Toro 74021, 74041, 74101, 74120, Y1-16OE01 Service Manual

ONAN TORO POWER PLUS P216V, 18V, 20V ENGINE - VERTICAL

Table of Contents – Page 1 of 2

SAFETY PRECAUT I O NS

GENERAL PROTECT AGAINST MOVING PARTS BATTERIES FUEL SYSTEM EXHAUST SYSTEM EXHAUST GAS IS DEADLY! COOLING SYSTEM KEEP THE UNIT AND SURROUNDING AREA CLEAN

CAUTION

GENERAL INFORMATION INTRODUCTION ENGINE MODEL REFERENCE

SPECIFICATIONS DIMENSIONS AND CLEARANCES ASSEMBLY TORQUES SPECIAL TOOLS ENGINE TROUBLESHOOTING

OIL SYSTEM CRANKCASE OIL OIL FILTER CHANGE CRANKCASE BREAT HER PRESSURE LUBRICAT IO N OIL PUMP OIL BYPASS CHECK BALL

FUEL SYSTEM CARBURETOR CARBURETOR SPEED SETTINGS CARBURETOR OVERHAUL REMOVAL DISASSEMBLY CLEANING AND REPAIR REASSEMBLY AN D INSTALLATION PULSATING-DIAPHRAGM FUEL PUMP FUEL PUMP TEST PROCEDURE AIR CLEANER GOVERNOR SENSITIVIT Y

ONAN TORO POWER PLUS P216V, 18V, 20V ENGINE - VERTICAL

Table of Contents – Page 2 of 2

IGNITION AND BATTERY CHARGING IGNITION SYSTEM DESCRIPTION IGNITION TIMING CONTINUITY TEST IGNITION COIL SPARK PLUGS BATTERY INSPECTION BATTERY JUMP STARTING FLYWHEEL ALTERNAT OR ALTERNATOR OUTPUT TEST

STARTING SYSTEM ELECTRIC STARTER SERVICE STARTER REMOVAL STARTER DISASSEMBLY STARTER ASSEMBLY INSPECTION AND TESTING STARTER MOUNTING

ENGINE DISASSEMBLY DISASSEMBLY/ASSEMBLY VALVE SYSTEM TAPPETS VALVE FACE AND SEAT GRINDING FLYWHEEL GEAR COVER GOVERNOR CUP TIMING GEARS PISTONS AND CONNECTING RODS CYLINDER BLOCK CRANKSHAFT BEARINGS CRANKSHAFT ENDPLAY CHECKING CONNECTING ROD BEARING CLEARANCE OIL SEALS PISTON ASSEMBLY INSTALLATION OF PISTON IN CYLINDER CYLINDER HEADS

Service

Manual

P216V,18V,2OV

Toro

Power

Plus

Engine

Tractors

1710

& Riding Mowers

Safety

It

is recommended that you read your engine manual and become thoroughly acquainted with your equipment before you start the engine.

severe personal injury or death.

Precautions

This symbol

diate hazards which will result in

This symbol refers

unsafe practice which can result In

if

used warns of imme-

lo

a hazard or

Fuel System

DO NOT DO NOT smoke or use an open flame

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.. flexible lines as copper will work harden and become brittle enough to break.

fill

fuel tanks while engine is running.

in

Do

not use copper piping for

the vicinity

of

the

This symbol refers

personal injury or product or properly damage.

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.

Use

of

this engine in aircraft can result in engine failure

and causes serious personal injury or death.

General

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

Make sure that all fasteners on the engine are secure and accurately torqued. Keep guards in position over fans, driving belts, etc.

If

it is necessary to make adjustments while the engine is running, use extreme caution when close to hot exhausts, moving parts. etc.

Protect Against Moving Parts

Do

not wear loose clothing in the vicinity such as PTO shafts, flywheels, blowers, couplings, fans, belts, etc.

unsafe practice which

This engine Is not designed or in-

tended for use in any type of aircraft.

lo

a hazard or

can result in

of

moving parts,

Be sure all fuel supplies have a positive shutoff valve.

Exhaust System

Exhaust products toxic and can cause injury, applications, especially those within should be equipped with an exhaust system to discharge gases to the outside atmosphere.

Do

not use exhaust gases to heat a compartment

Make sure that

Ensure that exhaust manifolds are secure and are not

warped by bolts unevenly torqued.

Gas

Exhaust Exhaust gases contain carbon monoxide, a poisonous gas

that can cause unconsciousness and death. and colorless gas formed during combustion fuels. Symptoms

Dizziness Headache

Weakness and Sleepiness

If

you experience any immediately, shut down the unit and do not use until it has been inspected.

The best protection against carbon monoxide inhalation proper installation and regular, frequent inspections complete exhaust system. or appearance immediately and have it inspected and repaired at once by a competent mechanic.

is

of

any internal combustion engine are

or

death if inhaled.

a

confined area,

your

exhaust system

Deadly!

of

carbon monoxide poisoning are:

Vomiting

Muscular Twitching

Throbbing in Temples

of

these symptoms, get out into fresh air

If

of

you notice a change in the sound

exhaust system, shut the unit down

is

free

It

is an odorless

of

hydrocarbon

All

of

engine

leaks.

is

of

the

Keep your hands away from moving parts.

Batteries

Before starting work on the engine, disconnect batteries

of

to prevent inadvertent starting DO NOT SMOKE while servicing batteries. Lead acid

batteries give can be ignited by flame, electrical arcing or by smoking.

Verify battery polarity before connecting battery cables. Connect negative cable last.

off

a highly explosive hydrogen gas which

the engine.

Cooling System

Coolants under pressure have a higher boiling Point than water. coolant temperature is above engine

Keep the Unit and Surrounding Area Clean

Make sure that oily rags are not left 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.

DO

NOT open a radiator pressure cap when

212°F

is

running.

(l00°C)

or while

E-6

Table

of

Contents

TITLE

General Information Specifications Dimensions and Clearances Assembly Torques and Special Tools Engine Troubleshooting Oil System

Fuel

System. Ignition and Battery Charging Engine Wiring Diagram. Starting System.. Engine Disassembly

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PAGE

. l-1 .2-1

.3-1

.4-1

.5-1 .6-1 .7-1 .8-1 .8-7

.9-1

10-1

I

EXHAUST GAS

Exhaust gases from all fuels (including diesel, gasoline, liquid propane, 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:

Dizziness Throbbing in Temples Nausea Muscular Twitching Headache Vomiting

Weakness and Sleepiness Inability

IF

YOU

OR

ANYONE ELSE EXPERIENCE ANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. attention. Shut down the unit and do not operate until it has been inspected and repaired.

Protection against carbon monoxide inhalation includes proper installation,

ventilation and regular, frequent visual and audible inspections of the complete

exhaust system.

IS

DEADLY!

to

Think Coherently

If

symptoms persist, seek medical

I

General

Information

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 MANUAL for 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

cleaner side of the engine is the front end. Right and left sides are determined by viewing the engine from the

front. The No.

on the left.

If

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

Use the table separate engine system sections.

The troubleshooting guide is provided

reference for locating and correcting engine trouble. The wiring diagram

nents are interconnected. The disassembly section contains major overhaul

procedures for step by step removal, disassembly, inspection, repair, and assembly components.

to

the engines listed on the cover. The air

1

cylinder is on the right,

of

contents for a quick reference

shows

how the electrical compo-

No.

2

cylinder is

or

supervise and

to

the job

as

of

the engine

a quick

to

the

Use only Genuine ensure quality and the best possible repair and overhaul results. When ordering parts, always use the complete model and spec number as well shown on the nameplate.

ENGINE

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

How

to

interpret MODEL and SPEC NO.

P

2 16

12

1.

Factory code for general identification of basic

engine series.

2.

Number of cylinders.

3.

BHP rating.

4.

Designation

5.

Engine duty cycle.

6.

Factory code for designated optional equipment,

any.

7.

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

Tom

Plower Plus replacement parts to

MODEL

V

3

(G

=

horizontal shaft,

as

the serial number

REFERENCE

to

'the model and

to

your engine.

/

10464

6

V

=

vertical shaft)

A

7

if

INCORRECT SERVICE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE PERSONNEL

MUST

SERVICE.

BE

QUALIFIED TO PERFORM ELECTRICAL AND/OR MECHANICAL

OR

REPLACEMENTOF PARTS CAN RESULT IN SEVERE

Specifications

.

This manual contains

SPECIFICATION MEASURE P216V P218V P220V

Number Bore

Stroke

Displacement

Compression Ratio

Power at

Oil Capacity Qts

Valve Clearance (Cold)

of

Cylinders

Rated Speed

Without Filter (litre) Oil Filter Capacity

Intake in

(3600

rpm)

.

SI

metric equivalents that

U.S.

after the

UNIT OF SERIES

customary units

follow

of

measure.

immediately in parentheses

2

in

(mm)

in (mm) CU in

(cm³)

BHP

(kW)

3.250 3.250 3.250

(82.55) (82.55) (82.55)

2.625

(66.68)

43.3

(71

0)

6.5

to

1

16 18 20

(1 1.9) (1 3.4)

(73.03) (73.03)

7.0

1.7 1.7. 1.7

(1 .6)

Qts

(litre)

.3 .3 .3

(.3) (.3) (.3)

.005

2

2.875 2.875

47.7 47.7

(782)

to

1

(1

(782)

7.0

(1

4.9)

(1.6)

to

__-

.005 .005

1

Spark Plug Gap

Ignition Timing Cylinder Compression psi

in

(mm)

BTC

(kPa)

.025 (.64) (.64) (.64)

20°

75

(517

to

115 75

793) 51

.025 .025

20° 20

to

7

115

to

793) (517

75

to

115

793)

2-

1

Dimensions

All

measurements given at room temperature

millimeter measurements in parentheses

and

of

.

Measurements are

Clearances

70°F (21 °C)

.

All

measurements are given in inches with approximate

for

standard size parts

.

DESCRIPTION

CYLINDER BLOCK

Cylinder Bore Diameter Piston Clearance Maximum Allowable

Taper

Out-of-Round Top Main Bearing Bore Top Main Bearing Inside Diameter (bearing installed)

Top Main Bearing Clearance Bottom Main Bearing Bore Bottom Main Bearings Inside

Bottom Main Bearing Clearance Cam Bearing Bore Cam Bearing Inside Diameter (bearing installed) Cam Bearing Clearance

Intake Valve Seat Bore

Exhaust Valve Seat Bore Tappet Bore Diameter Tappet Clearance

CRANKSHAFT

Top Main Bearing

Bottom Main Bearing

Connecting Rod Journal Diameter

End Play

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

Diameter (bearings installed)

Journal Diameter Journal Diameter

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

........

3.2490

0.0033

2.1 870

2.001

0.0024

2.1 840

1.9990

0.001

1.4995

1.3757

0.001

1.4395

1.1

890

0.7500

0.0020

1.9992 (50.78)

1.9972

1.6252

0.0060

5

0

5

(82.52) (0.084)

(55.55)

(50.84) (0.061) (55.47)

(50.77) (0.025) (38.08) (34.94) (0.038) (36.56)

(30.20) (1 9.05) (0.051

)

(50.73)

(41.28)

(0.1

52)

MAXIMUM

Inches

3.2500

0.0053

0.005

0.003

2.1 880

2.0040

0.0042

2.1 850

2.0020

0.0048 1

5005

1.3787

0.0030

1.4405

1.1 900

0.751 5

0.0040

2.0000

1.9980

1.6260

0.01 20

(mm)

(82.55)

(0.1

35)

(0.1

3)

(0.08)

(55.58)

(50.90)

(0.1

07)

(55.50)

(50.85)

(0.1

22)

(38.1

1)

(35.02) (0.076) (36.59) (30.23)

(1

9.09)

(0.1 02)

(50.80)

(50.75)

(41.30) (0.305)

CONNECTING

Large Bore Inside Diameter (rod bolts torqued) Large Bore Clearance Piston Pin Bore Piston Pin Clearance End Play

CAMSHAFT

Journal Diameter

Lobe Height

P216V. P218V Intake P216V. P218V Exhaust P220V Intake P220V Exhaust

End

Play

ROD

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

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

3-

1

1.6280

0.0020

0.6879

0.0002

0.0020

1.3740 (34.90)

0.01

10

(41.35)

(0.051)

(1

7.47)

(0.005)

(0.051)

(0.279)

1.6285

0.0033

0.6882

0.0007

0.0320

1.3745 (34.91)

1.1 370 (28.88)

1.1 570 (29.39)

1.1

670 (29.64)

1.1

570 (29.39)

0.0480 (1.219)

(41.36) (0.084)

(1

7.48) (0.01 8) (0.81

3)

DESCRIPTION

(standard size)

Measure 90° from

1

.187

below

top

Ring Groove Width

Top Groove Middle Groove. Bottom Groove.

Top Groove Clearance.

Pin Bore Pin Clearance

PISTON PIN

Diameter

PISTON RINGS

End Gap

INTAKE VALVE

Stem Diameter Face Angle

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

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

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

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

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

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

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

bore

of

piston.

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

.......

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

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

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

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

...........

MINIMUM

Inches

3.2445

0.0800.

0.0800

0.1 880

0.0030

0.6877

0.00004

0.6875 (1 7.46) 0.6877 (1 7.47)

0.01

00

0.2795 (7.099) 0.2800 (7.1 12)

(mm)

(82.41) (2.032)

(2.032) (4.775) (0.076) (1 7.47) (0.001)

(0.254) 0.0200 (0.508)

44

.

MAXIMUM

Inches

3.2462 (82.45)

0

0.081

.0.0810 .0.1890

0.0080

0.6882

0.00064

(mm)

(2.057) (2.057) (4.800) (0.203) (1 7.48) (0.01 6)

INTAKE VALVE SEAT

Outside Diameter Seat Width Seat Angle

Stem Diameter Face Angle

EXHAUST VALVE SEAT

Outside Diameter Seat Width Seat Angle

VALVE GUIDE

Intake Inside Diameter Intake Stem to Guide Clearance Exhaust Inside Diameter Exhaust Stem to Guide Clearance..

TAPPET

Body Diameter.

VALVE SPRINGS

Free Length (approximate) Valve Open Length Valve Closed Length Spring Load (valve open length) Spring Load (valve closed length)

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

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

VALVE

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

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

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

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

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

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

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

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

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

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

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

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

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

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

1.4700 (37.34) 1.471

0.031

0.2780 (7.061) 0.2785 (7.074)

1.1 920

0.031

0.281

0.001

0.2805

0.0020

0.7475 (1 8.99) 0.7480

0

0 0

(0.787) 0.0470 (1.1 94)

(30.28) (0.787)

(7.1 37) (0.025) (7.1 25) (0.051)

1.600

1.055

1.346

55

Ib.

25

45°

44

45°

-

1.1 930

0.0470

0.2820

0.0025

0.281

0.0035

(40.64) (26.80) (34.1 9) (25 kg) (11

kg)

0

5

(37.36)

(30.30) (1.194)

(7.1 63) (0.064) (7.1

50)

(0.089)

(1 9.00)

GEAR BACKLASH

Timing Gear Oil Pump Gear..

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

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

3-2

0.001

0 0

(0.025)

0.0050

0.0080

(0.1 27) (0.203)

Assembly

The torque values given in Table 1 have been deter- Tighten all studs, nuts, and capscrews as required to mined for specific applications. Standard torque values keep them from working loose. Refer to the must not be used where those listed in Table 1 apply. The engine assembly torques given here will assure proper tightness without danger threads must be clean and lubricated with new engine oil before torquing.

Torques

of

stripping threads.

All

MANUAL

for

the location of washers and capscrews.

PARTS

DESCRIPTION

Gearcase Cover Oil Base Oil Base Cover (inner bolts). Oil Base Cover (outer bolts). Oil Cooler Oil Pump

Hood Support Screws..

Starter Mounting Bolts

Connecting Rod Bolts.. Flywheel Capscrews

Valve Cover.

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

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

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

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

........

.........

........

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

.......

.

..........

....

TABLE

TORQUE SPECIFICATION Ft.-Lb. Nm

10-12 14-16

27-29 36-39

19-21 25-28

9-11 12-15

20-24

7-9 10-12

7-9 19-21 25-28 12-14

50-55

3-4 4-5

27-33 10-12

16-19

67-75

1.

DESCRIPTION

Cylinder Head Bolts (cold)

Asbestos Gasket Graphoil Gasket..

Intake Manifold

Mounting Screws..

Exhaust Manifold

Mounting Screws..

/4"

Other 1

Nuts and Bolts

Other 5/16" Cylinder Block

Nuts and Bolts

Cylinder Block

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

...........

..........

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

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

TORQUE

SPECIFICATION

Ft.-Lb. Nm

16-1 8 14-1 6

6-10 9-11

7-9

8-10

22-24 19-22

8-14 12-15 10-12 11-14

Special

The following is a partial list of the special from Onan. Use Onan tools whenever a repair or overhaul is required. Refer to the complete listing of tools available.

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

TOOL CATALOG

available

for a

Engine

Troubleshooting

5-

M-1686

1

Oil

System

CRANKCASE

Refer

to

Periodic Maintenance Schedule (located in the Operator's Manual) for oil change interval. in extremely'-dusty, high ambient, 'or low ambient conditions, change oil more often.

Hotcrankcase oil can cause burns if

it comes in contact with skin.. Wear

protective clothing and keep fingers and hands clear

when draining oil.

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

atures, and oil foaming.

Run engine until thoroughly warm before draining oil. Stop the engine, place a pan 'under the drain outlet and remove the drained, clean and replace the drain plug. Fill crankcase with correct amount of oil. Refer crankcase capacity. Use oils meeting the fication SF, SF/CC, or SF/CD. Refer the proper viscosity grade of oil

oils are recommended for severe duty use and at

temperatures above 32°F

consumption.

oil

drain plug. After the

Do

OIL

If

operating

not overfill crankcase.

oil

is

completely

to

SPEClFlCATlONS for

API

classi-

to

chart

to

determine

to

use. Straight weight

(0°C)

for minimum oil

Crankcase pressure can blow out hot oil, which can cause severe personal

Do

injury.

Oil level should be to the FULL mark of the dipstick. Start engine and run for a short time around the drain plug.

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

not check oil while the engine

to

ENGINE

to

OIL

TEMPERATURE-

OIL

FILTER

Periodic Maintenenace Schedule (located in the

VISCOSITY

CHANGE

is

running.

check for oil leaks

CHART

If

FIGURE

1.

CRANKCASE

OIL

FILL

C-1000

Spin

off

oil

filter elementand discard it. Thoroughly clean filter mounting surface and make sure new gasket is inserted gasket. Spin element down by hand until gasket just touches mounting pad and then turn down an additional

112-314

With oil in crankcase, start engine and check for leaks around filter element. Retighten only as much as

necessary

in

the element. Apply a thin film of clean oil to the

turn. Do not overtighten.

to

eliminate leaks; do not overtighten.

CRANKCASEBREATHER

The crankcase breather prevents pressure from building

It

up the crankcase by removing moisture or gasoline vapors and other

harmful blow-by materials from the crankcase. These vapors are routed mixed with incoming air and burned in the combustion chamber. high oil consumption, rough idle, reduced engine power, and engine.

A

sticky breather valve can cause oil leaks,

a

rapid formation of sludge and varnish within the

Crankcase Breather Service

The crankcase breather does not require servicing.

Replace breather if it’s broken or cracked or becomes pressurized as evidenced by seals or excessive oil

also prevents oil contamination

to

the carburetor where they are

if

crankcase

oil

leaks at the

in

the air cleaner housing.

Oil

Bypass

The oil bypass check ball is located in the gain access removed. The check ball limits oil pressure mum temperatures

The check ball is non-adjustable and normally does not

need maintenance. Determine

correctly by inspecting as follows (Figure

1.

Remove internal retaining ring.

2.

Remove spring and check ball with a magnetic

3.

Determine proper operation by checking the spring and check ball according ments:

of

Check

to

about

Ball

the check ball the oil base cover must be

25

psi

(172

kPa) at normal operating

(250°F

oil temperature).

if

check ball is operating

to

the following measure-

2):

oil

to

base.

a maxi-

tool.

To

PRESSURE

All

engines use an oil pump

to

the engine parts. The oil supply collects in the oil

oil base where

A

bypass valve is used before removing oil base and always use a new gasket when replacing the oil base.

Oil

Pump

The oil pump is mounted below the gear cover and is driven by the crankshaft gear. pump cover registers with a drilled passage crankcase. Parallel passages distribute oil and bottom main bearing and the oil bypass valve.

Circumferential grooves in the main bearings supply oil

to

connecting rod bearings through drilled passages from each main journal. front main bearing oil supply

bearing; rear cam bearing is splash lubricated. Normal oil pressure should be

1500

temperature.

value, inspect oil system for faulty components.

it

is picked up by the oil pump pick-up cup.

rpm when the engine is at normal operating

If

pressure at

LUBRICATION

to

provide a constant flow of

to

control oil pressure. Drain oil

A

discharge passage in

to

the top

A

drilled passage connects the

to

the front camshaft

8

psi

(55

kPa) or higher at

1500

rpm drops below this

in

the

Check Ball Diameter. Spring

Free Length Load..

4.

Check the check ball seat and clean away- any accumulation of metal particles which could cause erratic check ball action. Verify the check ball seat is

not damaged.

5.

Clean spring and check ball in parts cleaning

solvent and install.

6.

A

new internal retaining ring must be installed with the outside edges turned towards the top. Press in until retaining ring outside edge is

(3.3 ± .3

OIL

BASE

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

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

when compressed

mm) from top.

0.13±0.01” (33±.3mm)

.....

.0.3125

.2.6 ± 0.2

to

RETAINING RING

inch

1.00

inch

Ibs

(11.6

0.5

inch

0.13 ± 0.01

(7.94

(25.4

±

(12.7

mm)

0.9

mm)

inch

N)

Check oil pump thoroughly for worn parts and replace pump as an assembly parts (pickup cup, pickup tube, gaskets, etc.) can be replaced individually. Prime pump by oiling it before installing.

if

parts are worn. Other component

6-2

FIGURE

2.

OIL BYPASS

CHECK

LS-1102

BALL

F’uel

System

..

_.i

..

.

CARBURETOR

All

carburetors have a fixed’main jet. An’optional fixed main jet is avai1abI.e for altitude compensation above 5,000

feet.

The carburetor idle mixture was set for maximum efficiency at the factory and should normally not disfurbed.

If

adjustments seem necessary, first be sure the ignition system is working properly and governor sensitivity is properly adjusted.

The carburetor has a limited idle adjustment range

between stops of adjusted within these limits; in

fl/8

turn. The screw should only be

to

lean the mixtuie, out

richen.

Overtightening the mixture adjustment

screw

Turn mixture adjustment screw in

will

cause carburetor damage.

only

until light

tension can be felt.

If

replacing idle mixture screw, turn in until lightly

seated, then turn sciew back out 1-1

limiter cap with the plastic

stop

/4

turns. Replace

approximately centered.

be

to

Carburetor

1. Start the engine and allow it

Speed

Settings

to

warm up thoroughly

“(at least 10 minutes).

Someequipment manufacturers may require higher throttle stop speed and governor low speed rpm

settings. Refer to equipment manufacturer’s Operator’s Manual for .the correct rpm settings. When

.

rpm settings are not specified by

the

equipment

manufacturer, use the rpm settings listed in Steps

and

3.

2.

Move the engine speed control

to

the slow position. Adjust the low speed adjustment screw on the governor

so

the throttle stop screw on the carburetor controls engine speed. Adjust the throttle stop screw for

3.

Adjust the governor low speed stop for 11 idle.

4.

Move the engine speed control

1000

rpm idle (Figures 1 and

-..

_.

..

to

the fast position.

2).

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

.-

00

so

2

rpm

the

FIGURE

HIGH

SPEED

STOP

GOVERNOR

1.

GOVERNOR SPEED ADJUSTMENT

ASSEMBLY

FS-1000-1

LIMITER

CAP-

FIGURE

2.

CARBURETOR ADJUSTMENTS

FS-1406.2

CARBURETOR

Carburetion problems

that

OVERHAUL

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 carburetor overhaul.

In general, overhauling a carburetor consists

of

disassembly, a thorough cleaning, and replacement of worn parts. Carburetor overhaul kits 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 reassemb-

ling. Read through all the instructions before beginning

for a better understanding of the procedures involved.

Carburetor components are shown in Figure

lgnition of fuel can

result

personal injury or death.

3.

in severe

Do

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

Removal

1.

Remove air cleaner assembly.

2.

Disconnect throttle linkage, choke control, and fuel line from carburetor.

3.

Remove carburetor from intake manifold.

ASSEMBLY

IDLE

ADJUSTMENT

NEEDLE

Disassembly

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.

AND

LEVER

THROTTLE STOP CAP

SCREW

FIGURE

3.

CARBURETOR ASSEMBLY

FS-1440-4

NEEDLE

AND SEAT

FLOAT

BEND FLOAT

TANG HERE

TO ADJUST BEND FLOAT ARM

LEVEL

ADJUSTMENT WITH FUEL

HERE TO ADJUST

NO FUEL

When checking (loaf

FIGURE

level

4.

CARBURETOR FLOAT LEVEL ADJUSTMENTS

Cleaning and Repair

1.

Soak all metal components not replaced in carburetor cleaner. other non-metal parts. Follow the cleaner 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 which may increase the size of critical passages.

4.

Check the condition of the adjustment needle;

replace if damaged. Replace float

or

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.

Do

not soak non-metal floats

if

loaded with fuel

(35

and

or

PSI).

float

drop,

measure lo float

body,

not

seam.

Reassembly and Installation

1.

Install needle valve, main jet, and float assembly. Make sure float pivot pin moves freely without binding.

2.

Turn carburetor on its side and measure float level (Figure Measure float drop (the distance from the top of carburetor body 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.

Connect governor and throttle linkage, choke control, and fuel line. Mount air cleaner assembly.

7.

Adjust carburetor and governor according tions given in this section.

4).

Adjust float level only

is

properly placed and float

'if

necessary.

to

top of float). Adjust only if

to

direc-

PULSATING-DIAPHRAGM FUEL PUMP

Pulsating-diaphragm fuel pumps, or pulse pumps, rely on changes in crankcase vacuum movement of the pump diaphragm. As the engine's pistons move outward, a vacuum is created. This vacuum is transmitted to pull back and suck fuel into the pump. pistons move inward, crankcase vacuum is' reduced and the diaphragm return spring pushes the pump diaphragm forward, forcing fuel through the pump outlet.

to

the pump diaphragm causing it

to

create a pulsating

As

the engine's

Ignition fuel can result severe personal injury or death.

Thoroughly clean up

7.

Remove fuel outlet line from fuel pump.

8.

Connect a pressure gauge

a

piece of fuel hose with clamps.

9.

Start engine and allow seconds. While holding pressure gauge level with pump outlet record pressure gauge reading.

any

spilled fuel.

to

fuel pump outlet using

idle for at least five

in

Fuel Pump Test Procedure

Before testing, make certain the fuel pump vacuum and

fuel 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.

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

Thoroughly clean up any spilled fuel.

2.

Shut engine off and remove fuel inlet line from fuel pump.

Connect a vacuum gauge to fuel pump inlet using a

3.

piece of fuel hose with clamps. Start engine and allow

4.

seconds. Record vacuum gauge reading. Move throttle control

5.

least five seconds and record vacuum gauge reading.

Shut engine off and remove vacuum gauge hose

6.

from fuel pump inlet. Connect fuel inlet line pump.

to

idle for at least five

to

high idle position. Wait at

to

fuel

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

11.

Shut engine

from fuel pump outlet. Connect fuel outlet line

pump.

Replace the fuel pump

values specified in TABLE 1.

off

and remove pressure gauge hose

if

test readings are not within the

TABLE

1

to

fuel

PULSE PUMP TEST SPEClFICATlONS

ENGINE PUMP INLET PUMP OUTLET

SPEED VACUUM PRESSURE

(Minimum) (Minimum)

Low

Idle

High ldle

2.6

inches 1.7 psi

of mercury

2.6

inches 1.7 psi

of mercury

7-4

AIR

CLEANER

A

dirty air cleaner element can cause

engine damage. Ensure air cleaner

element is kept clean and free

Running engine without air cleaner element will result in engine dam-

age.

Do

not run engine without air cleaner element

installed.

of

excess debris.

Engine is equipped with a paper element. Refer

to

Periodic Maintenance Schedule (located in the Opera-

tor's Manual) for service and replacement intervals.

Service by gently tapping element on a flat surface. engine is equipped with an element wrapper, refer

to

Periodic Maintenance Schedule for service intervals. Service element wrapper as follows:

1.

Wash element wrapper in water and detergent (Figure a sponge. Allow wrapper

2.

Distribute one tablespoon

5).

Remove excess water by squeezing like

to

dry thoroughly.

of

SAE

30

'engine

oil

evenly around wrapper. Knead into wrapper and wring out excess oil.

If

ELEMENT

COVER

ELEMENT

BASE

FIGURE

5.

CLEANING ELEMENT WRAPPER

7-5

FIGURE

6.

AIR

CLEANER ASSEMBLY

XFS-1773

GOVERNOR

These engines are adapted of speed settings between minimum and maximum by moving the throttle lever until the desired speed is reached.

Check Governor arm, spring, linkage, and throttle shaft for a binding condition or excessive wear at connecting points. act slowly and regulation to be poor. Excessive wear will cause a hunting condition and regulation to-be erratic. Work the governor arm back and forth several times by hand while the engine is idling to check for above conditions.

A

binding condition will cause the governor to

is

desired. Engine speed

SENSITIVITY

for use

where a wide range

is

controlled

The governor linkage should be set (Figure

1.

2.

If

settings. Adjust

7):

The governor spring should be placed in the second

hole from the end in the governor control arm. The governor spring should be placed in the third hole away from pivot in the governor arm. Moving spring away from pivot will decrease sensitivity, moving the spring closer will increase sensitivity

The governor control rod

middle hole of the governor arm.

adjustments were made, recheck the carburetor rpm

if

necessary.

should

up

as

follows

be placed in the

FIGURE

7.

GOVERNOR

7-6

FS-1791

LINKAGE

Ignition and Battery Charging

IGNITION SYSTEM DESCRIPTION

This engine is equipped 'with 'an electronic battery ignition system. Both spark plugs fire, simultaneously, thus the need for a distributor is eliminated. The electronic ignition module is located on the engine gear cover below the flywheel. The module receives a timing signal from magnets within the trigger ring which rotates with the engine crankshaft (Figure ignition is suspected of malfunctioning, proceed as follows:

TRIGGER

RING

IGNITION MODULE

FIGURE

1.

Check all electrical connections to be sure they are clean and tight. wiring is intact, go

2.

Refer proper resistance. step

trical shock. or wires while ignition is on.

1.

IGNITION MODULE AND TRIGGER RING

If

all connections are good and

to

step

to

IGNITION COIL section to test coil for

If

coil checks out good, go

3.

The electronic ignition produces current which can cause elec-

Do

not touch electrical components

2.

1).

If

the electronic.

\

ES-1670

to

Accidental starting of the engine

can result in severe personal injury or death. Remove spark plugs before proceeding.

Ignition of cylinder gases can

cause severe personal injury.

Ground spark tester away from spark plug hole.

3.

Pull spark plug wires

off

spark plugs and remove spark plugs. Connect an approved spark tester to each of the spark plug wires and ground them away

from spark plug hole. Turn key on and crank engine

over for

5

seconds while watching for spark.

If spark occurs regularly, the problem is not in the ignition system.

attach any lead or jumper with power (such as

to

coil negative terminal.

4.

Connect a jumper lead directly from the positive battery terminal to the positive

If

no spark occurs, go to step

Incorrect wiring can cause elec-

tronic ignition damage.

Do

4.

not

B+)

(+)

coil terminal (smaller diameter of the two threaded posts). Crank engine over while watching for spark.

If

spark

occurs, the problem is in the low oil pressure cut out

switch (if equipped) or related wiring, the lubricating system (low oil pressure), or in the other circuitry bringing voltage to the coil.

,.step

5.

Connect positive side of voltmeter to negative

If

no spark occurs, go to

coil terminal (larger diameter of the two threaded posts) and negative side of voltmeter to engine ground. Turn key on and rotate flywheel slowly by hand while observing voltmeter. Voltage should switch between battery voltage and revolution.

If

voltage does not switch properly,

1-1.5

for each

replace ignition module.

Incorrect wiring can cause electronic ignition damage.

attach any lead

.to coil negative

6.

Install spark plugs and wires.

or jumper with power (such as

terminal.

being replaced, be sure new ignition module to positive black lead from module

If

ignition module is

to

connect red lead from

(+)

terminal of coil,

to

negative

(-)

terminal of

Do

B+)

coil.

a

(-)

not

IGNITION TIMING

The' ignition timing is preset at the factory and is not adjustable. For troubleshooting purposes,

to

make an approximate check of the ignition timing using reference marks on the blower housing and a chaff screen bolt (Figure 2). This check can be performed by a continuity test.

it

is possible

4. Rotate the flywheel slowly by hand in the clockwise direction until the voltmeter reading switches from approximately

1

volt to battery voltage. At this point, one of the chaff screen bolts should lie between the two timing marks on the blower housing. To recheck timing, the flywheel must be rotated another

complete revolution

in

the clockwise direction. Moving the flywheel back and forth across the reference timing mark will not activate the electronic ignition control.

5.

Install spark plugs and wires.

IGNITION COIL

To-test primary and secondary windings within the

ignition coil first make sure the ignition power is off and

coil is at room temperature of

1.

Use a Simpson 260

70°F

VOM

or equivalent.

(21

°C).

FIGURE

Continuity

1.

Pull spark plug wires off spark plugs and remove

Test

2.

IGNITION

TIMING

MARKS

spark plugs.

Accidental starting of the engine can result in severe personal

injury or death. Remove spark plugs before proceeding.

2. Turn ignition on.

3. Connect a voltmeter between the negative terminal (larger diameter of the two threaded posts) and a good engine ground.

(-)

M-1675

coil

2. Place a black lead on negative red lead

to

positive

(+)

(-)

coil terminal and

coil terminal. Primary

resistance should read between 2.90-3.60 ohms.

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

(Figure 3). Secondary resistance should read

between 14,500-19,800 ohms.

4.

If

either of the above resistances are not within

specification, replace coil.

OHMMETER

The electronic ignition produces

current which can cause elec-

trical shock.

Do

not touch electrical components

or wires while ignition

is

on.

8-2

FIGURE

3.

COIL

TEST

SPARK PLUGS

Check or replace spark plugs as recommended in the Periodic Maintenance Schedule (located in Operator's Manual). Replace spark plugs that show signs of fouling or electrode erosion.

BATTERY INSPECTION

Keep the battery

terminals

clean and tight. Push the cable terminal down flush with or slightly below the top of the battery post (Figure

5).

After making connections,

coat the terminals with a light application of petroleum

jelly or grease to retard corrosion.

Poor contact at the battery cable connections is 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.

Ignition

can result in severe personal injury.

Do

not smoke or allow any ignition source near the

of

explosive battery gases

battery.

Check battery cells with a hydrometer (Figure

4).

Specific gravity reading should be between 1.260 and

1.290 at

If

one or more cells are low on water, add distilled water

77°F

(25°C).

and recharge. Keep the battery case clean and dry. An accumulation of moisture or dirt will accelerate discharge and battery failure.

SPECIFIC

GRAVITY

READING

SHOULD

at

77°F

BE

(25°C)

BATTERY

FIGURE

Occasionally,

5.

BATTERY

it

may be necessary to jump start (charge)

JUMP

a weak battery using a charged booster battery.

POST

CABLETERMINAL

CABLE

CONNECTION

STARTING

If

jump starting is necessary, the following procedure is recommended

to

prevent starter damage, battery damage, and

personal injuries.

1.

Disconnect engine load.

2.

Use a battery of the same voltage

(1

2V) as is used

with your engine.

FIGURE

4.

SPECIFIC GRAVITY TEST

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

3.

the positive

(+)

terminal

of

the booster battery. Attach the other end of the positive cable to the positive

(+)

terminal of your engine battery.

Electrical arcing can cause severe personal injury. Do not allow

positive and negative cable ends to touch.

4.

Attach one end to negative

of

the negative booster cable (black)

(-)

terminal

of

booster battery., Attach other end of negative cable to a solid chassis ground on your engine.

8-3

5.

Jump starting in any other manner may result in

to-the

damage

battery or the electrical system.

Overcranking the engine can

I

minutes tor starter to cool

30

than

seconds.

cause starter damage. Allow

if

engaged for longer

Jump starting

a

battery incor-

rectly can cause battery to

explode, resulting in severe personal injury

death.

Do

not smoke or allow any ignition source near the battery, and do not jump start a frozen battery.

6.

Turn ignition switch to

ON

to start engine.

STATOR

5

or

This unit

FLYWHEEL

is

equipped with a permanent magnet flywheel

ALTERNATOR

alternator and solid-state voltage regulator-rectifier (Figure

6).

As

with all solid-state electrical units, pre-

cautions are necessary when servicing.

._

Reversing positive and negative bat-

tery connections or allowing engine to run without being connected to the alternator will result in engine electrical system damage.

Do

not

switch battery connections or allow engine to run

without being connected to the alternator.

Weak ignition spark or a discharged battery indicates

trouble in the charging system. Before testing the

engine's charging system, always check the battery for

serviceability.

VOLTAGE REGULATOR

20

AMP

VOLTAGE REGULATOR CONNECTIONS

FIGURE

MOUNTED BEHIND

BLOWER WHEEL

TOSTARTERORBATTERY

ES-1333-1

6.

FLYWHEEL ALTERNATOR SYSTEM

REGULATOR MUST BE GROUNDED

THROUGH MOUNTING BOLTS

CAUTION:

ES-1332

8-4

Keep these points flywheel alternator:

1.

Be sure engine is being run long enough and fast enough to recharge battery after each start. Charging system tests require a full charged battery. Alternator output is reduced

Also, power required for accessories reduces power

available to recharge battery.

2.

The regulator-rectifier has built in protection against open circuits or short circuits on the alternator output (B+) terminal. Either condition will cause the regulator-rectifier to shut off and appear as functioning. Prior to checking the regulator-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,

it may have insufficient power to "turn on" the regulator-rectifier.

Be sure regulator-rectifier plug (connector) is in-

3.

serted properly. Plug must bottom in receptacle; this eliminates any resistance due

Keep clean and tight. Make. sure alternator stator leads are not shorted

4.

together.

Be sure regulator-rectifier has a good ground

5.

connection. Mating surface for mounting must be clean and fasteners tightened properly.

6.

Never reverse the battery leads.

When the engine is running between observe the panel ammeter

connect a test ammeter). proceed with the

in

mind when testing or servicing the

in

direct proportion to engine rpm.

if

it is not

(+)

terminal to

if

the battery is extremely discharged

to

a poor connection.

1800

to

2600

(if

not already equipped,

If

no charging is evident,

Alternator Output

Test.

B+

rpm,

ALTERNATOR OUTPUT TEST

as

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

1.

Check battery voltage with unit not running. within specifications (Table proceeding to step

2.

With the engine-running, check the battery terminal voltage (regulator output) using a DC voltmeter. Voltage output should be within the values specified in Table replace regulator-rectifier assembly. less than specified, proceed to step

3.

Examine all wires for loose, corroded, broken connections, short circuits, etc. Check fuses. Repair as needed to assure complete circuits from regulatorrectifier and from battery negative rectifier case. engine running, proceed to

4.

Disconnect plug from regulator-rectifier and test the AC voltage at the plug with engine running. voltage reads more or less than specified in Table proceed to step DC voltage is

5.

Use the open Disconnect plug from the regulator-rectifier. Connect one ohmmeter test lead to a stator wire, connect the other test lead to ground. Reading should show an open (no continuity). stator must be replaced. tinuity conned one ohmmeter lead to each wire coming from the stator. Refer to Table 1 for resistance specifications. replace stator. specified and windings are not shorted or open, low AC voltage may be due to blower wheel assembly must be replaced.

1.

If

B+

terminal to battery positive

Rx1

scale on the ohmmeter for detecting an

or

ground in the stator (unit not running).

2.

voltage is greater than specified,

If

battery voltage remains low with

5.

If

low,

replace regulator-rectifier.

If

stator resistance readings are as

the Simpson

1)

charge battery before

(-)

terminal to regulator-

step

4.

AC voltage is as specified but

If

reading shows no con-

If

resistance is not as specified,

loss

of magnetism.

270,

If

voltage is

3.

(+)

If

terminal

it doesn't,

when

If

not

If

AC

If

so,

1,

8-5

TABLE

1.

TESTING

20

AND

35

AMPERE SYSTEMS

PROCEDURE

20

AMP

35

AMP

r

BATTERY REGULATOR

12

to

13 VDC 13.6

12

to

13

VDC

to

14.7

BASIC

VD

TEST

Refer

to

Alternator

STATOR

RESISTANCE

to

Refer

0.10

0.06

Alternator

Output Test

to

0.19

to

0.10

Ohms

TYPICAL

WIRING DIAGRAM

IGNITION

SWITCH

WITH

OIL

B+

ACCESSORIES

START

PRESSURE

SWITCH

BYPASS

SWITCH

OIL

PRESSURE

FOR

SHUTDOWN

:

CONDENSER

OIL

PRESSURE

SWITCH N

CONTROL

ES-1667

These typical wiring diagrams show the basic wiring necessary for operation of the engine. Your engine may differ in circuitry and features depending on how the

equipment

manufacturer chose

to

configure the final

product

Starting

System

ELECTRIC STARTER

Normally the starter will require little or no service other than possible brush replacement. However, accident or misuse, the starter requires service or overhaul, the following will provide the information necessary to perform this service.

if

through

1.

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

2.

Disconnect battery cable and electrical lead wires

from starter.

3.

Remove starter motor.

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. cranks engine slow, components. Failure to crank is normally caused by low

battery charge, defective battery cables, corroded or

\

poor connections, or low temperatures.

these variables, starter continues to crank slowly, starter

must be removed and repaired.

or

not at all, check start circuit

If

starter

after checking

Starter Removal

Accidental starting result in severe personal injury

death. Disconnect the negative battery cable and spark

plug wires while servicing engine, controls,

ciated equipment.

of

the engine can

or

asso-

SOLENOID

or

Starter Disassembly

1.

Remove solenoid (Figure

2.

Remove the two solenoid mounting screws and

remove solenoid.

3.

Scribe a mark across frame and rear bracket in assembly. Remove the

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.

“M”

terminal nut and wire lead from

8).

two

through bolts.

THROUGH

to

aid

SOLENOID

BUSHING

FIGURE

1.

STARTER

9-

1

COVER

BRUSH

ES-1665-01

MOTOR

8.

Push stopper toward pinion and remove snap ring

(Figure

9.

Remove stopper and overrunning clutch from

2).

armature shaft.

FIGURE

3.

INSTALLING STOPPER

CLUTCH

ES-1194

FIGURE

2.

REMOVING OVERRUNNING CLUTCH

10 Inspect starter for damaged or worn parts.

11.

Repair or replace all damaged or worn parts as

needed.

Starter

1.

2.

Assembly

Install seal in nose housing. Install overrunning clutch

on

the armature shaft.

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

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.

Lubrication: When starter motor

is

assembled apply

grease to each of the following points (Recom-

PS

No.

mended grade: Multemp

2):

Armature shaft spline Both bushings (Both ends of armature) Stopper on armature shaft Pinion gear Sliding portion of lever

ES-1622

3).

It

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.

8.

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

9.

Install rear bracket. Secure brush holder to rear

0.002

Retaining

Brush Through

Table

Bolts

to

0.02

inch

(0.05

if

rear bracket is replaced.

1.

Starter Assembly Torques

Screws

to

0.5

mm). New

bracket with two machine screws.

9-2

10. 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

“M”

on solenoid.

13. After assembly, adjust pinion clearance. Pinion

0.08

inch

(0.5

to

clearance should be 0.02 to if

not, check as follows (Figure

4):

2.0 mm);

A. Connect starter to a battery. Close switch. This

will shift pinion into cranking position.

B.

Push pinion back by hand and measure pinion clearance.

If

clearance does not 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.

COMMUTATOR

BARS

FIGURE

Testing Armature

5.

TESTING ARMATURE FOR GROUNDS

for

an

Open

Circuit:

Using an ohmmeter, check for continuity between the commutator segments.

If

there

is

no continuity (high resistance), the

segments are open and armature must be replaced.

PINION

FIGURE

SWITCH

BATTERY

12V

.4.

PINION CLEARANCE ADJUSTMENT

PINION

FRONT

CLEARANCE

ES-1623

Inspection and Testing

Inspect the starter components for mechanical defects

for

before testing

Testing Armature

core and the end of each commutator bar with a pair ohmmeter leads (Figure indicates a grounded armature. Replace grounded armature.

grounds or shorts.

for

Grounds: Touch armature shaft or

5).

A

low ohmmeter reading

Of

Testing Armature

locating shorts in the armature (Figure

for

a

Short

Circuit:

Use a growler for

6).

Place armature

in growler and hold a thin steel blade (e.g. hacksaw

blade) parallel to the core and just above it while slowly

rotating armature in growler.

to

cause the blade

vibrate and be attracted

A

shorted armature will

to

the core.

If

armature is shorted, replace with a new one.

BLADE

GROWLER

ES-1002

FIGURE

6.

TESTING ARMATURE FOR

SHORT

CIRCUITS

9-3

Commutator Inspection:

colored, clean with number

paper. Blow grit

out

If commutator is scored, rough, or worn, turn it down

If

commutator is dirty or dis-

00

to

000

commutator

of armature after cleaning.

in

lathe. Field Coil: Use an ohmmeter

between brushes.

If

there is no continuity, the field coil is

open and must be replaced. With field coil mounted

to

check for continuity

in

the frame, check for continuity between the field coil and frame. Replace frame assembly if there is continuity.

a

Overrunning Clutch: lnspect pinion and spline teeth for

or

wear

If

gear also. Rotate pinion.

damage.

pinion gear is worn or damaged, inspect flywheel ring

It

should turn free when turned in one direction, and lock when turned in the opposite direction.

damage.

Cleaning cleaning solution

Do

not clean overrunning clutch

overrunning

will

clutch

result

in

starter

in

liquid liquid

cleaning solutions.

Brushes: Clean around brushes and holders, wiping

all brush dust and

.4528

inch

(1

dirt.

If

brushes are worn shorter than

1.5

mm) replace them (Figure

WEAR

LIMIT

FIGURE

7.

BRUSH

WEAR

7).

LIMIT FIGURE

off

ES-1193

Solenoid: Push solenoid plunger

in

and release it. The

plunger should return to its original position. While

holding plunger all the way

between terminals

“M”

and “B”.

replace the solenoid (Figure

in,

check for continuity

If

there is no continuity,

8).

After replacing solenoid

check pinion clearance.

8.

TERMINAL

SOLENOID TERMINALS

“B”

ES-1345

Check for shorts between positive side of brush holder and brush holder base.

If

there is continuity, replace

holder assembly. Check for free movement of brushes.

All

brushes should move freely

in

the brush holders.

Bushings:

either the front or rear bushing

show

If

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

7/16

inch tap.

Do

not remove cap from front bracket. Thread capscrew, same size as tap, into bushing. Using a slide hammer remove bushing from

front bracket. Press new bushing into front bracket. Use

care not

to

distort inside diameter of bushing.

9-4

signs

Brush Replacement:

Cut old positive brush from pigtail at the brush. Be Careful not to damage field coil. Clean 1/4

to

3/8

inch

(6.5

to

9.5

mm) of brush end of pigtail

with sandpaper or emery cloth. (Figure

9).

Starter

Mounting

Before installing starter motor, make sure the starter

mounting surface on the engine base is clean and free

of

oil.

To

install starter use the following procedure. The

starter pinion gear lash does not require adjustment.

1.

Install starter motor and torque mounting capscrews

to

that specified in

ASSEMBLY

TORQUES.

PIGTAIL

STILL

ATTACHED

TO

FIELD

COIL

SMALL

FIGURE

CHAMFER

9.

BRUSH

REPLACEMENT

(approx.

SOLDER

MUST

EXTEND

BRUSH

LARGE

REPLACEMENT

SURFACE

CHAMFER

BRUSH

CLEAN

1/4

to

NOT

BEYOND

3/8

inch)

Push prepared end of pigtail lead into hole in replacement brush from the small chamfered side. Solder pigtail lead to replacement brush on the large chamfered side, using

50/50

tin/lead, rosin core solder and a standard 240/325 Watt soldering iron. Use a file to remove any excess solder that may extend beyond brush surface.

2.

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

Materialprotruding from soldered side surface of brush can cause equipment

damage.

Do

not use excessive solder or heat and file

any excess material from brush surface.

9-5

Engine

Disassembly

DISASSEMBLY/ASSEMBLY

When complete engine disassembly is necessary, first

remove all complete assemblies. Individual assemblies such as fuel pump and carburetor can be disassembled and repaired at another time.

Suggested Disassembly Order

1. Drain engine oil.

2. Disconnect all exhaust and electrical lines.

3. Removeengine from its mountingsand place upright in a suitable work area. per side provides a suitable fixture to hold the engine and prevent damage

oil

4. Remove

blower housings, etc.

5.

Remove flywheel.

6.

Remove ignition trigger and gear cover, being careful

7.

Remove 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 oil pump and cylinder heads.

10. Remove valves, springs, lifters, etc.

11. Remove camshaft and gear assembly.

12. Remove oil cooler.

13. Set engine on its back to remove oil base cover, oil pickup cup and oil pickup tube.

14. Remove connecting rods and pistons.

15. Remove oil base casting, crankshaft and lower 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.

fill

to

protect oil seal from keyway damage.

Suggested Assembly Procedure

Engine assembly is normally the reverse assembly procedure, observing proper clearances and torques. Use a torque wrench Coat the internal engine parts with oil as they are assembled. After the internal engine parts are assem-

bled, the engine should turn over by hand freely. Use

only genuine Onan parts and special

reassembling your engine.

1. Use proper bearing driver to install top main bearing after coating

2. Insert lower main bearings in oil base casting.

it

A 2 x

4 wood frame 10 inches

to

the crankshaft.

tube, and all housings, shrouds,

of

the dis-

to

assure proper tightness.

tools

when

with a light film of oil.

3. Insert crankshaft, oil base casting, and crankshaft gear.

4. Install pistons and connecting rods.

5.

Install oil pickup tube with its spring, oil pickup cup,

and oil base cover.

6.

Install oil cooler.

7.

Install camshaft and gear assembly; align crank

gear mak with cam gear mark.

8.

Install valve assemblies, oil pump, oil cooler, and

cylinder heads.

9.

Install all accessories such as oil filter, starter fuel lines and spark plugs.

10. Install gear cover with oil seal, trigger ring, and flywheel..

11. Check valve clearance.

12. Install all housings, shrouds, intake manifold, and oil fill tube. Always use a new oil

reinstalling the oil fill tube.

13. Fill engine oil.

fill

tube seal when

Operation

Start engine and check oil pressure. Run for approximately 15 minutes 'to bring engine

temperatures. Check for oil leaks, fuel leaks, and exhaust

leaks. Adjust carburetor and governor for speed and

sensitivity.

to

operating

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 the wide open position.

4.

Insert the compression gauge in one spark plug hole.

5.

Crank the engine and note the reading.

to

Refer There may be variations due to equipment, temperature, atmospheric conditions and altitude. These pressures are for a warm engine at cranking speed (about 300

rpm).

SPECIFICATIONS

is

used to determine the

in

for compression pressures.

Tappet

Adjustment

The engine is equipped with adjustable valve tappets. The valve tappet clearance should be checked and

Schedule

as specified in the (located

in

the Operator’s Manual). Adjust the

Periodic Maintenance

valve clearance only when engine is at ambient temperature. Proceed as follows:

1.

Remove ignition key

2.

Remove all parts necessary

to

prevent accidental starting.

to

gain access to valve

tappets.

3.

Remove spark plugs engine over

4.

Rotate crankshaft

by

to

ease the task of turning the

hand.

in

a clockwise direction until the right intake valve (viewed from carburetor end) opens and closes. Continue turning the crankshaft until the flywheel timing mark is lined up with the governor shaft on the gear cover. This should place the right piston

(#1)

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.

5.

The correct feeler gauge for the valve adjustment (see SPEClFlCATIONS) should pass freely between valve cap and tappet; a gauge should not (Figure

6.

To correct valve clearance, use a end wrench

to

turn the adjusting screw

0.002

inch (0.05 mm) thicker

1).

7/16

inch open

to

obtain the correct clearance. The screw is self-locking and will stay where

it

is set.

A

9/16

inch

(14

mm) open end wrench is required to hold the tappet while turning the adjusting screw.

7.

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

8.

Replace all parts removed in Step

screws securely. Torque valve cover bolts

2.

Tighten all

to

speci-

fied torque.

VALVE

A

properly functioning valve system is essential 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 the valve covers. be used

A

to

remove valves from the cylinder block.

valve stem seal

This seal must be replaced each time the valve

A

valve spring compressor must

is

used on the intake valve guides.

is

removed.

Place valves, springs, retainers, and tappets in a rack as

they are removed from cylinder block

so

they can

be

identified and reinstalled in their original locations. Discard old valve stem 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:

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

Burning and pitting are caused by the valve failing seat tightly. This condition is often caused by hard carbon particles on the seat. valve springs, insufficient tappet clearance. warpage, and misalignment.

Check the valve face for evidence of burning,

to

It

may also be due

to

weak

VALVE

SEAT

INSERT

VALVE

FIGURE

STEM

1.

SEAL

INTAKE

VALVE

CLEARANCE

\

ASSEMBLY

VALVE

ADJUSTING

SCREW

CLEARANCE

VT-1000

VT-1034

Warpage occurs chiefly in the upper stem due to its

exposure to intense heat. Out-of-round wear follows when the seat is pounded by a valve whose head is not

in line with the stem and guide. If a valve face is burned

or warped, or

Too

much clearance in the intake guide admits air and

if

the stem is worn, install a new valve.

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 temper-

atures which causes 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 are slightly pitted or burned on an

accurate valve grinder.

If

valves are badly pitted or have

a thin margin when refacing, replace them.

Driving out old valve guides can cause guide and tappet bore damage.

Do

not strike guide or tappet bores with driver during

removal.

Valve Guide Installation:

Run a small polishing rod 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 edge of each new guide with oil. Place guide in cylinder block and press

(8.7

mm) from valve box side

method of installation is shown in Figure

in

until guide protrudes

of

block. A suggested

ROD

3.

11

/32

inch

VT-1020

FIGURE

Stems and Guides:

guides for wear (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 that specified in

DlMENSlONS AND CLEARANCES

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

installed guide. 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 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 Removal:

Before removing valve guides, use an electric drill with a wire brush to remove carbon and other foreign material from top surface of guides. Failure to

to

perform this operation may result in damage

the

guide bores. Drive the guides out with a hammer

and valve guide drive.

VALVE

GUIDE

NUT

5/16-18 HEX

(2

REQUIRED)

5/16-18

FIGURE

3.

VALVE GUIDE INSTALLATION

Valve Stem Seals (intake only): Do

NUT

THREADED

ROD

not reuse valve stem

VT-1023

seals. Each time the valves are removed from cylinder block, a new seal must be used when valve is reinstalled.

Removing a valve after installing valve stem seal can cause seal damage.

not allow valve stem groove to come in contact

Do

with

valve stem seal after installation.

10-3

Valve

Spring:

ends, distortion; and tension.

Check valve springs for cracks, worn

If

spring ends are worn, check valve spring retainer for wear. Check for spring distortion by placing spring on a flat surface next square. Measure height of spring and rotate square edge

0.06

inch

to

measure distortion.

(1.5

mm) replace spring. Check spring tension

If

distortion exceeds

it

against

to

a

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:

deposits from valve

Remove carbon and combustion

seat.

Select proper puller size

determined by inside diameter of valve seat. On some

pullers use a new seat as a guide

(Figure

4).

Puller jaws must expand into cylinder block

to

adjust puller depth

at the point where bottom of valve seat insert rests on

cylinder block. Position puller on valve seat and tighten hex nut. Clamp cylinder block

slide hammer

blow

with the slide hammer.

to

puller. Tighten hex nut between each

to

a solid bench. Attach

Valve Rotators:

Free rotating valves are used for intake and exhaust. While in the open position, the valves must rotate freely.

Valve Seats:

Inspect valve seat inserts.

If

seats are in serviceable condition clean seat up by using either a seat cutter

or

seat grinder.

If

seats are loose, cracked

or

severely pitted, new ones must be installed. Remove valve seat inserts using a valve seat removal seat insert bores in cylinder block are damaged

so

that a press fit cannot be obtained when installing

tool.

If

or

valve worn

new standard size valve seat inserts, the bores must be machined for an oversize seat.

USE

NEW

VALVE

SEAT

ADJUST

PULLER DEPTH

TO

VALVE

INSERT

(USE

CHECK

FOR

BURRS

INSERTING

SEAT

DRIVER

PROPER

THIS

SURFACE

BEFORE

TOOL)

SEAT

PULLER

FIGURE

4.

JAWS

VALVE SEAT REMOVAL

C-1104

VT-1025

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 hammer seat insert in

to

install the insert (Figure

so

the insert enters the recess evenly.

5).

Drive the valve

Make certain that the valve seat insert rests solidly on

the bottom

of

the recess all the way around its

circumference.

To

assure a tight valve seat fit and eliminate the danger of seat loosening in the bore, valve seat must be staked. Use Onan valve seat staker

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

tool a sharp blow place.

It

will be necessary

to

wedge new valve seat securely in

only.

to

refinish valve seat inserts

before installing valves.

10-4

TAPPETS

Very little wear takes place on tappet diameters tappet bores.

If

the clearance between tappet and bore in cylinder block exceeds specifications, replace the tappet. Oversize tappets are available.

Inspect the tappet faces which contact camshaft lobes

for roughness, scuffing,

worn tappets.

If

tappets are worn, inspect camshaft for

or

concave wear. Replace any

wear.

or

in

VALVE FACE AND SEAT GRINDING

Before installing new valves inspect valve seats for proper valve seating. If used

valves are reinstalled, the valve stems should be cleaned

and valve faces ground

Refinish valve seats

valves and seats, remove all evidence of pitting and

grooving.

If

end of valve stem is pitted clean it up on the refacer wheel. usually enough

to

square stem and remove any pits burrs. The valve guide should be thoroughly cleaned. valve guide is worn,

or

parts must be replaced. 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 faces. The one degree difference the interference angle (Figure greater than that of the valve face. This assures contact at the maximum diameter on valve seat seating surface.

or

previously used valves,

to

their specified angles of

to

a

45°

angle. When refacing

or

worn, true it and

A

very light grind is

44°.

valve is warped, the necessary

to

lap the seating sur-

in

angles is defined as

6).

The seat angle is

or

If

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 is warped, a knife edge will be ground (Figure head due removed

to

the large amount

to

completely reface valve. Heavy valve heads

7)

on part

of

metal that must be

or

all of the

are required for strength and good heat dissipation. Knife edges lead

to

due

heat localizing on the edge.

to

breakage, burning, and pre-ignition

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 worn

to

true a valve indicate whether valve head is

or

warped.

WARPED

VALVE WITH KNIFE

EDGE

GOOD

MARGIN

FIGURE

7.

VALVE

HEAD

KNIFE

INCH

MARGIN

7)

or

EDGE

MINIMUM

(.E

MM)

is

warped,

M-1184

FIGURE

Refinish valve faces machine. The grinding. Check removed. check

to

If

see

6.

VALVE INTERFERENCE ANGLE

to

first

cut from valve face must be a light

if

there is an unevenness of metal being

only part of valve's face has been touched,

if

valve is properly seated in machine

valve is warped, worn,

a

44°

angle on a valve refacing

or

distorted. When cut is even

VT-1021

or

if

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 and the width of the seat band should be

3/64

inch

(0.8

to

1.2

mm) wide. Grind only enough

45

degree stone

1/32

inch

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

line

of

contact should

be

at the center of the valve face.

at

ail points. The

10-5

to

FLYWHEEL

Removing the flywheel is a relatively simple process, but the following procedure must be followed damage

1.

to

the gear case and possible injury to the

Turn the flywheel mounting screw outward about

two turns.

Incorrect flywheel removal can

result in severe personal injury.

Do

not remove flywheel screw completely when

using flywheel puller.

2.

Install a flywheel puller on the flywheel (Figure

FLYWHEEL

to

avoid

8).

GEAR

COVER

After removing the mounting screws, tap the gear cover

gently with a

soft

faced hammer to loosen

it.

When installing the gear cover, make sure the pin in the gear cover engages the nylon lined (smooth) hole in the governor cup. Turn the governor cup

so

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. seal (Figure

Be

careful not to damage the gear cover oil

9).

FLYWHEEL

MOUNTING

FIGURE

3.

Turn the puller bolts in, alternately, until the wheel

8.

FLYWHEEL PULLER

SCREW

snaps loose on the shaft.

Improper flywheel removal can cause gear case damage.

use any tools to pry against gear cover when

removing flywheel.

4.

Unscrew the puller from the flywheel, remove the flywheel mounting screw and washer and pull the flywheel off the shaft. Take care not to drop the wheel.

A

bent or broken fin will destroy the balance.

CS-1000

Do

not

ROTATE

CUP

SO

INTO

THE

HOLE

BUSHING

ROLL

GOVERNOR

ROLL

METAL

LINED

OR

PLASTIC

IN

THE

FIGURE

FITS

CUP

I

GOVERNOR

9.

GEAR COVER ASSEMBLY

GOVERNOR

YOKE

OIL

CUP

GOVERNOR

IF

FEELER

ENTER

FALLEN

(Smooth

Toward

SEAL

WILL

HOLE

OUT

SHAFT

Side

Cup)

IS

PROPERLY

ASSEMBLED

DIMENSION SHOWN

ON

DRAWING

BE

AS

THE

WILL

INDICATED

GOVERNOR

CUP

FLYBALL

5

BALL

GOVERNOR

FLYBALL LOCATIONS

10

BALL

GOVERNOR

CS-1238

GOVERNOR

FIGURE

CUP

10.

GOVERNOR CUP DETAILS

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

has a flat spot; the ball spacer

if

its arms are worn

otherwise damaged; the gear/spacer assembly

on gear hub, and the governor cup grooved spinning

or

rough. The governor cup must be a free-

fit

on the camshaft center pin,

if

the race surface is

but

without any

if

loose

off

or

excessive play.

When installing the governor cup, tilt the engine

gear is up, put the flyballs in place (Figure

10),

so

the

and

install the cup and snap ring on the center pin.

The camshaft center pin extends out

3/4

inch

(19

mm) from the end of the camshaft. This distance provides an in-and-out travel distance of 7/32 inch

(5.6

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

cannot be pulled outward

If

the center pin extends out

the flyballs properly.

(5.6

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

or

removed without damage.

too

far, the cup will not hold

If

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, remove the cylinder head and valve assemblies.

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

puller to the puller ring and proceed to remove the gear. Each liming gear is stamped with

gear teeth must mesh

so

“O”

near the edge. The

that these marks exactly coincide when the gears are installed in the engine. When installing the camshaft gear and shaft assembly, be sure the thrust washer

is

properly in place behind the camshaft gear. Then install the crankshaft retaining washer and lock ring.

FIGURE

CRANKSHAFT

'GEAR

INSTALLING

GEARS

11.

TIMING GEAR REMOVAL AND INSTALLATION

VT-1029-01

4.

Turn the crankshaft until the piston is at the bottom

of

its

stroke and remove the connecting rod nuts. Lift

from

the rod bearing cap

the rod and push the rod

and piston assembly out through the top

cylinder using

hammer handle.

Do

not scratch the

a

crankpin and cylinder wall when removing the

piston and rod..

5.

Mark each piston and returned

to

their respective cylinders after overhaul.

rod

assembly

so

they can be

Keep connecting rod bearing caps with their respective rods.

6.

Remove the piston rings from the piston with a

13).

piston ring spreader (Figure

Remove the piston

pin retainer and push the piston pin out.

of

the

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 cooler from the

engine.

3.

Remove the ridge from the top

of

each cylinder with a ridge reamer before attempting piston removal (Figure

12).

Improper piston removal can cause piston damage. Use ridge

reamer

to

remove cylinder ridge before removing

piston.

FIGURE

7.

Remove dirt and deposits from the piston surfaces

13.

REMOVING PISTON RINGS

with an approved cleaning solvent. Clean the piston ring grooves with a groove cleaner or the end of a

piston ring filed

must be taken

to

a sharp point (Figure

not

to

remove metal from the groove

14).

sides.

Care

FIGURE

12.

REMOVING RIDGE

FROM

CYLINDER

10-8

Improper piston cleaning can

'cause piston damage.

use

a caustic cleaning solvent or

cleaning pistons.

8.

Clean the connecting rods passages with compressed air.

in

solvent.

wire

Blow

Do

brush

out

not

for

all

FIGURE

15.

CHECKING RING SIDE CLEARANCE

Measuring Pistons:

FIGURE

14.

PISTON

GROOVE

CLEANING

Inspection

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

Piston Inspection:

1.

Inspect the pistons lands, skirts and pin bosses. Check for wear at the ring lands using a new ring and feeler gauge (Figure

15).

Replace the piston when the

side clearance of the top compression ring

reaches that specified in

CLEARANCES.

2.

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

top

for

fractures at the ring

DIMENSIONS AND

or

damage

ring land indicates preignition.

Refer'

determine where

to

DIMENSIONS AND CLEARANCES

to

measure piston to be sure the

total clearance follows specifications.

to

Measuring Piston Rings:

1.

Install the

the piston and push the ring

piston

ring in the cylinder bore. Invert

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 of filing ring ends to increase the end gap is not recommended.

16).

If

the ring end gap does not meet specifications, check for the correct set of rings and the correct bore size. cylinder bore that size will reduce the end gap

is

0.001

inch

(0.03

0.003

mm) under

inch

mm).

A

(0.08

CYLINDER

BLOCK

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.

Cleaning

After removing pistons, crankshaft, cylinder heads, etc.. inspect block for cracks and wear. serviceable, prepare

1.

Scrape all old gasket material

it

for cleaning as follows:

oil by-pass to allow cleaning solution

If

block

from

block. Remove

to

contact

is

still

inside of oil passages.

2.

Remove grease and scale from cylinder block by agitating in a bath of commercial cleaning solution or hot soapy washing solution.

3.

Rinse block in clean hot water

to

remove- cleaning

solution.

Inspection

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

it

unfit for further use.

FIGURE

Connecting Rod Inspection:

16.

POSITIONING OF PISTON RING AND MEASURING OF END GAP

Replace connecting rod bolts and nuts that have damaged threads. Replace connecting rods that have deep nicks, signs of fractures, scored bores, or bores with dimensions which exceed that specified

DIMENSIONS AND CLEARANCES.

in

1.

Make a thorough check for cracks. Minute cracks 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.

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.

Cylinder Bore Inspection:

Inspect cylinder bores for scuffing, scratches, wear, and scoring. If cylinder bores are scuffed, scratched, worn, or scored, they must be rebored and hone3 for the next oversize piston.

When the appearance of cylinder bores is good and there are no scuff marks, check cylinder bore for wear or out of roundness as follows:

1.

Check cylinder bore for taper, out of round, and wear with a cylinder bore gauge, telescopic gauge. or inside micrometer. These measurements should be taken at four places: top and bottom of piston ring

to

travel, parallel and perpendicular

shaft (Figure

17).

axis of crank-

10-10

2.

Record measurements taken a? top and bottom of piston travel as follows:

A.

Measure and record as

diameter (parallel

to

“A”

the cylinder bore

crankshaft) near the top of

cylinder bore.

Measure and record as

B.

“B”

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

Measure and record

C.

as

“C”

cylinder bore

diameter (perpendicular to crankshaft) near the top of cylinder bore.

TOP

END

OF

CYLINDER

RING

WEAR

AREA

Measure and record as

D.

“D”

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

Reading

E.

reading

“A”

subtracted from reading

“C”

subtracted from reading

“B”

“D”

and

indi-

cates cylinder taper. If

cylinder taper exceeds that specified in

DIMENSIONS AND CLEARANCES

hone cylinder

F.

Reading

reading

to

the next oversize.

“A”

compared to reading

“B’

compared to reading whether or not cylinder is out of round. round exceeds that specified in

AND CLEARANCES

the cylinders must be

rebore and

“C”

and

“D”

indicate

If

out of

DIMENSIONS

rebored and honed to the next oversize.

Reboring the Cylinder

Rebore and hone engine whenever cylinder bore is worn, damaged, out of round, or exceeds specifications.

A

worn cylinder bore should be

resized to the smallest standard oversize diameter at which it will clean up. The final finish and borediameters should then be obtained by honing. Final bore diameter should equal the standard diameter added to the oversize.

if

cylinder taper

Improper boring will

result

in engine

damage. Boring must be done

qualified mechanics.

After boring to the correct oversize cylinder bore

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 pre-

cautions:

1.

Make sure cutting tool is properly ground before

using it.

2.

Be sure top of engine block is smooth and deposit

free.

by

FIGURE

17.

METHODS

OF

A

CYLINDER BORE

OF

MEASURING THE DIAMETER

10-1

1

3.

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.

Make an initial rough cut, followed by a finish cut.

Then hone cylinder bore to the specified oversize.

Honing Cylinders (Using Precision

Refer

to

hone manufacturer's recommended grit site to

produce specified surface finish of

Hones)

20

to

40

RMS.

Too

rough of a finish will wear out the rings and too smooth of a finish can retard piston ring seating:

1. Position block solidly for either vertical

or

horizontal honing. Use either a drill press or heavy-duty drill which operates at approximately

2.

Follow hone manufacturer's instructions for the use

250

to

450

rpm.

of oil or lubricant on stones. Do not use lubricants with a dry hone.

3.

Insert hone in bore and adjust stones to fit snugly to

the narrowest section. When adjusted correctly, the

hone should not shake or chatter in cylinder bore, but will drag freely up and down when hone is not running.

Deglazing Cylinder Bores

Deglaze the cylinder bores

and

no

wear or out of round beyond specifications before installing new rings. Deglazing gives a fine finish. but does not enlarge cylinder diameter, pistons with new rings may still be used.

The reason for deglazing a cylinder is to provide cavities to hold oil during piston ring break-in.

1.

Wipe cylinder bores with a clean cloth which has been dipped in clean, light engine oil.

2.

Use a brush type deglazing tool with coated bristle tips to produce a crosshatch pattern in the cylinder bore.

3.

Use a slow speed drill to drive the deglazing tool. Move deglazing tool up and down in cylinder (10 to

12 complete strokes) rapidly enough

crosshatch pattern (Figure 18).

if

there are no scuff marks

so

the original

to

obtain a

4.

Connect drill

to

hone and 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

As

because it is smaller.

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 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 by moving the rotating hone down in cylinder bore about

7.

Clean cylinder bores thoroughly with soap, water and clean rags.

23

degrees. This can be achieved

(250

to

450

rpm) up and

40

times per minute.

A

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.

8. Dry crankcase and coat

it

with oil.

six

PRODUCECROSSHATCHSCRATCHES

FOR

FAST

RING SEATING

FIGURE

use gasoline, solvents, or commercial cleaners to

clean cylinder bores.

4.

Clean cylinder bore thoroughly with soap, water

18.

CROSSHATCHING

Improper cylinder cleaning will

result in engine damage.

AVOID

THIS

FINISH

Do

and clean rags. Continue cleaning until a clean white rag shows no discoloring when wiped through cylinder bore.

not

CRANKSHAFT

Clean crankshaft thoroughly and inspect journals for scoring, chipping, cracking, or signs of overheating.

.If

crankshaft has overheated, is scored, or excessively

worn, reconditioning or replacement will be required. Examine bearing journals for cracks

if

overheating has

occurred.

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. Metalizing of bearing journals is 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 of this type. Undersize main bearings and connecting rods are available.

Whenever making major repairs on the engine, always

inspect the drilled passages them

to

remove any foreign material and to assure

of

the crankshaft. Clean

proper lubrication of the connecting rods.

BEARINGS

With camshaft and crankshaft removed, measure all bearing journal diameters. Measure inside diameter of bearings. Refer determine

to

DIMENSIONS AND CLEARANCES

if

measurements are within specifications.

to

ALIGN HOLE

WITH

IN

BEARING BORE OUTSIDE

IN

HOLE

BEARING

TOP

BEARING

BOTTOM

FIGURE

CAMSHAFT

\

CAMSHAFT

19.

CAMSHAFT

BEARING

PRESS

I

BEARING

BEARING IN

(1

2.7

mm)

OUTSIDE

BEARINGS

OF

BLOCK

CT-1094

Visually inspect bearings and journals. Replace any bearing that

is

scored, chipped, pitted or worn beyond

specifications.

Camshaft Bearings

Replacement camshaft bearings are precision type which do not require line reaming installation. Use a press or a suitable driver bearings. Support casting to avoid distortion and to avoid damaging the bearing bore during removal and installation.

Clean. outside of bearing and bearing bore in the block.

Before installing bearings use Locktite

on outside diameter of bearing. Use a combination

bearing driver

to

install bearings.

Place the top camshaft bearing on the crankcase over

the bearing bore with the lubricating hole lined up with

the hole in block (Figure

19).

Be sure to straight. Press in the top bearing flush with the outside end of the bearing bore. Lubricating hole in the bearing

must be aligned with the hole in the block after

installation.

or

line boring after

to

remove

Bearing

start

the bearing

Mount

Press in the bottom camshaft bearing to the dimension shown (Figure

19).

Lubricate bearing surfaces with oil

after installing.

Crankshaft

Bearings

New crankshaft main bearings are precision type which do not require line reaming or line boring after installation. Use a press or a suitable driver to remove bearings. Support casting to avoid distortion and to avoid damaging the bearing bore during removal and installation.

Inspect the top and bottom main bearing lock pins for damage. Replace

if

necessary,

Before installing main bearings expand bearing bores by placing the casting in an oven heated

(94ºC).

Cool

the precision bearings

to

200°F

shrink them

if

possible.

10-1

3

TOP

MAIN

BEARING

BORE

The bottom main bearing consists of two bearings. Use

of

a combination driver and lubricate the outside bearings with dimension shown (Figure must line up

1

/8"

diameter pin can be inserted into hole. Lubricate

SAE

30

oil before installing them to the

21).

Oil holes in the bearings

with

those drilled in the engine block

the

so

a

main bearings lightly with oil after installation.

ALIGN

BEARING

NOTCHES

FIGURE

WITH

REPLACEMENT

TOP

MAIN

BEARING

20.

TOP MAIN BEARING INSTALLATION

Replacement top main bearing has the thrust washer

attached to the bearing.

Do

not add an additional thrust

washer to this.

Breathing vapor from towelette and

prolonged contact with skin can be

harmful. Use

only

in

we//

ventilated area and avoid

prolonged contact with skin.

Before installing the top main bearing use the towelette included with the bearing kit to clean the outside bearing and bearing bore in the block. Allow three

of

the

to

four minutes to dry. Apply Locktite from the small tube to the mating surfaces of the bearing and the bearing bore. Align the lock pin and oil holes in the bearing with the

lock pins and oil holes in the bearing bore (Figure

20).

Use a combination driver and install the bearing flush with the block. The oil holes must be at least half open after installation. Wipe

off

excess Locktite around the bearing. Allow at least one hour at room temperature for hardening.

OIL

BASE/BEARlNG

,005''

(0.127mm)

Place the thrust washer on the oil base

so

the notches fit over the lock pins and the grooves are facing away from the oil base (Figure oil base. insert crankshaft into

oil

base on engine block.

moved

off

lock pins before tightening oil base or

22).

Place a new oil base gasket on

top

main bearing. Install

Be

sure thrust washer has not

lock

pins will be damaged.

OIL

BASE

FIGURE

Tighten

ASSEMBLY

22.

CRANKSHAFT

!-

the

oil base

TORQUES

the crankshaft endplay (Figure that specified

in

endplay exceeds limits remove

between the. thrust washer and

A

THRUST

WASHER

GROOVES

OIL

BASE THRUST WASHER AND

SHIM

ENDPLAY

to

the torque recommended in

AND SPECIAL TOOLS.

23)

and compare

DIMENSIONS AND CLEARANCES.

oil

base and add shim(s)

oil

base. Install oil base,

Check

it

with

LS-1186

making sure; the thrust washer and shim(s) notches line up with the lock pins. Torque oil base and check endplay.

If

FIGURE

21.

BOTTOM MAIN BEARING INSTALLATION

LS-1183

10-14

MEASURE

HERE

EN

FIGURE

BLOCK

23.

CRANKSHAFT ENDPLAY

CT-1095

CHECKING CONNECTING

ROD

BEARING OIL SEALS

CLEARANCE WITH PLASTIGAUGE

1.

Make certain that

so

they are installed in their original positions. Using

a

clean dry cloth, thoroughly clean all oil from

crankshaft journal and connecting rod.

2.

Place a piece of correct size Plastigauge in the bearing cap the full width of the journal surface and about

1/4

inch

Rotate the crankshaft about

3.

dead center and reinstall the-bearing cap; tighten rod bolts

to

TORQUES

crankshaft.

Remove bearing cap. The flattened Plastigauge will

4.

be found adhering

crankshaft.

Compare flattened Plastigauge with thegraduations

5.

on Plastigauge envelope The number within the matching graduation on the

envelope indicates total clearance in millimeters or thousandths of an inch.

all

parts are marked or identified

(6.35

mm)

off

center (Figure

30

degrees from bottom

the torque specified in

AND SPECIAL TOOLS.

to

either the bearing cap or

to

determine clearance.

ASSEMBLY

Do

not turn the

24).

The gear cover and oil base have replace the oil seals. Drive

oil

seals out from the inside,

being careful not to damage the

to

be removed to

oil

base and gear cover

surfaces.

Before installing oil seals

fill

the space between lips with

a multi-purpose grease.

Clean old sealing compound

off

of gear cover

oil

seal mounting surface before installing new oil seal. Install the gear cover oil seal to the dimension shown (Figure

Use a seal expander when installing oil base

oil

25).

seal to prevent damage to oil seal. Install, oil seal flush with outside

OIL

of

oil base (Figure

SEAL

21)

MOUNTING

OF

I

GEAR

FACE

COVER

FIGURE

24.

MEASURING BEARING CLEARANCE

A

GEAR

COVER

FIGURE

I

GEAR

COVER

OIL

25.

GEAR COVER OIL SEAL

THIS

SHOULD

OLD SEALING COMPOUND

BEFORE

SEAL

GEAR

BE

INSTALLING

COVER

SURFACE

CLEANED OF

SEAL

ALL

LS-1163

1. Lubricate all parts with engine oil.

2. Position piston on its respective rod and install the

b pin.

3. Install the rings on the pistons starting with the oil control ring (Figure 26). Use a piston ring spreader to prevent twisting or excessive expansion of the

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 be 180 degrees from the gap of that ring.

PISTON ASSEMBLY

4. Tap the piston down into the bore with the handle end of a hammer until the connecting rod is seated on the journal (Figure 27). Install the bearing cap on

the rod.

5. Install one fastener and tighten to 5 ft-lbs (7 Nm). Repeat this for the other fastener. Tighten both

fasteners down to the torque specified in ASSEMBLY

TORQUES.

OIL HOLE* OR

TOWARD T

COMPRESSION

FIGURE 26. PISTON RINGS

RINGS

CT-1047

INSTALLATION OF PISTON IN CYLINDER

1. Turn the crankshaft to position the number one rod bearing journal at the bottom of its stroke.

* OIL HOLE NOT USED, LATER PRODUCTION

CONNECTING ROD

CT-1048

2. Lubricate the number one piston assembly and inside of the cylinder. Compress the rings with a ring

compressor (Figure 27).

3. Position the piston and rod assembly in the cylinder

block. Oil squirt hole of connecting rod must face camshaft.

FIGURE 27. INSTALLING PISTON AND CONNECTING ROD

6. Install the remaining piston and rod in the same manner. Crank the engine over by hand to see that

all bearings are free.

7. Install the oil cooler with a new gasket.

8. Install the cylinder heads. See Cylinder Headsection

for torques and torquing procedure.

9. Replace oil and break in engine.

lo-16

CYLINDER

HEADS

3.

Use new head gaskets and clean both :he heads

Remove the cylinder heads for carbon cleaning and and the cylinder block thoroughly where the gasket change at intervals specified in the Periodic gaskets rest.

Maintenance Schedule (located Manual).

1.

Use a

1/2

inch

(13

mm) socket wrench

cylinder head bolts or nuts. Lift heads

Torquing or removing cylinder

heads when hot (above

[37°

C])

will result in head damage. Allow heads to

cool to below

100°

F

(37°

removing.

2.

After removing heads, clean out all carbon deposits.

Be

careful not to damage the outer sealing edges

where gaskets

fit.

The heads are made of aluminum

in

the Operator's

off.

C)

before torquing

to

remove

100°F

or

Cylinder Head Installation

1.

Place a head gasket on the cylinder block and align

the holes in the gasket with the holes in the cylinder

block. While holding the gasket against the cylinder head, carefully install the cylinder engine.

not attempt

to

slide the head

Do

through the gasket without the cylinder block behind

it

or the gasket may tear.

Follow the head torque sequence shown in Figure

2.

28. Tighten all bolts

(14

Nm),

then

TORQUES.

Recheck all head bolts for correct

to

5

ft-lbs

to

the torque specified in

torque.

(7

Nm), then

head

ASSEMBLY

10

and can be damaged by careless handling.

on the

bolts

ft-lbs

NO.

1

CYLINDER

FIGURE

28.

CYLINDER HEAD TORQUE SEQUENCE

10-1

7

NO.

2

CYLINDER

C-1002

Right at home.

Product

shown herein

Wheel

right designs

notice

Tractors & Riding

Mowers

information and specifications are

as

of the time of printing.

Horse

Products,

to

change product specifications,

and

without

Inc. reserves the

standard

equipment without

incurring obligation.

PRINTED

IN

U.S.A.

1089

PART

NUMBER 810713R1

Toro 74021, 74041, 74101, 74120, Y1-16OE01 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual