing new rings. Deglazing gives a fine

so

finish, but does not enlarge cylinder diameter,

the

original pistons with new rings may still be used.

1

Honing Cylinders (Using Precision Hones)

Refer to hone manufacturer’s recommended grit size to

40

RMS.

produce specified surface finish of 20 to

Too

rough of a finish will wear out the rings and cause excessive oil consumption and too smooth of afinish can retard piston ring seating.

1.

Position block solidly for either vertical or horizontal honing. Use either a drill press or heavyduty drill which operates at approximately 250 to

450

rpm.

2.

Follow hone manufacturer’s instructions for the use

of

oil or lubricant on stones.

Do

not use

lubricants with a dry hone.

3. Insert hone in bore and adjust stonestofit snugly to the narrowest section. When adjusted cor-

or

rectly, the hone should not shake

chatter in cylinder bore, but will drag freely up and dowg when hone is not running.

The reason for deglazing a cylinder is to provide

to

cavities

1.

Wipe cylinder bores with a clean cloth which has

hold oil during piston ring break-in.

been dipped in clean, light engine oil.

2.

Use a brush type deglazing

to

bristle tips

produce a crosshatch pattern in the

tool

with coated

cylinder bore.

3.

Use a slow speed drill Move deglazing tool up and down in cylinder

12

complete strokes) rapidly enough to obtain a

crosshatch pattern (Figure

to

drive the deglazing tool.

19).

(10

to

L

4.

Connect drill to honeand start drill. Feel out bore for high spots, which cause an increased drag on stones. Move hone up and down in bore with short overlapping strokes about

40

times per minute. Usually bottom of cylinder must be worked out first because it is smaller.

As

cylinder

takes a uniform diameter, move hone up and

down all the way through cylinder bore.

5.

Check diameter of the cylinder regularly during honing.

A

dial bore gauge

is

the easiest method but

a telescoping gauge can be used. Check size at six

places in bore; measure twice at top, middle and bottom at 90-degree angles.

6.

Crosshatch formed by the stones should form an

included angle of 23 degrees. This can be

achieved by moving the rotating hone (250 to450

rpm) up and down in cylinder bore about

40

per minute.

7.

Clean cylinder bores thoroughly with soap, water

A

and clean rags.

clean white rag should not become soiled on wall after cleaning is complete. Do not use a solvent or gasoline since they wash oil from the walls but leave the metal particles.

times

PRODUCE CROSS HATCH SCRATCHES

FOR FAST RING SEATING

19.

FIGURE

I

ACAUTION

CROSS

Improper cylinder cleaning will result in engine damage.

AVOID THIS FINISH

HATCHING

use gasoline, solvents, or commercial cleaners to clean cylinder bores.

4.

Clean cylinder bore thoroughly with soap, water and clean rags. Continue cleaning until a clean

no

white rag shows

discoloring when wiped through

cylinder bore.

Do

not

8.

Dry crankcase and coat it with oil.

10-12

CRANKSHAFT

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Clean

crankshaft thoroughly

scoring, chipping, cracking, or signs crankshaft has overheated, is scored, or excessively

L

worn, reconditioning Examine bearing journals for cracks

or

occurred.

I

Measure crankshaft main bearing and connecting rod

journals at several places on their diameter to check for

roundness and taper.

The only recommended method of reconditioning the

crankshaft

is

regrinding, as required to accommodate undersize bearings. Metallizing not recommended.

If

regrinding of crankshaft journals is necessary, the work should be done by a reputable machine shop that has suitable equipment to handle precision work type. Undersize main bearings are available in sizes of

0.01

0,

0.020,

and

0.030

rods are available in sizes of

0.040

inch.

Whenever making major repairs on the engine, always

inspect the drilled passages

them to remove any foreign material and

proper lubrication

of

the connecting rods.

and

inspect journals

of

overheating.

for

If

replacement will be required.

if

overheating has

of

bearing journals is

of

this

inch. Undersize connecting

0.010,

0.020,

0.030

and

of

the crankshaft. Clean

to

assure

ALIGN

HOLE IN

-------------

BEARING

IN

BEARING BORE

CAWSHAFT BEARING

FIGURE

20.

FRONT

CAMSHAFT

BEARING

7/32'

FROM

(5.6

mm)

OUTSIDE

Replacement camshaft bearings are precision type which do not require line reaming or line boring after installation. Clean outside of the bearing and bearing

bore in the block. Before installing cam bearings use

Locktite Bearing Mount on outside diameter of bearing. Use a combination bearing driver to install bearings.

Place the bearing on the crankcase over the bearing bore with the lubricating hole (front only) in the proper position. Be sure to start the bearing straight. Press in the front bearing flush with the outside end of the bearing bore. Front cam bearing oil hole must line up

20).

with oiling hole in cylinder block (Figure

Press in the rear camshaft bearing until past the ignition plunger hole. Lubricate bearing surfaces with oil after installing.

New crankshaft main bearings are precision type which

do

not

BEARINGS

require line reaming or line boring after installation. Usea press ora suitable driverto remove bearings. Support casting to avoid distortion and to avoid dam-

With camshaft and crankshaft removed, use a micro-

to

meter

measure diameter

dial bore gauge

or

a telescopic gauge and micrometer

of

bearing journals. Use a

to measure inside diameter of bearings. Refer to

DIMENSIONS AND CLEARANCES

to determine

if

clearances are within specifications.

Any bearing that is scored, chipped, pitted or worn

beyond the specified limits must be replaced. Removal

of

the camshaft bearings requires complete

disassembly of the engine. Use a press or a suitable

C

driver to remove bearings. distortion and to avoid damaging the bearing bore

Support casting to avoid

during removal and installation.

aging the bearing bore during removal and installation. Before installing main bearings, expand bearing bore by

placing the casting in an oven heated to 200°F practical, cool the precision bearing to shrink

(94OC).

it.

If

Before installing the front main bearing, usethe towelette included with the bearing kit to clean the outside of the bearing and bearing bore in the block.

Breathing

prolonged confacf with

vapor

from

fowelefte

skin

and

can be

harmful. Use only in well ventilated area and avoid

with

prolonged contact

skin.

10-13

After allowing three to four minutes for drying, apply the

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Locktitefrom the small tube to the mating surfaces bearing and the bearing bore. Align the oil holes in the bearing with the oil holes in the bearing bore (Figure 22). The oil passage should be at least half open. Install the bearing flush with the block, using the combination driver. Wipe bearing. Allow at least one hour for hardening at room

temperatu re.

off

any exesss Locktite around the

REAR BEARING END PLATE

of

the

In the rear bearing plate, install the bearing flush to

1

/64

inch

(0.40

mm) below the end of the bore. Be sure to align the the bearing bore(Figure 21). The oil passage must be at least half open. Lubricate bearing after installation.

If

head of lock pin is damaged, use side cutters or Easy

tool

Out

thrust washers must face the cranksahft, and washers

must be flat (not bent). The two notches on each washer must fit over the two lock pins

crankshaft (Figure 21).

oil

holes in the bearing with the oil holes in

to

remove and install new pin. Oil grooves in

to

prevent riding on the

ALIGN BEARING

WITH OIL HOLES IN

BEARING BORE

FIGURE

Engines shipped from the factory have separate thrust washers and main bearings for both front and rear of engine. Front bearing replacement part is a one piece bearing (with attached thrust washer) as shown in

Figure 22. front bearing.

21.

BEARINGS

Do

not add an additional thrust washer

FOR

REAR BEARING PLATE

BEARING BORE

OIL

THRUST

WASHER

FRONT MAIN

HOLES

to

this

Lubricate the front main bearing lightly with oil and insert the crankshaft. With the rear bearing plate gasket in place and the rear plate bearing lubricated, slide the

thrust washer (grooves toward crankshaft) and plate

overtheendofthecrankshaft. Line up notches ofthrust washer with lock pins before tightening end plate or lock pins will be damaged.

CRANKSHAFT

After the rear bearing end plate has been tightened, using the torque recommended in

AND SPECIAL

shown in Figure 23.

DlMENSlONS AND CLEARANCES

maximum endplay), remove the rear bearing end plate and add a shim (Figure and plate. Reinstall the end plate, making sure the thrust washer and shim notches line up with the lock pins. Torque and recheck endplay

TOOLS,

check the crankshaft endplayas

If

there is

ENDPLAY

ASSEMBLY TORQUES

too

much endplay (see

for minimum and

21)

between the thrust washer

of

the crankshaft.

FIGURE

22.

FRONT

1

FRONT MAIN

BEARING INSTALLATION

IENT

BEARING

10-14

MEASURE ENDPLAY HERE

(REFER TO DIMENSIONS

AND CLEARANCES)

FIGURE

23.

CRANKSHAFT ENDPLAY

1

Checking Bearing Clearance

Redistribution or publication of this document, 

by any means, is strictly prohibited.

The

most

clearance is shaft

is

installed in engine, bearing clearance may be

accurate

by

means

using micrometers. However,

With

of

determining

Plastigauge

bearing

if

crank-

measured by using a plastic strip (Plastigauge) manu-

factured for this purpose.

1, Make certain that all parts are marked or identified

so

that they are reinstalled in their original positions. using aclean dry cloth, thoroughly clean all oil from crankshaft journal and connecting rod.

2.

Place a piece bearing cap the full width

1

about

3.

Rotatethe crankshaft about30 degreesfrom bottom

/4 inch

of

correct size Plastigauge in the

of

the journal surfaceand

(6.35

rnrn)

off

center (Figure 24).

dead center and reinstall the bearing cap; tighten rod bolts

TORQUES

the torque specified in

AND

SPEClAL

TOOLS.

ASSEMBLY

Do

not turn the

to

crankshaft.

FIGURE

24.

MEASURING BEARING CLEARANCE

OIL

SEALS

4. Remove bearing cap.Theflauened Plastigaugewill

to

be found adhering

either the bearing cap or

crankshaft.

5-

Compare flattened

Plastigaugewiththegraduations

on Plastigauge envelope to determine clearance.

The number within the matching graduation on the envelope indicates total clearance in millirnetres or thousandths of an inch.

MOUNTING FACE

/

OF

GEAR COVER

FRONT

,645

INCH

THIS GEAR COVER SURFACL SHOULD BE CLEANED OF ALL OLD SEALING COMPOUND BEFORE INSTALLING SEAL.

The bearing plate must be removed

to

replace the oil

seal (Figure 25). Drive the oil seal out from the inside. Before installing seals, fill thespace between lips with a

multi-purpose grease. This will impiove sealing. When installing the gear cover oil seal, tap the seal

inward until it is .645 inch

6.4 mm) from the front

of

the

(1

gear cover.

When installing the bearing plate oil seal, tap the seal

into the bearing plate bore

plate

shoulder in the

bore. Use a seal expander

to

bottom against the

or

place

a piece of heavy paperaround theend of thecrankshaft,

to

when replacing the bearing plate seal. Remove the paper as soon

REAR BEARING PLATE

1

avoid damaging the

as

the plate is in place.

THIS SURFACE SHOULD BE

CLEANED OF ALL SEALING COMPOUND BEFORE INSTALLING SEAL

DRIVE

OR

SEAL TO SHOULDER OF THE PLATE BORE

PRESS

OLD

OIL

u

GEAR COVER

OIL

FIGURE

SEAL

25.

GEAR COVER AND REAR BEARING PLATE

10-15

REAR

OIL

REARING

OIL

SEAL

SEALS

PLATE

LS-1163

PISTON

Redistribution or publication of this document, 

by any means, is strictly prohibited.

ASSEMBLY

Lubricate all parts with engine oil. Position piston on its respective rod and install the

pin.

Install the rings on the pistons starting with the oil

26).

Use

control ring (Figure

to

prevent twisting or excessive expansion of the

a piston ring spreader

ring. Compression rings have a dot or the word “top” on one side of the ring to indicate which side faces the top

of

the piston. Unmarked piston rings

can be installed either way. The oil control ring has

an expander; install the expander first and then

close until the expander ends butt. The joint should

180

be

degrees from the gap

of

that ring.

FIGURE

INSTALLATION

1.

Turn the crankshaft to position the number one rod bearing journal

2.

Lubricate the number one piston assembly and inside

of

the cylinder. Compress the rings with a ring

OF

at

compressor (Figure

3.

Position the piston and rod assembly in the cylinder block. Notched side

camshaft. Rod bolts must be off-set toward outside

of

block.

Tap the piston down into the bore with the handle

4.

end of a hammer until the connecting rod is seated on the journal (Figure the rod. Install one fastener and tighten to

(7

Nm).

Repeat this for the other fastener. Tighten

both fasteners down to

26.

PISTON

the bottom

RINGS

IN CYLINDER

of

its

stroke.

27).

of

connecting rod must face

27).

Install the bearing cap on

14

ft-lbs

(1

9

Nm).

5

ft-lbs

CT-1047

10-1

6

FIGURE

27.

INSTALLING PISTON

CONNECTING

AND

ROD

Install the remaining piston and rod in the same manner. Crank the engine over by hand to see that all bearings are free.

5.

Install the oil base with a new gasket.

6.

Install the cylinder heads. See Cylinder Headsection

for torques and torquing procedure.

7.

Replace

oil

and break in engine.

t

P

5.

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Follow the head torque sequence shown Figure

28.

Graphoil head gasket torque procedure:

A.

Tightenall boltsto5 ft-lbs(7 Nm),then

(1

4

Nm), then

BLY TORQUES.

to

the torque specified in

Recheck all head bolts for

correct torque. Asbestos head gasket torque procedure:

B.

Tighten all boltsto

5

ft-lbs

(7

Nm), then

(1 4 Nm), then to the torque specified in

BLY TORQUES.

Recheck all head

correct torque.

Remove

the cylinder heads for lead cleaning and gasket

change at least

CYLINDER

every

200

HEADS

hours,

or

when

poor engine performance is noticed. For engines running on unleaded fuel this interval may be extended to

6

400

hours.

1. Use a 112 inch (13 mm) socket wrench to remove cylinder head

4

j

ACAUT'oN

137"

C])

to

cool

bolts.

Lift

heads

off.

Torquing or removing cylinder

heads when hot (above

700°F

will result in head damage. Allow heads to

below

100°F

(37°C)

before

torquing

or

removing.

2.

After removing heads, clean out all carbon deposits.

in

10

ft-lbs

ASSEM-

10

ft-lbs

ASSEM-

bolts

for

Be careful not to damage the outer sealing edges where gasketsfit.The headsare made ofaluminum and can be damaged by careless handling.

ALIGNING BLOWER WHEEL,

VENTURI

AND CHAFF SCREEN

Use new head gaskets and clean both the heads

3.

and the cylinder block thoroughly where the head gaskets rest.

4.

Place a head gasket on the cylinder blockand align the holes in the gasket with the holes in thecylinder block. While holding the gasket against the cylinder head, carefully install the cylinder head on the

Do

engine.

not attempt to slide the head bolts through thegasket without thecylinder block behind it or the gasket may tear.

It

may be difficult to line up the screw holes in the blower housing chaff screen with those in theventuri and those in the blower wheel if these parts are separated without noting their relative positions. The holes will match

up

the parts are aligned as shown in Figure 29.

if

NO.

1

CYLINDER

FIGURE

28.

CYLINDER HEAD TORQUE SEQUENCE

NO. 2 CYLINDER

c-1002

10-1

7

FIGURE

29.

BLOWER WHEEL, VENTURI AND CHAFF SCREEN ALIGNMENT

cs-1WI

CYLINDER

Redistribution or publication of this document, 

by any means, is strictly prohibited.

On

B48G

AIR

HOUSING

beginning Spec

CLEARANCE

Dl

B43G7

and

B43E

engines the cylinder air housing to cylinder head cooling fin clearance must be checked during assembly.

is

0.187

to

0.313

inch

(4.76

The correct clearance

7.94

mm).

to

To

adjust cylinder air housing clearance, loosen

A

capscrews

piece of

0.250

and B (Figure

inch

[6.35

30).

Insert spacer tool, (a

mrn]

thick bar stock will work) between the cylinder head cooling fins and cylinder air housing

capscrews

at

the

(A

points

and

illustrated

6)

and

in

Figure

the spacer

30.

tool.

Tighten

b

FIGURE

30.

CYLINDER

AIR

10-1

8

HOUSING

CLEARANCE

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by any means, is strictly prohibited.

Cummins

Redistribution or publication of this document, 

by any means, is strictly prohibited.

Power

1400 73rd Avenue Minneapolis,

MN

763-574-5000

Fax:

763-574-8087

Generation

N.E.

55432

Cummlns and Onan

are

registered trademarks

of

Cummins

Inc.