Generac Power Systems GTV99O, GTV760 Service Manual

Malual Part

No. OE2Oal

fr

SERVICE

MANUAL

F

["J

*.1

POWER

P.O.

Box 297

Phone:

[phone]

P nted

in

lJ.s.A

GiENEFIAC'

SYSTEMS,

INC.

.

Whitewater, Wl . 53190

GTV

-1990/760
V-TWIN

OHVIENGINE

Fax:.

(262)

472-6505

Firsl Edition lssued - bi/xrxx

?J

FOREWORD

This

manualhas been written and

published by e

tHeUC@

pOWe

n

SYSTEMS,

lNc. to aid our dealers' mechanics,

company

servlce

per_

sonneland

general

consumers when servicingthe

products

des(ribed

herein.

It

is assumed

that these

personnelare

familiarwiththe

servi(ing

pro_

cedures

torthese

products,^or like or similar

products,

manu{actured

and

marketed

byGENERAC@

PowER

sYsTEM

s, lNc. lt is alto assumed

that they

have been

trained

in the

recommended

servicing

procedures

for the5e

products, which

includes

the use

of mechanics

hand

tools

and

any specialtools

that might

be

required.

Proper

service

and repair

is imPonant

to the safe,

economical

and

reliable operation

of the

products

de5cribed

h€rein

The trou'

bleshootirlg,

testing,

service

and

rePair

procedures

recommended

by

cEtltnlc@ PowrR

sysTEMs,

lNc. and

described

in this

manual

are

effective

methods

of

performing suah operation5.

Some

ofthese

oper-

ations

or

procedures

may

require

the use

of specialized

equipment'

Such equipment

should

be

used

when and

as recommended

we

(outd

not

possibly

know

oI and

advise

the sewice

trade

of

all

conceivable

pro(edures ot methods

by

which a

service

might

be

per-

formed,

nor

ot any

possible hazards

and/or results

ot each

procedure

ormethod,We

have notundertaken

any

such wideevaluation

There-

{ore, anyone

who

uses a

Procedure

or method

not

recommended

by

the manu{acturer

must {irst

satisly

himselfthat

neither

his sa{ety,

nor

the

product's satety,

will be endangered

by the

service

or oPerating

procedure

selected,

Atl

information,

illustrations

and sPe(ifications

contained

in this

manual

are based

on the

latest

product information

available

at the

iliili

"'tri.n",

However,

GENERAC@

PowER

sYsrEMs,

lNc'

reservesihe

rightto

(hange,

alter

orotherwise

improve

the

product

at any

time

without

Prior

noti(e.

some components

or assemblies

o{

the

Product

degcribed

in this

manuat

may

not be

(onsidered

rePairable.

Disassembly,

repair and

reassembly

oI such

components

may

not be inctuded

in this

manual'

The engines

described

herein

may be used

to

power

a wide

variety

oI Droducts.

Service

and

repair instructions

relating toany

such

prod'

uatsare

notcovered

in this

manual. Forinformation

pertainingto

use

of these

engines

with other

products,

re{erto

any

owne/s

or service

manuals

pertaining

to said

products.

?.,

TABLE OF

CONTENTS

RULES FOR

SAFE OPERATION

DIMENSIONS

AND

FEATURES

4-CYCLE

ENGINE

THEORY

SEcTION

1: GENERAL

INFORMATION

SECTION

2: IGNITION

SECTION 3;

CARBURETION

SECTION

4: GOVERNOR

CONTROLS

AND

GOVERNOR

SECTION

5: CYLINDER

HEAD AND VALVES

SECT|oN

6: El.ECTRlc

SIARIER

SECNON 7:

ALTERNATORS

SECTION 8:

LUBRICATION

SYSTEM

SECTION

9:

ENGINE DISASSEMBLY

SECTION

lO: CYLINDER

AND CRANKCASE

COVER

SECTION

11: CRANKSHAFT

AND CAMSHAFT

SECTION

12: PISTON,

RINGS AND

CONNECTING

ROD INSPECTION

AND

ASSEMBLY

SECTION

13r ENGINE

ASSEMBLY

A WORD ABOUT

SPECIALTOOLS

Many ot

the

prccedurcs

depicted in this manual

rcquite the

use of special

tools. Some of

the tools

reouired are available

as Genetac

patts

and ate

listed as such in

this manual.

ATTENTION!

cenerac

Power Systems

does notapprove orauthorizethe

use ol these

eng ines- on AllTerrain

Vehicles

(AW"s);

go-carts,

motorbikes, aircraft

products,

personal

watercraft,

or vehicles

intended

for use

in

(ompetitive

events. Use

ofthese engines

in such

applications could

result

in

property

damage, serious

injury

(in.luding

paralysis),

ot even

death.

t

RULES

FOR SAFE OPERATION

lfyou

do not understand any

podion

of

this manual, con-

tad Cenerac

or

your

nearest

Generac

Authorized S€rvice

Dealerfor starting, operating and

setulclng

procedures.

Throughoutthis

pubIcilion

and ontags

and decaG affixed

to the

engine, DANGER,

WARNING

and CAUTION blocks

a€ used to aled

you

to speclal instrudion

about;

panicu,

laropefalion that may be hazardous

if

performed

lncorrectly

or carclessly. ObseNe them

carefully.

These safety warnings

cannot eliminate

the

hazards

that

they indicate.

Stict

compliance with

the specialinsVuctions

whrle

per{or"l

ng

the serv

(

p

plLs

'

comaor

.Frse'

ara

majo.

The following definitions

apply io oANGER,

WARNING,

CAUTION and NOTE

blocks found throuqhoutthe

manua

These safety synbols indicate

the follawing:

DANGER: After

lhis heading

you

can read han-

dling, installing,

op€rating

or sewicing instructions

that, if not

rtrictly compiied

with, witt resutt in

personalinjnry

WARNING:

After

this heading

you

can read han-

dling.

installing,

operating or servicing

instructions

that, if notnrictlycompli€d

with,

may result in

per-

sonal injury,

CAUTION: After

this heading you

can read instruc-

tions for

handling, installing,

operating

orservi(ing

the

enginethat, il

not stri.tly

complied wirh, may

result

in damage

to €qu;pnent

and/or

property

NOTE:

After this heading you

<an rcad explanatory

statements

that rcquirc

special emphasis.

These

symbols indicate

the fo lowing:

Points

out important saiety

inlormation that, ilnot

lollowed,

could

endanger

personal

salety and/or

Prope

y

ofyourseli

and others.

RULES FOR SAFE OPERATION

Studythese RIJLES FOR SAFE OPERATION

carefu

y

before

operalinq

or servicing th is equipment. Become familia

r w th

Tfp OWNFR'5 N.4ANUA

adwith

_eergirF

Tl-eengrnecar

operalesa{€ly,

efficiently and reliablyonly if it is

properly

oper

ated

and maintained. Many

accrdents ar€ caused

by

failing

to

tolow

simp

e and fundamentalrules

or

precauttons.

Generac

cannot

possiby

anticipate

every

possible

circ!m-

nance

that might involve

a hazard.

The warninqs in

this

manualand

on tags

and decals

affixed tothe

equipmeni, arc

therelore, noi all-inclusive.

tf

you

use a

procedure,

work

method

or operating technique

Generac does notspecifically

recommend, you

must satsfyyoLr6elf

that lt is

safe for

you

and

olhers. You must also make

sLire the

procedlre,

work

method

or operaiing t€chnique

that

you

choose

does not

renderthe

engine to be unsafe.

DANGERT Do not tamper

with the engine

gov-

erned

tpeed. High operating speeds

are dang€rous

and increare

the rhkof

personal

injury

or damag€

to

the equipment. Operating

at low speeds with

heavy load may shorten

the engine's ljfe.

A

Potential

explosion hazard.

A

Potentialfiretrazard.

BEFORE

OPERATING

.

Gaso ine

s highlyFIAMMABLE

and

itsvaporsare

EXPLO-

slVE.

Do not

p€fmlismoklng,

open flames,

sparks or heat

rn

theareawhile handl ng

gasoline.

Avoidspilling

gasoline

on a hot engine.

Comply with all of the

aws regutaiing

storage

and

handling

of

gasol

ne.

.

Slore

gasol

ne and otherfuels

only ln containers

designed

and approved forthe

norage oi such mateials.

.

Add

gaso

in€ in a

clean, welfventlated

area. Wipe up any

spllled

gasollne

immediatey. t gasoline

has been spiled,

let ri dry

completely befo.e startirg

the engine.

.

Do not

ovedi I the luel tank. Alu/ays

alow

room for fuel

expansion ll

the tank is overfilled, the

fuel can ovedlow

onto a hot

engine and cause a FIRE or

an EXPLOSION.

.

Allow

at

lean

two

(2)

feet ofclearance on a lsides

of the

engine, even

wh le operating

it

outdoors. or

you

could

damage trie engrne.

.

Thofoughyinspecttheenqinefor ooseordamagedparts
before each use,

Do

nol usethe

eng ne

unt ladjustments

or Teparfs are

maoe.

.

Check the oll level ln

the engine

before

each use.

A

Pobntial

electricat

shock hazard.

RULESFOR SAFE OPERATION

The engine exhaust lrom

thls

ptoducl

contains

chemicals known to the Stale of Calilornia io

cause cancer,

birth d6fects, or other repro­ductive

harm.

Inspectthe engine

periodically.

Repairor replace all damaged

or defective

parts

immediately.

Inspect

fuel

system

frequently

for leaks or damage.

Repair
or replace any damaged or leaking component immediately,
Never attempt to change, alter or modit the engine fuel
slstem

in any way that might

affect safety or compliance

with

applicable codes and standards.

WHILE

OPERATING

This engine was designed and manufactured for

specific

applications-

Do not

attempt to modirythe equipment o. use

itfor any application for which it was not designed.
Generac Power Systems does not approve or authorizethe

use of these engines on

AliTe(ain

Vehicles

(ATV3),go-cads,

motorbikes, alrcraft

pfoducts, personal

watercraft, or vehi­cles intended for use in competitive events. lJse of these
engines in such applications

could

result in

property

damage,

serious

injury

(including

paralysis),

or even death.

Englne exhaust

gases

contain DEADLY

carbon

monoxide

gas-

This dangerous

gas,

lf breathed in

rufficient

concen-

trations,

can cau5e unconsciousness

or even death, Operate
this equipment only in the open air where adequate venti
lation ls available.

Do not insert any object

thrcugh the cooling slots of the

engine. You

could damage the equipmentor injure

yourself.

Do not operate the engine fanerthan ihe speed necessary
to operate the equipment. Do not

run the engine at

high

speed when not operating

the equipment,

This engine requires

an adequate flow of coo ing air for its

contrnued

proper

operation. Never

operale the equlpment

inside any room

or enclosure where the free flow ol cool-

ing air into and

outof the equipment might be obnructed.

Withoui sufficienl cooling airilow, the englne

quicklyover-

heats. damaging the engine or nearby

propefty.

Do not smoke around

the engine. Wipe up any fuel or oil

spills rmmediately.

Never leave

oily or fuelsoaked ragsaround

theengine. Keep thearea aroundthe€nglne

clean

andlree

of debrls.
Keep hands, feet, clothing, etc., awayfrom moving

parts

of

this enqine.
Never operate the engine

(a)in

the rain;(b)ln any encosed

compadment;

(c)

if

the engine speed changes;

(d)

if

the

engine spa*s;

(e)

if flame

or smoke s observed while the

engine is running,
Never work on this englne or handle

any e€ctrical device

while

standlng

in water, whie

barefoot, or

while hands

of

feet

arc wet. DANGEROUS ELECTRIC SHOCK wi I result.

SERVICE

INFORMATION

Seruice on this engine

within and atlerthe waffanty

period

can be

pedormed

byanyaulho zedservice

dealer Seruice

iechnicians arc faclorytrained and

capable oi handling all service

needs.

When conlacling an aulhor,zed service dealer aboul
pads

and service.auAys_sllBlflhclgnllgE

nodelnumberand

serialnumber oi

your

unit as

given

on ils dala

plale

decal. Seethe illlstration

below ior the location oi the decal.
The wafianty for this engine is included in the

0wners manuat.

DIMENSIONS AND fEATURES

MODfL

GTV99O

TYPE

I]LCEOLED

4-STREKE

lHV

BORE X STREKF

90 x 7A

DISPLAC

EMENT

99?cc

CBMPRESSlEN

RAT]D

8.5'1

LUBPICAIIIN

SYSTEI.l

rUI

L

PAES-UO]7'D

V/LO\"/

!I . PPE\SLPf

SI.LIIE i

IGNl IIUN

SYSTEI.I

ELICTPDNIC

SPEAKfRLESS

CYL]NDER

CAST IRDN

SLEf VL-

S

IARTING

SYSTEM

ELECTRIC START

IIL CAPACITY

C030ml V/FILTEP,

1750nl V/B

FILTER

VE]GHT

454!a€

/)]Dtbs

DIMENSIONS AND FEATURES

DIMENSIONS AND FEATURES

DIMENSIONS

AND

FEATURES

P,/N OC2965A

P/N OC2955C

P,/N

OC2965t

+CYCLE

ENGINE

THEORY

ftheengine isto

run

properly,

four

(4)

events rnustoccur in

the

proper

sequence and a!the corect time. These

events are

(a)

intake,

(b)

compression,

(c)

ignition

and

power,

and

(d)

exhaust.

A INTAKE

The

piston

is travellinq from top dead center

(IDC)

to bottom

dead center(BDC).

The

cam

has

opened the intake valve. The

piston

s

downward movementin the

cylindercreatesa

partial

vacuurn in the cylinder Air at atmosphefic

pressure

is drawn
into the cylinderthrough the carburetor and is mixed with fuel
in the ca lburetor. The fuel air mixturc flows

thrcugh the open

intake valve into the cylinder When the

piston

reaches BDC,

the intake stoke is over.

C rcNrT|oN

AND

powER

By

the time the

piston

reaches TDC , combustion is akeady

in

progress.

The intake and exhaustvalves remain

closed as the

exprnding

gases

of combustion

force

the

piston

downwad.

D

EXHAUsr

The exhauststroke

beginswhen the

piston

has

rcached BDC

and

has

started its upward movement. The intake

valve is

closed. The exhaunva ve is

open to let

gases

escape.

B

coMPREsstoN

As

the

piston

reaches

bottom de6d

center

(BDC),

both the

intake

and exhaustvalves

are closed. The

piston

moves upward

toward

TDC and

thefuel-air mixture is

compressed.lust before

the

piston

rcaches TDC, ignition

occLirs.

SECTION 1: GENERAL

INFORMATION

SECTION CONTENTS

PAGE

MATNTTNANCE SCHEDULE

.-........................-.......--.......

r-l

FUEL AND OtL RECOMMENDAT|ON5.........-..-.................

1-l

Gasoline

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

... l-l

Lubrication ..........................................................-.....

l'1

Recomrnended Oi1 Type..............................................

1'1

Chanqe Oi1..................--.............................-.-..........

1-1

Change

Oil Fi|ter..........-..--.......................-.................

1

-2

Cleaning

Intake Scr€en ...........................-.-................

1-2

Replace Spark Plugs .................................................-

1'2

Air C eaner Maintenance

.........-.....-..........................

1_3

Servlce Dual Element

Ai C1eanels..............................

1-3

TROUBLESHOOTTNG

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

1-4

5y5tematic Check ....--..................,..,,.,.......................

1-4

Check lgnition . .

. . . - . . . . . . . . . . . I

'

check lgnition

(Enqine

Running)..................................

1'

Check lqnition

(Fouled

Pluq of other Caules) ..............

1-

Cylinder

B.

anc.

TFst .......

.... l-

Cre.l Fuer ............. . ....... . .. . ...

... .....

1-

CheckCompression......................................................1_

Cylinder Leakdown

Test ..............................................

1_

Thinqs

Which Affect Both Cylinders ............................

1-

Thing! Which Aff€ct One Cy

lnder

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

1'

EQUtpI/tNr

AffEClrNG

ENGtNt OPtoATO\

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

Had Startinq orwi

NotStar'1 ............................-....... 1-

EngineWon'tstop......................................................

1-

Vibralion......................................................................

l-

PowerLoss......-...........................................................1-

Noise ..........................................................-............-..1'

NOTE 1 : Change

oil and lller aft€r ilrst 8 hours

ol operation

and

lhen

every 100

hours lhercallsr. Chang€ soonerwhen

opeEtng

under a

heary

load

or

in a dusry or dirty €nvionmenl or in hilh

ambienltemperature.

NOTE

2: Clean mor€ olien when operaling in

didy or dlsiy condillons-

Replace

canlster slyle lilter every 500 hours.

NOTE 3:

Perlorm this lask ONLY afrer lilst 50 hourc

oi op€ration. Head

bolls will NOT need

lunher rclorquing.

FUEL

AND OIt RECOMMENDATIONS

GASOL

NE:

We recommend the use

of clean, fresh lead{ree gasoline.

A rnin-

imumof 85 octane is

recornmend€d. The

use ol eadjree

gasoline

results in

fewercombustion deposits and longer valve life.

Not€: Some fuels, called

oxygenated

or refonulated

gasolines,

arc

gasolines

blended with

alcohols ot etheE.

Ex.essive

amounts of these blends can damage the luel

system

or cause

pertormance prcUem'

Do not use

gaso-

Iine

which contains Methanol. lf any undesirable

operating

swptoms occu|, use

gasoline

with a lower

pe'-

aentage

of alcohol or ethei

It is also recommended

that

gasolin€

be

purchased

in small

quantities,

notmorethan a

30daysupply. FRESH gasollne

min-

imizes

qum

deposits,

and also u/ill ensure fuel volatility

tailored

for the season

in which lhe engine willbe operated.

LUBRCATON:

Oil has four

purposes.

lt cools, ceans, seals

and lubricates.

During nornral operalion,

srnallparticles of metalfromthe

cylin

der

walk,

pistons,

bearings and

combustion

deposits will

gr:dually

contaminate

the oll. Dust

particles

from

the aLr aLso

contaminale the oil

formlng an abrasive mlxture

which can

cause

wear to al of the

nternal moving

pads

of the engine,

lf the

oilis not changed

regulary. Fresh

oilalso assists in cool'

ing. Old oilgradually

becomesthick and loses lts cooling

abi

iq/

as well as

ils lubricatlng

qualities.

RECOMMENDED

O t TYPE:

Using

the

proper

type and

weight of oil in

the crankcise is

extremely

lmportant. Checkthe oilbe{orc

each

use and change

the o

Iregularly(s€e Figures 1-1,

l-2 & 1-3).

Faiurcto

usethe

(o|ecl

o

I.

orLs:19d

-y

oi,

(dr

caJse p emarure

e19i-le

wea'

and

failure.

Use only

high

qua

ry

deterqent

oil rated

w th API s€rvice clas-

siflcatlon

SF, SG or

SH. The recommended oilwelghts

incLude

the

{olowing:

.

During summer

months: SAE 30. An accepta

ble subnitute

is sAE

10w-30. After fi6t oll

change,

syntheric o I G

1,1

MAINTENANCE SCHEDUTE

Every

lElery I

Every

I Houts 125 Hou6 50 Hours

Change OilF

ller

Spa*Plug
Clean Spark

Beloque Head Bo ls

SECTION

1: GENERAL INFORMATION

.

Durinq

winter r.onths

30. DO NOT USE SAE

SAE

5W-30, Synthetic

sW-2

0 or 5W'

10w-40.

F

-2A

a 20

40

60

30 rou

c 30

.20 .10

ro

20

30

Temperature

Fange

or Ev€cted

Us6

CHANGE

OIt:

The cra nkcase oil

capacity is

about 2030

ml

(2.

I

qt

)

with the

oilfilter Withoutthe flfter,

the

oilcapacity

is 1750

ml(1.8

qt.).

Use no special additives.

Makesur€

ihatthe

unit

is everwnen

filling

with oil. DO NOT

OVERFILL.

TMPORTANX

DO NOT

OVERF|LL.

Check

and

maintain oil

level

rcgularly.

Change oit

and fittet

aftet

fi6t eight

(8)

houts

of opetation.

Thereafter,

change oil €nd

filter

every t0O

hou6

oJ opera

tion.

Ch:nge

oil more

often il

enqine i5

operated in

dirty or

dusty

conditionsor

f€n9ine

isoperated

und€r healy

|oaos or

high ambient

a ir

temperatures.

Removeoiidrain pllg

and

drain oitwhite

€ngife

is5r wdrin,

Figure

1-2.

Chanqe

o I fllter

(Figure

t-l)and

reptace

dratn

ptuq

figurc

1-1. o

fill Check

Remove

dipnick

and refitlslow y

w

th new

oilof

proper

5€r

vr.e

classification

and viscosity grade.

R€f I

to fu mark

on

dipstick.

When

check ng

oil evet,

d ipst

ck must

be a ll the way

in

for

accurate

readtngs.

Start

and

run

engine

to check for

oil leaks.

CHANGE

O t FLTER:

Replace

oil f lter

€very I

00 hours.

Befo re nstalt

nq

new I rer,

ightly

oil filter

galket

with

fresh

clean engine oit.

Screw fiier

on by hand

until

gasket

cont.cts

filter adapter

Tighten

3/4 to

one

fullturn

fadher, Fiqure

1-3.

Startand run

engineat idle for

30 seconds and

stop engine.

Recheckoi levelandadd

if required.

Reltartengineandcheck

for

oil

leaks.

figure

1-2. OilDrcin

figure 1-3.

Oil Filter

CLIAN NG INTAKT

SCREEN]

Grass

partices,

chaffor

dirt can clog

the atrcooting

system,

especially

after

prolonqed

service ln

cLjtting dry

grass

or v€ry

driry a r.

Continued

operation with

a cogged

cooling

synem

can

cause severe

overheat ng

and

possible

englne

damage.

Fgure

1 4showsth€arcastobecieaned.Thisshoutdbea

reg-

uar marntenance

operation, or

clean ntake scre€n

and ol

cooler

fins after

each use.

1-2

SECIION

1:

GENERAL

INFORMATION

REPLACE SPARK PLUGS:

Replace

spark

plugs

every 100 hours

of operation or every

season, whichever

occurs first. Replace

spark

plugs

if elec,

trodes are burned

away, orthe

porcelain

is cracked. Setspark

plug gap

at.76

mm

(.030')

for

all models. Torquespark

plugs

to 20.0

Nm

(180

in. ibs_).

Figute 1

-5.

Setting

Spatk

Plug cap

tions are

notcarcfully

followed,

dirtand

dun which

should be

collected in the cleaner, will

be drawn

into

the engine. These

particles

are

highlyabrasive

and willcausethe

plston

rings and

cylinder bore to wear

quickly.

As

the

rings and

cytlnder bore

become worn, these

abrasive

particles

enter

the crankcase

and

contaminate the oil, forming

an abrasive

mixture which

willcause wear

on allof the internal

moving

pads.

The air cleaner on every

engine brcught

in for

a check up

or repair should

be examined and

seNiced. tf

the arr ceaner

shows

signs of

neglect,

show ittothe

customef

berore oean-

ing. Instruct the customer

on

proper

care, to assure long

engine life.

Note: Repla.e ai .leaner

gaskets

and mounting gaskets

that afe wom of damaged. to

prcvent

dirt and dust frcm

entering engine due to imryoper

sealing.

Replace

bent

air

cleaner mounting bracket

if necessary,

SERVICE DUAL

ELEMENTAIR CLEANERS:

Remove and service foam

pre-c

eanerevery

25 hours

orevery

season, wh ichever

occurs firn.setuice

canridge every

50 hou6

or ev€ry

season, whichever occurs first.

SERVCE CAN STER AIR

CLEANERS:

Clean the air filter elemen(s)with

compressed

air every

50

hours or every season, whichever

occurs first.

Replace

the air

{ilter elementG) every 500 hou6

or if damaged.

Note:

The air cleanet assemblies

on some

equipment

may have been supplied by

the equipment

manufa.-

turei

See the equipment manufadurels

owne/s

manual

for seNi.e infomation specili.

to that

prcduct,

TROUBTESHOOTING

lvost compaints

concerning englne

operation

can be clas-

sified as one or a

combination ofthe

followlngi

2. Hard starting

3. Lack ol

power

4. Runs rough

GENERAC

C h

Spark Pluq Type Part

No.

Resistor Plug

AIR CLEANER MANTENANCE:

Vrbration
Overheating

High

oi consumption

472341

RC t2YC

5.

6.

1.

WARNING:

NEVER OPERATE

ENGINE

WITH AIR

CLEANER

ASSEMELY OR

AIR CLEANER

CARTRIDGE

REMOVED.

FIRE MAY RESULT.

A

properly

5erviced air cleaner

protects

lnternalpa(s

of the

enginefrom

dlrtand dun

pa.tic

es in

the air lf aircleaner instruc-

Note: What appears

to be an engine malfunction

may be

a fault of the

powercd

equipment Bthet

than the

engine.

lf equipment is susped,

see equipment

atlecting

engine

Figurc

1-4, Clean lnhke

Sqeen & Oil Coolet Fins

SET PLUG

GAP AT 0.76

mm

t-3

SECTION

.I:

GENERAL INFORMATION

SYSTEMATIC CHECKi

lf the engine will not stad

and the cause

of malfuncrion is

not €adilyapparen!

perform

a systematic

check in the fo lowing

orderl

1. lgnition

2. Fuel

3. Compression
This

check'up,

performed

in

a systematic manneri

cdn usu-

ally be done

in

a matter of minutes.

lt isthe

quickest

and surest

method of determining

the cause of fiilure.

The basiccheckup

procedure

isthe same

for all engine modeh,

while

any

varia-

tion, by model, wiilbe

shown underthe

subject heading.

CHECK IGNITION:

lf spark does not

occur look for:

.

Shorted ignition,kill

wlre

.

Two cosed

diodes in

ground

wire harness

.

Incorrect

a rmature

air

gap

FIECK

lGNnoN

{ENG NE RUNNING)I

ifengine

runs but misses

during

operation. a

quick

check to

determine if

ignition

is or is not

at fault

can be made by

installing

a spa*

tesler

(Generac

p,t\l

OC5969)

between the

spark

plug

lead

and each

spark

plug,

Figure t-6.

A spark mks

will be

rcadily

apparent

when the

engine is running. tf spark

i5

good

but

engine

misses, check

for a fouled

spark

plL'lg.

CHECK ]GNITION

(FOULED

PLUG OR OTHER

CAUSES):

To

check for a fouled spark

plug

or a nonjunctioning

cylin-

der. attach

the

lpark

tener

(Generac

P/N

OC5969)between

the

spark

plug

lead

and each spark

plug.

Stad and run

engine at

top no lo.d

speed. Now

ground

one spark

plug,

Fig! re t

-7.

The

engineshould

continue to run on the

other cylinder Repeatthis

test with the other

cylnder lf the engine

will not continue

to

run when making

thistest, the

cylinder that ls NOT

grounded

is not functioning

and/orthe

spark

plug

is fouled.

Installa new

spa*

plug

before

prcceeding.

f miss

cont n!es,

problem

may

be carburetion

orcompression. See

Check Calburction,

Check

Compression.

Also see Cy inder

BalanceTest.

Figvre

1-7. Checking

fot Fouled

plugs

CYL NDER EAIANCE TEST

lf the

enqine is hard stadinq,

runs rough,

misses or tacks

power, pertorm

a cylinder

balance test

to determirre

wnerner

boih

cylirdes are ope.ai 19

rc trerr fL lporenlrat.

Tools Requircdi

1. Two

gnition

Teste6

(Cenerac

P/N

OC5969)

Attach

an i9nition

tester betwe€n

the spark

plug

lead

and

each

spark

plug,

Fiqure

1'6.

Stadand run

engine runnln9

attop no load

speed and note

spark at ign

lion teste6. lf the

spa.k is equat

at both

jgniUon

testers,

the

problem

is not igniton

related.

A spark miss

will

be readily apparent. Now

note RPM

of engine. Ground

out one

cylinder by

contacting ignition

tester and a

good grcund

on

engrne, Figufel

8. Note RPM loss.

Then

ground

out the

other

spark

p

ug and note ihe RPNI

loss. lf the difference between

the two cylind€rs does not

exceed 75 RPNI, the amount

ofwork

the two

qlinde|s

are doing should be considered

equal.

figwe

1-6. Running

Check

J'

I

I

I

SECTION 1: GENERAL INFORMATION

I

lfthe RPw

loss isgrcaterthan 75 RPIV this

indicates that the

grcunded

cylinder

with the least RPM loss is the

weakest ot

the two cylinders.

Look to th.t

qlinderfora problem.

Example:

Engine RPM

-

Both cylinders = 3400 RPM

Engine RPM - #1 Cylindet Grcunded

=

3300 RPM

Engine

RPIV - *2 Cylinder Grounded

=

3100 RPM

Conclusion:#1

cyllnder is weakest of the two cylinders.

EXA[4PLE:

cyl. #1

cyl. #2 Diff.

Eng. +l

165 PSI

160 Psl 5 Psl

Eng.42 175

PSI 155 PSI 20 Psl

lf

compression

is

poor,

look for:

.

lnsufficient

valve clearance

.

Loose cyllnder

head bolts

.

Blown

head

gasket

.

Bumed va

ve5, valve seats and/or

loose

valve seats

.

warped

cylinder

head

.

warped

valve stems

.

Worn bofe and/or

rings

.

BDken

conneding

rods

CYLINDER

LEAKDOWN

TESI

A cylinder

leakdown tener

may be used to test the sealing

capability

of the compression

components of each cllinderand

quickly

identit the

prcblem

cornponent.

THINGS WHIC]]

AFFEEI-EO]ILIILNDIB!

l. Carburetion

2. Crankcase

vacuum

3.

lgnition timing

a.

A

partially

sheared

fl)4rvheelkey willeffect

ignition iimlng

and engine

Peaformance.

TH]NGS

WHIC H AFFECT

ONE CYL NDE R:

1. Spark

plug

a.

a fouled 5park

plug

may indicate that carburetor

is out

of adjustment.

2. Leak in spark

plug

wire

3. Head

gasket

4. lntake

manifod

a. A leak ateiiherend

ofthe

intake maoifold wlllonly affecl

one cylinder,

not both.

5.

Valves

6. RLngs

8. Cylinder
NOTE: A twin cylindet

engine

wi runwe ononecylin-

der as long as the

power

rcquircd

for the appli.ation does

not exceed the

powet

produced

by the one cylinder

Figwe |

-8.

Cylindet Salan.e Test

The cy

inder balance |en willa so detect a

qlinderthat

is not

functloning.

When

grcunding

out one cylinder thete

wil be

no

RPIV loss. When the other

qlinder

ls

grounded

out the

enqine

willsiop-

The fuel

prcssurc

can be checked using a

pressure

tester

kit

(Generac

P/N OC7977).

This kt comes with an lntormatve

'How

To' video.

CHECK COIVPRES5 ON:

lt

has

be€n

determlnedthrolghtestinq that a simple.nd

accu

rate indication of comprcssion

can be made as

fo lows:

Remove both spark

plugs

and nsert a compresslon

gaugeinto

either cylinder

(one

cylinder at a tirne).

Turn

efglne

over wilh

engine starter

until there is no further ncrease

in

pressure.

Record this reading.

Rep€ai

pfocedure

on olher cylirder

and

rccord

that reading.

The d Ifefence beiween both cy inde6

shouldnoiexceed25%.

Morcthan25% indicates ossof com-

press

on

in

the.ylinder

wth lower

presslre.

see examp

e.

1-5

SECTION

1:

6ENERAL

INFORMATION

EQUIPMENT

AFFECTING

ENGINE

OPERATION

Frequently,

whatappearsto

bea

problemwith

engine

oper-

ation,

such as

hard starting,

vibration,

etc., may

be the fault

of the

equipment

powered

rather than

the engine

itself. Listed

aA

the most

common

effects of equipment

problems'

and wilat

to

look

forasthe most

common

cause.

HARD

STARTING

OR WILL

NOT STARI

1 . Loose

belt

-

a loose belt

like a

loose blade can cause

a back-

lash

effec-t,

which wllcounteract

engine cranking

effort

2.

starting

under

load - see

i{ the unit

is disengaged

when

engine

is started;or

ifengaged,

should not

have a heavy

starting

load-

3. Check

remote

control

assembly

for

proper

adjustment-

4. Check

interlock

system

for shorted

wires, loose or corrcded

connections,

or

defective modules

or switches

ENG

INI WON'T

STOP:

1. Check

equipment

ignition stop

swjtch.

2. Check

for loose or

disconnected

equipment stop

swtcn

3-

check

ground

wire harness

on engrne.

a.

See Section

2 for test

Procedure,

V]BRATION:

1 .

Unit load out

of balance

-

remove and

balance.

2. Mounting

bolts loose

-

ughten.

r0wEe!05t

1 .

Bind or drag in unit-

if

possible,

disengage

engine

and oper-

ate unit

manuallyto feelforany

binding action

2. Unit load

ha5 excess dtag-

xol5E

1 . Engine coupling or

pulley

-

an oversize

or

worn couphng

can result in knocking,

usually under

acceleration.

Check

for fit or tightness.

2. Equipment

needs lub cation.

SECTION 2:

IGNITION

SECTION CONTENTS

PAGE

sPEClFlCATIONS..................

-..... --------------....-....

2-1

GENERAL

lNFORMAT|ON..... ...........................................

2-1

ARMATURES

Armatur€Testing................-.....................----..-.........2l

Removing

Amatures ........................-.......................

2_1

lnstall

Armatures -................ .....................................-.

2-1

Adjusi Armaturc Air Gap ..........................................

2-2

FL\1/VHEEL

Remove Flywheel ..-...................................-...............2_2

lnspect Flylvheel

Key and Keylv ays ...........-................

2"2

lnstallFlylvhee1..........................................................2_3

ENGTNE

WtRTNG HARNESS .....................-......................

2-3

Tesling Grcund Wircs............................................-...

2-3

Engine wirlng Harness Diagram

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

2-4

Diode Failurc Diagnosis

...-.--.....................................

2-4

SPECIFICATIONS

FOR

GW-990/760

0HVt V-TW|N ENGINE

MODEL 5ERLE5 ................................................Gry-990t60

ARMATURE AIR GAP.....................................008',

TO .012'

(.20TO.30

MM)

FLYWHEEL NUI TORQUE

n: 185..........--......................

..

.. - - .......150

FL\1/VHEEL NUT TORQUE

NM............__.......................................-......................203.0

See Section

1 For Spatk PIug MainFnan.e

And Spe<ifi<ations

GENERAL INFORMATION

Generac

GTV-990,60 OHVIV-Twin

engines use a

magneto

ignltionr an

ignition amalure with a

seli-contalned transistor

module

(no

moving

paats).

Two magneto

ignition arrnatures

are used, with a flyljvheel

containing a

permanent

magnet.

NOTE:

fhe magneto ignition

synem rcquires a minimum

of 350

RPM to

ptoduce

a consistent

spa*.

ARMATURES

ARMATURE TESTING:

The condition

of lhe ignition armatures

can be accu€tely

diag'

nosed using

an ignition testet,

(Generac

P/N 0C5969) as

desc bed in

'Trcubleshoot

n9' in Section

1.

REMOV NG

ARMATURES:

1.

Remove spark

plug

leads.

2.

Remove intake manifod

and covel

intake

pofts.

3. Remove rotating

screen

and blower housing.

4. Remove

armature screws and lift off armature(s),

Figure 2-1.

a. Disconnect

stop swltch

wires

at armatures.

Note:The

flwheel does

not need to be rcmoved to ser-

vice ignition

except

to check the flwheel ket.

INSTATL

ARMATURES:

1- Turn

fylvheelso magnet

is away frcm amatur€.

2. Install

ground

wire onto tab terminalon armature.

Note:

Make sure wires

are routed over afinature mount-

ing

posB

and away

lrcm flwheel.

figute

2-2. Ins|.jrlling Anaturc

3.

Assembe armature

to engine,

Figurc 2-2.

a.

Mounting holes in armature

are slotted, Push armature

away from

fly\,vheel as far as

possible

and tighten one sc€w

to hold afmaturc

in

place.

Figurc

2-1. Renoving Amature

2-1

SECTION

2: IGNITION

4. Repeatfor

second

armature.

5. Adjust

armature air

gap.

ADIUST

ARMATUREAR GAP:

1.

Rotate fl!

rheel until magnet is underamatur€ laminalions.

2. Place thickness

9au9e,

.008 "

-.012

"

(0.20-.30

mm)

between

magnet

and armature

laminaiions, Fgurc 2-3

3.

Loosen

mounting screw so

magnet

will

pull

armature down

against thickness

gauge.

a.

Torque scrcws to

12.2 Nm

(9

Jt. lbs.).

4, Rotate

flylvheel to remove thlckness

gauge,

5. Repeatfor

second armatule-

Note:

Route amature

grcund

wire

over breather tube

and

away from the

flwheel.

Figurc 2-4, Remouing FIWheel Nut

Caution: Flywheel

pulle.bolts

may damage lighting

coilif turned

in

too

{ar.

cautionr Do NoT strike llywheel

with a hard objed
or a m€tal tool as this may Guse flywheelto shat­ter in operation. Always use approved flyl/vheel

Figure 2"5. Renoving Fl@heel

INSPECT FLYIVHEEL KEY KEWVAYS. FLYIVHEELAND
CRANKSHAFT:

Check

flywheel key for

damage. Check

fly\,vheel{or

cracks

or keluay danrage. Also check crankshaft

keylvays and

taper

for damage, Figure 2-6. Repace crankshaft,

if damaged.

A
A

FLYWHEEL

RE[,4OVE

FLY]/VHEEL:

1. Remove

fllavheelnut and washer, Figure 2-4.

2. Remove

fan retainer and fan.

4. Reinstall

flywheel nut. Turn nut down flush with top of

mrea05.

5. Install fllu/heeT

puller

6. Tighten

puller

screws equaly untll fly\,vheel loosens.

Figure

2,5.

Figurc 2-3, Adjusting

ai

Gap

2-2

SECTION 2: IGNITION

Figue 2-6, Che.k

Hwheel And eankshaft

INSTALL FL\ryVHEEL:

Note: CLEAN flwheel

and

(ankshaft

taper removing

all

oil, dirt or

gtease.

1.

Insertflylvheel key into crankshaft.

2. Align

keyways and assernble flylvheel to crankshaft.

3. Installwasher and

flylvheel nut.

a. Toque fly,vl/heelnut to

203.0 Nm

(150

ft.lbs.),

Fiqure 2-7.

4. as5emblefan and retainerto

flywheel, Figure 2 8.

a.Torque screws to

2l.7 Nm

(192ln.

lbs.).

Figure 2-7,

Totquing Flwheel Nut

Figurc 2-S.lnsta ing Flywheel And

Fan

ENGINE KILL WIRES

The

engine

kill wires conslst of a

grcund

wire with a diodefor

each armatureand

a separate wire for the carbu retor solenoLd.

The engine killwires are connected

to the wirlng harness

pro-

vided by the equipment manulacturer

See engine

wire diagram,

Page 6-3.

TESTiNG GROUND WIRES:

Use a

Digital Multimeter

(Figure

2-9) to test the

ground

wires.

The iollowing test w

llbe made with the meter in the Diode Ten

In the Diode

Test

position,

the meter will display the foftvard

voltage drop acrcssthe

diode(s). lf the voltage drop is less than

0.7

volts, the meter will ' Beep' once as

well

as display the

volt-

age drop. A continuous

tone indicates continuity(shoned diode)

An incomplete circuit

(open

diode) will be displayed as

'OL. '

2.3

Figurc 10. Digital Multinetel

SECTION 2: IGNITION

'L

tnsed

RED test lead

into

yo+

receptacle

in meter.

2. Insen

ELqCK

ten lead

intothe.,COM.

re.eptacle

In

meter

3.

Rotate

selector

to

>i n t (Diode

Test) posttio,r

4. hsert

RED test

lead

clip into

connector

.

A'

(Fiqure

2_ I

0).

Leave

attached

for

femainder

of test.

5. Touch BLACK

ten lead

probe

to terminat

,8.,,

a.lf meter

'Beeps'

once,

diode

is OK.

b.lf meter

makes:

continuoLrs

tone,

diode is

defective

Ghorted).

Replrce

ground

harness.

c. lf meter

displays

'OL,'

diod€

is defective (open).

Replace

ground

harness.

6. Now

repeat

test for

terminal

,

C, , Results

must

be

the same.

See

"Diode

Failwe

Diagnosis-

betow

SPARK

PLUG

SPARK

PLUG

DIODE

figute

2-11.

lgnition

Whing

Hamess

DIODE

FAITURE

DIAGNOSIS

IGNITION

KILLWIRE

ENGINE
GBOUND
HARNESS

POSITIVE

Ii4ETEB

TEST

LEAD

NEGATIVE

I\4ETER

Figurc

2-10. Testing

Grcund

Whe

GROUND
WIRE
HARNESS

SWITCH

ON

TURNED

OFF

CAUSE

Engine

Runs

On I

Cy/jnder

shuts

off oK

I

Closed

Diode

Engine

Runs

(Both

Cylinders)

OnIy

One

Cylinder

shuts

Off

I

Open Diode

(No

Spark)

2 Closed

Diodes

Engine

RLins

(Both

Cylinders)

Engine

Won t

Shut

Off

2 Open

Drodes

2-4

SECTIOl'l

3: CARBURETTON

SEcTION

CONTENTS

PAGE

caRBURETOR

rypES

_......_....................__.......................

3_1

cARBURETOR

RENrOVAr............_....._..............._.._........_.

3_.1

cLEANtNG

CARBURETOR

................._._........_................_

3_1

cARBURETOR

tN5TA11AT|ON

................_........_..............

3_1

STATTC

GOVERNOR

ADJUSTMENT....._.............._.............

3-2

FUELPUIiTP.-.......................-................................__.......3_3

CARBURETOR

TYPES

There

are four

types of

carburetors

used

on

Cenerac

aHVl

V-twin

engines:

1-

Keihjn

hr',7o,barrel,

side-drafton

Models

EVI-04198-0,

EVI_

04629-0,

EVr-04629-1,

EVT_04630_0,

EV\-A47

41

-0,

EW-04772.0,

EW

a797.A.

0aao7

-o.

04861_0,

oD3l58.

0E0038.

2. Denitwo-barrel,

side draft

on N,4odels

EW_4174_0,

04198-

1, 04629-2,

04806

A,083342.

3. Nikkr

two-barrel,

side-draft

on N,4odeh

EW-04712-0,

EW_

047 17-O,

A4717-1,

EVT_04739_0,

04857_0,

04858,0,

04862-0,

0D7675,

0D9033.

4.

Nikki

sin9le,barrct,

side-drafr

on Ntodet

0D9708.

CARBURETOR

R€MOVAL.

VERTICAL

SHAFT

(lvodels

EW04629-0,

FW.A4629-1,

04629-2,

EW_OA1

fi

-A,

o47 17

-1

,

EW-04797

-0,

04A06_0,

04857-0,

04858,0,

04862_0,

0486r-0)

1.

Unclip

choke link

from

bellcrank

and remove

link from

carburetor.

2. Disconnect

fuefshutoffsotenoid

by unboking

the

ground

w;e fro-

the mar

lotd.

ard unptJgg

rq

the

po*e,wrre

Note:

Wires

simply

unplugfromthe

solenoid

on

modets

04629-2,

EW-04717-0.

04717-1,

04A06-0,

04A57-0,

O4a5&

0, &

04a62-O.

3. Disconnect

breather

tube.

4.

separateihrottle

link

balljointfiom

carburetor

oy rorar

ng

the ballsocket_

5. Disconnect

the fuel

line.

6. Removethe

fournuts

holding

the carburetorand plenum

to

the intake

manifold.

7.

Remove

the

plenurn,

carburetor,

and

gaskets

from

the

manifold,

and

discard the

gaskets.

Figurc3"2.

CLEANING

CARBURETOR

tor cleaning purposes,

the carbufetor's

float

bowr

may

De

removed.lt

is recommended

that

alljetting

be left in

ptace

whte

clean

ng the

carburetor

Be sure

to use

a cleaner

that

won,t

damage

rubber,

neoprene,

or

plastc

parts.

lf the fuel

shutoff

solenoid

is suspected

of

being

fautty.

it is

replaceable

bysimply

unthreading

it

from

$e float

bowt,

and

installing

a new

one in

its

place.

tt

can

be checked

by appty-

ing

12 vots

to it. tf

you

hear it

click, it

is most

likety

working

properly.

lf

there ls

anyth n9

etse wrong

with

the

carburetor,

r rs recommen

ded

that

lhe entirc

caburetor

b€ replaced

with

Figurc3-1,

3-1

SECTION

3: CARBURETION

CARBURETOR

INSTATI.ATION

-

VERTICAT

SHAFT

(Models

EW

04629,0,

EW-A462?

t,

A4629_2,

EVI 041

17

_A,

04111-1,

EW-04791

0,

a4806-0,

048s7-0,

04858,0,

04862-0,

0486r-0)

1.

Sirde new

carburetor

gasket

onro

th€

nuds.

2. Slide

the

carbur€toronto

th€

nuds.

3.

Slide new

plenum

gasket

onto

th€

studs.

4.

Slide

the

ptenum

onto

the

nuds.

5. nnall

the nuts

on

the four

studs,

and

torque

to 4 it

b5..

6.

Connect

the fue

line.

7.

Using

a

pirels,

reassembte

the

ba

joint

on ihe

carbureto.

8. Connect

ihe

breather

tube.

9. Connect

the

fuet-shutoff

sotenoid.

rigurc3-3.

10.

R€lnstallchoke

ink

in

carburetorand

ctip the hfk

Into

the

I1.

Perform

a

stai/c

goverfor

adjustment.

12.

Stair

engife

and

a

ow

to w.rm

up

for

_5

min

13.

Move

speed

contro

everto

slow

spe€d

position

an.tho

d

throttle

ever

against

idte

stop

screw

14.

adjust

stop

screw

to maintain

_t2O0

RpM idte.

15.5ow,y -pv,.

p..p6

s6nt

or

'e/er

oro,sob6doo,.or.

Do

nol

exce€d

4000

RPN,1

Figute

3-4.

Note:

The.high

speed

sc.ew

may

need

adjusting

to rcach

tne

speed.ontrct

stop

without

ex.eeding

4OOO

RpM.

l6

rL\

''h

rfa.pepd

Lolt ot r

I,r" rrgh

sp"ed

po.

-ior,

a4 ,n

rl o hrgt

sp-Fd

sc,er ro

ob-air

ll

e d".r.ed

e.lgtne

speeo.

STATIC

GOVERNOR

ADJUSTMENT

Loosen

the

c|nch

ng screw

on

the

qovernor

lever

flold governor

levef

tn

WOT

positon

and

rotare

the

gov,

ernor

afm

ctocKwrse.

While

liolding

thE

positon,

re torque

the c inchir

9

scr€w

to

100 in

lb

Ch€ck

to

make

sur€ that

rhe

throtte

rravetsfrom

wOTto

idle.

lf it

doesnl,

the

qovernor

needs

to be

resel

agarn

t.

2

3.

3-2

SECTION

3: CARBURETTON

FUEL

PUMP

rlte

fuel

pump

supptied

witn

the

engines

is

a

pJhe

pump

I uses

crankcase

vicuJn pulses

ddwn lrom

tl-e valve

(over

of cylinder

#2

to

pump

the fuel.

tt is

capable

of

pfiming

at

'12'(30.5

cm)max

lift.

The

pump

has

a rrax

ouu€t pressure

of ] 5

psi.

lf a fuel pump

other

than

the

one

described

above

rs

used,

the fuel

line

pressure

at

the

carburetor

inlet

must

not

exceed

3

psi,

Pressures

in

excess

of

3

psimaycause

an

over rich

caF

buretor

mfture

thatwould

lead

to engine

damaqe.

Figute

3-6.

Fuel

33

NOTES

#p

q:ffi

34

SECTION 4: GOVERNOR CONTROLS AND

GOVERNOR

f€*

r.qrf,i EF",;

4:llji

SEcrlON CONTENTS

PAGE

MECHANTCAL

GOVERNOR ........................................... 4 1

GOVERNOR..._..............................................................4-1

GOVERNOR ARM

.......................................................... 4-1

STATIC GOVERNOR ADJUSTMENT ................................ 4-1

DYNAMTC GOVERNOR ADJUSTMENT ......................._.. 4-2

MECHANICAL GOVERNOR

DISASSEf,,IBLE:

1. Drain the oilfrom

the engine.

2. Remove any rust, nicks, or burrs frcm the crankshaft.

3. Remove

the 4 oil cooler scrcws,

4. Disconned the wia n9 from the oil

pressure

switch-

5. Remove the

governor

lev€r ircm th€ shaft.

6.

Separate the balljoint on the swinqing arm.

7. Remove allofthe crankcase bolts and sllde the crankcase

Note: Watd,

the swinging atm bftcket so that it doesn't

hook on the sheet metal.

8. Discard the crankcase

gasket

& oil

passage

seal.

GOVERNOR

Eoth the

spooland the flyweiqhts

must move

freelyfor the

governor

to

work

properly.

Check

for

wear on the spool and

flyweights. lf wear is noiiced, change the

governor gear

assembly

(gear

and flyweights),

spool,

and

governor

arm.

Lub

cate all

moving

parts

when

reasserabling.

1. Force

gear

assembly and

governor

spool

off of

governor

shaft.

2. Remove any remainlng

plastic

from the notch in

the

gov-

ernor 5nan.

3. Checkthat allthe

governor

bearing

pans (top

pLile,

oear-

ing,

and bottom

plate)arc

ontheshafi, andthat

! moves

4. Slidethe newgear assemblyand

spoolontothe

governor

shaft. Sllde u

ntil

the

gear

hooks into the notch in

the

gov-

GOVERNOR ARM

lf the

governorarm

does not move frcely,

or ifthe arrn feeh

loose inthe

bushings,

itmay need

rcplacing. lf wea r is notlced,

change the

govdrnor

arm,

governor gear

assembly

(gear

and

flyweights), spool. and bushinqs as needed.

Lubricate all

moving

parts

when reassembling.

1. Remove the e-clips.

2. Sl d€ the arm down and out of the bushings.

3.

Replace any

parts

that appear worn,

Note: The lower

bushing is

a slip fit, and

the upper bush"

4.

Slide the

thrust washer

part

way

onto the new

governor

5. Insert the

governoa

arm in the lower

bushing hoder,

and

slid€

it

pair

way in.

6.

InstaLl

ower e-clip onthearm, ands ide the

thrust washer

7. Slip the lower

bushing

par!

way

on to the

afm.

Figure 4-2. Govenot Arm Assembly

Figure 4-1. Govemot Geat Assenbly

and Spool

SECTION

4:

GOVERNOR

CONTROLS

AND GOVERNOR

8. Slide the arm

in until the thrust washer is tight.

9. slidethelowerbushingdownand

intoitSholder,theninsirll

the upper e-clip.

ASSEMELE:

1. Clean any old

gasket

material from the crankcase

and

cover mating sudaces.

2.

Be sure thal the new oilpassage

o-ring is in

place.

3.

Put a

new

gasket

on the crankcase,

4. Slidethe

crankcase cover back on the crankcase.

Nol€:

Hold the

govemor

atm in

the counter-clo*wise

position

wlrile insta ing, Also, nldke

surc thatthe swing'

ing

an bhcket

goes

in

place.

5. Stan all of the crankcase

bolts, and then torque them to

35 ft.

lbs., following the

propertorque

sequence.

STATIC GOVERNOR ADIUSTMENT

Loosen the clinching

screw

on the

govemor

lever

Rotate

the

governor

arm clockwise and hold

governor

lever

in WOT

position.

While holding this

position,

torque the clinching screw to

11.6 Nm

(100

in.

Ibs.).

Check

to make sure that the throttle

travels from WOT to

idle.

lf it doesn't, the

governor

needs to be resetagain.

Figurc 4-5. Dynamic Govenor Adjustment

DYNAMIC GOVERNOR ADJUSTMENT

Slart engine and

a'bw 10 warr up fo 5 mi,rures.

Move speed

control lever to dowspeed

position

and hold

thrcttle

lever against idle nop scfew

1.

2.

L

TOROUE

SEQUENCE FOR

CRANKCASE

COVEF :

1

-2-3-4-5-6-7-8-9-

1

0

Figurc 4-3,

5. Reconnect the ball

joint

on the swinq arm.

7- Place the

govenor

lever on the

governor

arm,

with the

spring in the 4th hole out.

8.

Perform a static

governor

adjustment.

9. Reconnectthe

ground

wire to the oilpressu€

switch.

10. Reattach the oil cooler to

Ihe blower

housing

t.

2.

Figurc 4-4, Sati. Gowmot Adjustnent

SECTION 4:

GOVERNOR

CONTROLS AND GOVERNOR

3. Adjust stop screw to maintaln 1200 RPM idle

4.

slowly

move

speed control lever to high-speed

position.

Do not exceed 4000 RPM.

Nol€: The high-speed

screw may need adjusting to rcach

the

speed .ontrol stop without exceeding 4000 RPM.

5. Wth the speed controljn the high-speed

position,

adjust

the high-speed

screw io obiain the desired engine speed.

Figurc 4-5.

Dynamic Govenot Adjustnent

4-3

NOTES

SECTION 5: CYLINDER HEAD AND VALVES

*-w1;

rYffi B&';

*jF-r

SECflON CONTENTS

PAGE

GENERAL tNFORMATON ............................................... 5-1

REMOVE CYLTNDER HEAD5................................-........... 5,1

Remove Rocker Arms ................................................ 5-2

DtSASSEMBLE CYLTNDER

HEA0......................................

5-2

tNSPECT AND REPAIR .......................'-.'-....'...................

5-3

Reface valves

and Seals

...................-............,...........

5-3

aSSEMBLE CYLTNDER HEAD.......................................... 5-4

tNSTALL

CYLTNDER

HEAD ........... ...,_...'-.......'................

5-5

aDJUST VALVE

CLEARANCE

....... ....._............................ 5-5

REASsEMBLE .............._............._...................................5-5

STAT|C GOVERNOR

A01UsTMENT................._._.........._... 5-6

GENERAL INFORMATION

compression testlng information and

procedu

res is descrlbed

Cylnders are numbered as shown in Fgure 5-1.

Figurc 5-1.

REMOVE CYLINDER HEADS

D sconnect exhaust systemfrom exhaust manifold. Remove
exhaust manifold faom englne. D sconnectchoke and throttle
control cables Remove spa* p ugs.

1. Removelhe

parts

depicted in Figure 5-2.

a.

Discard

gaskets

and

valve

cover seals.

@

rncen cuano

@

nornrruo scneeru

@

rrre<e

unurroro

ASSEMBLY

@

orr coorrn

@
@

BLOWER HOUSING

@

rowen wneceen

@

varve coven

Figurc *2.

5-1

r

SECTION 5: CYLINDER

HEAD AND VALVES

Note:

Ma* components

so that

they may be

rcassem-

bled in theh ofiginal

position.

RE\,IOVE

ROCKER ARN,45:

1.

Ljnlockjam

nutsand rcmovetwo

ballstuds

and rocker

arm

assembJiet(see

Figure

5-3).

2. Remove

push

rods

and identify

each.

Note: The

valve

push

rods

arc aluminum,

Matk

push

rods for

identification

to

Nevent

interchanging.

,/

BALL STUD

6tr ,FOCKEB

AR/\,l

,xa;g JAM NU'r

Figure

S-3.

3. Remove head

bolts and cylinder

head

(Figure

5-4).

a. Discard

gasket.

4. Repeat

Steps 1-3 for

other cylinder head.

DISASSEMBTE

CYLINDER

HEADS

I Piace

a shop rag orshort section

of rubberfuelline

under

valves

inside combunion

chamber

to hold valve in

ptace

while

conrpressing sprlng.

2.

lold down valve

spr

ng

retainer

by hand or with a vatve

spflng

compressor

(Figure

5-5).

Remove

the following:

a. Valve

spring keepers
b.Valve spring retalner
c. V:lve sprlng
d.lN

and EX valves

3. Remove and discard valve

stem

seals

(Frgure

5,6).

Figurc

5-5. Renoving Retaine9

Figurc 5-4.

henove Cylindet

Head

Figute

,6. Rei/loving

Valve Sten Seals

SECTION

5:

CYLINDER

HEAD

AND VALvEs

INSPEO

AND REPAIR

I

Check

cylinder head

(Figure

5-7). Be

sure allgasket

mate_

rialis

rernoved from

sudaces

before

checking.

Use d gasKer

scraper f necessary

a.Inspect

cylinder head for.r€cks

or damage.

b. Use

a sudace

plate

or straightedge

and check

q

inderhead

mounUng

sudace

for

distortion.

lf

mounting

surfaces

are distoned

more

than

.004"

(0.1

mm),

the

cylnder head

nrust be

replaced.

Note:

lt is not

fecommended

that cytinder

heao

moun.-

ing

surtaes

be rcsuiaced.

Figute

5-7. check

Cytindet

Head

Distottion

2.

Clean

thevalve

gu

des

and measurethe

r l.D.

lsing a sptit

ball

bore

gauge (Figure

5,8)

a. Replace head

if either

valve

guide

measures

7.06

mm

(0.278

in.)

or more.

REFACE VALVES

AND

SEATS:

1. Va lve

seats may

be reconditioned

using

a valve

seai

cutter

lf valve

seat k widerthan

dimensjon

shown

in Figure

5-9, a

narrcwing

cutter

should

be used to

ensure

that conEcr

area

of

valve

seat is

centered

on face

of valve

(Figure

5-tO)

a. use

a 60" cutter

to narrow

seat from

bottom

and

a i5.

cutterto narrow

seat from

top

(Figure

5-9).

Note: fi

valve seat

is loose

or uacked,

rcpla.e

cytinder

60'CUTTEF

15'CUTTER

Figurc

5-9.

Valve Seat

Dinensions

2. Valve

faces may

be resudaced

to

45..

See Figure

5_10 for

diraensions ior

valves.

3. Lap valves

and seats

with a valve

lapping

toot

ano valve

lapping

compound.

Note:

ln most

instances

it is morc

economi.at

to reptace

the valves than

to refa@

them,

r

T

Figute

5-10. Valve

Dinensions

4. Measure valve

stem

diarneier

at specified

distance

frcm

end

ofvalve,

as shown

n Figure

5 11.

Replace

if less

than 6_9 mm

(0.272

inchet,

or if

total cleaF

ance between

valve stem

and valve

gu

de

exceeds

O_12

mnr

(0.0047

in)

Figwe

5-8. Check

valve

guides

53

SECTION 5: CYLINDER

HEAD AND VALVES

2. nndllvalves

(Figure

5- 14).

Note: Lightly coat

valve stems with oil or Sped'a Lube

Red beforc insta ing

valves. Be surc lub cant is noton

valve fa.e, seat or

end of valve sten.

Figurc 5"11. Measurc Valve SteI,

Dianetel

5.

Check valve springs

for free lenqth

(Figure

5-12).

Replace lf

free length s ess than 36.5 mm

(1.437

lnchet.

Figurc 5-14. lnstall Valves

Place a shop

rag or shod section oi rubber fue ne under

valves

ins

de cornbustion

chamber to hod va ve in

place

while compressing

sp.ing.

lnna I va ve springs and

valve

sprinq

retalners

over

valve

Figure 5-12. Check Valve Spings

ASSEMBLE CYLINDER HEAD

l.lnstall newvalv€

stem seals.

a. Oi inner surface and

lip ofvi ve stem seal.

b.

Pressrealonto intake

va

lve

guide

bushing unlll

tbottoms

(Figure

513)

5. Compress

valve

sprlng

and instal keepeB

(Flgure

5 15).

Figurc 5-1 5. Conptess

valve spring and insta keeperc

6. Repeat

procedure

for oiher valves.

5-4

Figure 5-13, lnstall

valve Sten Seals

SECTION 5: CYLINOER

HEAD AND VALVES

7. Set

guide plate

in

place

and loosely install rocker arm

assembliet

(ballstud,

rocler

arm and

Jam

nu0.

8. Repeat Step 7 for

other head.

INSTAI.L

CYIINDER HEAD

1- Installcylinder

head with newgasket-

2.

Torque head bolts in sequence shown

to

29.9

Nm

(22

ft.

lbs.)

(Figure

5-16).

3. In5ert

push

rods

into recess in tappets.

Fbute &16.

ADJUST VATVE

CI.EARANCE

1.Set No. 1 cylinder atTDC,

comprcssion stroke.

a.

Adjust rocker

arms and check clearance

(Figure

5-17).

Valve

Cleaance

(cold)

lN and EX 0.0762 mm

(.003').

b.Torquejam nut and

ballstud to 19 Nm

(14ft.

lbs.).

2. Repeatfor No.2

cylinder.

3.Inslallvalve covers with new

gaskets,

Figure 5-18.

a. Torque nuts to 6.8 Nm

(5

ft. lbs.).

REASSEMBIE

1. lnstall cylinderwtappers.
a. Toque M5

scre! 6 to 2.8 Nm

(25

in. lbs).

b.Torque M6 screws to 4.5 Nal(40 in.

lbs).

2. Install spark

plugs.

a.

Torque

to

2l Nm

(15.5

ft.lbs.).

3.

Install

exhaust manifold.

a. Torque scews

to

32.5 Nm

(24

ft. lbs.).

4. Install

blower housing.

a.Torque screws to 4.5 Nm

(40

in. lbt.

5. Install intake manifold with new

gaskets.

a.Torque screws

ro

9 Nm

(14

ft.

lbs.).

b.Assemble

governor

link to carburetor

Figwe ,l8.lntall Valve

Coverc

@"{

nill

@r<

\

/a

TORQUE SEQUENCE

FOF HEADS:

A.B.C-D-E-F

Figurc 5-17, Adjun Valve Cleannces

5-5

SECTION 5: CYUNDER

HEAO AND

VALVES

STATIC

GOVERNOR ADJUSTMENT

1. with

governor

lever clinching

screw loose,

push

on

gov-

ernor lever until

throttle is wide open, Do not bend

governor

link or distort

governor

lever.

2.

Rotate

governor

arm

clockwise as far it will

go (Figure

s-20).

a.Toque clinching

sc€w to 11.6 Nm

(100

in. lbs)-

3. Checkto make sure

that the throltle travelsfrom "WOT"

to

"IDLE." lf it doesnt, the

governor

will need to be rcset

again.

4. lnstall throttle

and choke control cables and check

for

proper

operation.

6. lnstallrotatingscrcen.
a. Torque screws to

1.9 Nm

(17

in. Tbs).

7. Install

finger

guard-

a. lf engine

is

equipped

with socket head screws,

torque

screws to

4.5 Nm

(40

in. lbs).

b.lf engine is equipped

with finger screws, tighten screvls

by hand to approximately 1.3

Nm

(12

in. lbs.).

8. Assemble

aircleanet

WARNINGT Before starting or

running engine, static

adjustment o{ the

governor

must be completedl

Failure

to

mak€ th€ static adjustments

first could

nesult in engine oversp€eding

whi6 may result in

engine damage,

property

danage or

personal

injury

Figwe

5'20. Static Govetnot Adjustment

Figve ,19. Genenl

attenbly

5.6

SECIION 6:

ELECTRIC STARTER

SEcrION CONTENTS

PAGE

GENERA1tNFORMAT|ON.....................................-....--....6'1

TROUBLESHOOTTNG...........--.......................-.................6'1

TEST EQU1PMENT

..................--....-.................................

6-2

TEST STARTER

MOTOR .....-............................................

6'2

Tening Starter So|enoid..............................................

6-2

BATTERY 1NFORMAT|ON ........

........................''............. 6-2

lnnallarion .............................................................-..6-3

CheckingBattery......................................................6'3

Tesri-q8amery.....................

............6-a

Battery Recommendations ...--.......................-........

6_4

Battery Cable Recommendalions................................

6-4

GENER,AL INFORMATION

The starter motor uses

a

geartype

engagement

method, em-

ilarto

an automobile starter When the starter

motor is adLvated,

the

pinlon gear

engages

a ring

gear

attached to

the engtne

fly\,vheeland cranks

the engine.

ENG

NE CRANKS SLOWLY

a. AdditonaLload affecting

pedormance

(see

note above).

b. Discharged

battery

c. Faulty electrical

connecrion

(battery

circuit)

d. Discharged battery

(see

alternators).

e.

Didy or worn starter motor commutator,

bearing, weak

ma9ners, erc.

f. Worn brushes orweak brush

sping.

g.Wrong

oil

viscosity for temperature expeded.

h. Battery leads too

long orWre too small.

i. Batterytoo small.

ENG NEWILL

NOI

CRANK:

a. Fau

iy

sdfety

lnte.locks.

b. Discharged or defedive

battery

c.

Faulty electical connections.

d.

Faulty

narter

motor switch

(open

cltcuit)

e. Open clrcuit

in

stader

motor.

f. Brushes sticking, etc.

g.

Faulty solenoid.

STARTER

N4OTOR SPINS 8UT DOES NOICRANK

ENGINE:

a. Sticking

pinion gear

due io di.t.

b.Damaged

pinion

or

ing

gear

c. Battery

fau

ry

or damaged.

d.Incorrect

rotation

due to

reveBed motor

polariv-a

lmolors

rotate countercockwlse

viewed {rom

pinion gear

e.

Damaged solenoid

sTARTER IVIOTOR SPINS BUTWLL

NOT STOP:

a. Defective starter switch.
b.

solenoid stuck engaged.

TEST

EQUIPMENT

The folowing

is a list of equipment

recommended to ten and

repa r starter

motors.

DIG

IAt [.,1ULTMETER:

A digital multimeter

(VOM)

may be used to readvolts, ohms,

amperes

and test diodes

(rectifiels),

Frgure 6 2.

NOTE: The Digital

MultineEr is equipped with two

fuses

to

prcvent

damage to

the

'',et€r

in the event that the

input

fimits arc exceeded.

ll the mett.r displays a rcading

of 0.00

when testing

DC output check tuses in meter Refer

to

voM opefttoB

manual for

prccedurc

for .he.king

fuses.

6-1

figute

6-1. Stader Motor

TROUBTESHOOTING

NOTE:

lf a stading

problem

it encountercd,

the engine

itseff should

be thoroughly checked to

eliminate it as the

cause of starting

difficulty, It is a

good practice

to check

the

engine for fteedom

of rctation by rehoving the

tpa*

plugs

and tuning the

qankshaft

over slowly by

hand,

to be surc it rctabs freely.

WARNING: DO NOT ROTATE ENGINE

wlTH ELECIRIC

STARTERWITH

SPARK PTUGS REMOVED.ARCING

AT

THE SPARK

PLUG ENDS MAY IGNITE THE GASOLINE

VAPOR EXITING THE SPARK

PLUG HO[E.

SECTION

6: ELECTRIC STARTER

Figurc 6-2. Digital Multimeter

TEST STARTER MOTOR

TESTING STARTER

SOLENOID:

The

solenoid

is a nomallyopen, electrically activated switch.

With the

keyswitch in the "START"

position,

the switch closes,

allowing battery current to

flow

to the stader

motor and crank

the engine.

1

. The solenoid may be lested while mounted on the engine.

2. Ajumper

test lead is required forthistest.

3. Remove

positive

batlery cable

from battery. Then remove

battery cable from stud terminalon solenoid.
Disconnect

yellow

wire from tab terminalon solenoid,

Keyswitch

must

be in "OFF"

pos;tion.

Insert red test lead into vn+

receptacle in meter

Insert black ten lead into

@E

receptacle

in metet

Rotate meter

selectorto

++

'

l

position.

Attach one meter

test

lead

to each

stud termlnal on the

solenoid

(Figure

6-3).

10. Attach one end ofjumper lead to

positive

terminalon

bat

tery

11.

Touch

jumper

wire

to tab terminalon

solenoid.

a. An audibTe "Cllck" should be heard as thesolenoid

switch

"closes."

b.

Metershould make

a continuoustone

(continuity).

Figurc 6-3. Testing Solenoid

BATTERY

INFORMATION

A 12 volt battery is used to

operate

5tader

rnoto6 on Gen-

erac

OHVL v-twin engines. For best starter life and

pedormance,

the battery should

have a rating of at least 525 cold cranking

amps at ooF,

WARNING: Wear eye

protedion

when servi<ing the

battery Avoid

skin contacL lf contact does occur.

Ilush with cold

water and consulta

physician.

CAUTION: Be{ore servicing battery dis<onnect neg­ative

G)

battery

(able

and then disconnect the

positive

(+)

battery cable.

WARNINGT Battedes

produce

hydrogen, an

explosive

gas.

Do not store or charge a battery near an open

flame or devices which utilize a

pilot

light or can

create a 'Dark.

4.

5.

7.

8.

9.

6-2

SECTION 6: ELECTRIC STARTER

Figurc 6-4 Typical BatEry

C

NECK NG BATTERY:

1. Physicalcheck

-clean

if necessary.

a.

Cofiosion
b. Din
c.

Te minalard

(lamp1(\p.urc

-

good

(orditior'

2.

gring

battery to full charge.

WARNING:

DO NOT exce€d rharge rate

of 1/10
ampere {or every ampere ot batt€ry .ating. Consult
battery

manu{acturer for maximum

charqe

recom-

INSTALL"ATON:
l.

Before installing battery connect all equipment to be
operated.

2.

Place battery in holderwith flat base. Tighten ho der down
evenly

untilsnug. DO NOT overughten.

3. Connect

posiUve

ierminalto

politive post

FlRSTto

prevent

sparks caused by accd€nta

gfounding.

Tlghten conne.-

tors securely.

4.

Connect

negative termlnal to negative battery teminal.

Tighten connectors 5ecurcly.

a. Use a taper

charge

(automatically

reduces charge rate).

b. Fillnon-sealed batterycelk

with

distilled watefafter charg-

ing

(for

batteries that have been in seNice).

Note: ll battery

get5

"Hot" to

the

touch or is spifting acid

(gassing)

ex.essively, unplug charyer

peiodi.ally.

3. With batieryfullycharged,

check specific

gravity

rcadings

of each

cell with a Battery Hydrometer and record read-

ings

(Figure

6-6).

All

rcadings should be above ] 250

(compensating

for temperature). lf specfic

aravity

read­inqs varied 0.50 or if allcells read less than 1.225, replace
battery

OPTIONAL CNAFG]NG

SYSTEM

Figurc 6-5. rypical 12 Volt Wiring

Diagran

63

SECTION 5: ELECIRIC STARTER

USE ATEMPERATURE

COIVIPENSATED

HYDROMETER

CHECK

EACH

CELL

AFTER CHAFGING

Figute 5-6. Che.king 12 Volt Batbry Ce s

CAUTION: Do not crank start€r motor tor mor€ than

'15

s€conds without allowing start€r motor to.ool

at least 2 minutes,

TESTING EATTERt

set a digibl rnultimeter to read Dc Volts.

Attach RED meter

test

lead

to

positive(+)

battery terminal.

Attach BLACK meter test lead to negative

C)

batteryterminal.

With ignition switch "OFF,"

press

staner button. lf ignition

switch and starter switch are the

same switch, disconned

wires fro.n spafk

plugs

and

ground

ign tion usingtwo lgnition
Testers. Turn switch to "START." Meter should display 9 volts
or morewhile cranking engine- lf lessthan 9 volts k measured,
replace battery.

EATTERY RECOMT!4ENDATIONS:

The battery size rccommended is

525

CCA@o.

EATTERY CAELE RECOMMENDAT]ONS:

These cablesizesare based on totallength of cable from bat

tery

positive post

to starteL

plus ground

return to battery

negative

post.

#4 AWG - 1.2 m

(6

ft.)or less

t2 AWG - 2.4 m

(12

ft.)or less

6-4

SECTION 7: ALTERNATORS

SECTION CONTENTS

PAGE

20 ANlP REGULATED

ALTERNATOR ....._......................... 7-1

Alternator OutpUt Ten .-............................................ 7-1

Testing DC Output Charging W]re.............................. 7l

Testing Regulator-Reclifier....-----...........-.--...-...... 7-2

20 AMP REGULATED ALTERNATOR

The 20 amp regulated alternatorsystem

provideg

aC

current

through two

output leads to the regulator-rectlfier The regu-

latorrectifier

converts the AC currentto DC, and regu lates the

currenttothe bauery.

The

charg

ng rate willvarywith

engine

RPM and terirperature.

The stator, regulator-rectifier and flylvheel are NOT inteF

changeable

with any other alternator system.

WHEN CHECKING THE ALTERNATOR COMPONENTS,

MAKE THE IESTS IN THE FOLLOWNG SEQUENCE:
ALTERNATOR

OUTPUT TEST:

Temporarily, disconnect stator wire harness {rom regulator-

rectif er.

1. Insen RED test

lead into

vQ+l-

receptacle in meter.

2. lnserl ELACK test

lead into

EEU

receptacle in meter.

3.

Rotite selector to

v-

(AC

volts)

pos

tlon.

4. Attach

RED

and ELACKtest lead

probes

to AC outputter-

minals

(white

wiret, as shown in Figure. 7-1.

(Meter

test

cllp eads

may

be attached to either AC outputteminal.)

5. With the engine

running

at 3600 RPM output should be

no Less man:

26 Volts

-

20 Amp System

6.

lf no

o'low

oJtpJr r,

fould. (hec(

ror

bare

wi'e5

o'a.]y

other obvlous defects.

lf

'shoded'

leads afe not visible,

replace

the stator

TESTING DC OUTPUT CHARGING

WIREI

Asimple test

may

be

performed

to

testthe

DC

outputcharg-

ing wire circuit.

lf a

p.oblem

exists in the wi.ing il

can be

corrected before testing

regulatoFrcctifier

Leave stator

wirc hamess disconnected from regulatoFrec-

tifier

Equipnrent keyswitch must be

in

OFF

position.

I Insert RED test lead into vot1- receptacle in meter

2. Insert BLACK test lead into

@

receptacle ln meter.

3. Rotate selector to

V

(Dc

volts)

posiuon.

4. Attach RED test

lead

probe

to

DC

output wire terminal,

Figure 7-2.

5.

Attach SLACKtest lead

probeto

negatlve battery terminal.

6. Turn equipment

keyswitch to ON

position.

Meter

should

d splay battery

voltage.

7. lf meter does not dlsplay battery

voltage,

check for blown

fuse or broken or shorted

wires,

CAUTION: ATTACH

METER TEST LEADS TO aC

OUTPUTTERMINALS

(WHITE

WIRES) BEFORE

START.

ING ENGINE.IF STATOR IS GROUNDED

(DEFECNVE),

AND METER

TEST LEADS CONTACT CENTER DC

OUTPUT

PIN, ARCIN6 MAY OCCUR WHICH MAY

DAMAGE WIRING.

Figure 7-2,Iesting DC Out4ut Whe

Figurc 7-1. Teting AC

Output

7-1

SECTION

7: ALTERNATORS

TESTING REGULATOR-RECTIFIER:

1.

Using

a digitalmultimeter,

test

the battery

voltage while

the

engine is NOT

running.

2. With

the charging

ststem

prope

y

connected,

staft the

engine.

3. Erlng

the engine

up to normal

operating

speed and

test

the battery

voltage

again.

4. lf

the battery

voltage while

the engine

is runnjng

is

greater

than when

the engine

is stopped,

the

charging system

is

Note:

With

the engine

running,

the battery

vottage

should

be 13 Volts,

BAITERIES

Note: See

Section 6

for baftery

size and

cabte setection

7-2

SECflON

8i

LUBRICATION

SYSTEM

SECTION

CONTENTS

PAGE

DESCRtPI|ON

...._..............................

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

......... 8_.1

PROTECT

ON 5Y5TEM5

Low

O

I

PressL.e

5w t(h

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

........

S t

Inilial

Startup .........................................._.................

8-l

High

Temperature

Sw tch ..........................................

8-l

Sensinq Low Presrure

...................,..,.........................

8-l

Restarting

rhe Engine

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

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

8 1

cHECKtNG

THE ENGTNE

OtL LEVEL ...............................

8_l

cHANGTNGTHEENGTNEOTLANO

FTLTER

...................8,2

Recommended

Oil Iype......................................._......

a-2

otL cooLER ..... ......._........

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

. ......... 8-3

DESCRIPIION

The

Generac

GTV 990t60

OHV|Vtwins

use a ful

pressure

lubrlcation

system with

an orlfilter The

qerotorrype

oitpump

draws

oilfrom a

screened oil

pickup

in the sump

and

pumps

the

oilth.ough the

oilfilter

The

filtered

oilfows through

an oi

gattey

in

the sump

and

is d stributed

to the maln

bearings, connecting

rod

bearings

and camshaft

bearings

Engine oil

pressure

wilt vary

with oi

vrscosity,

ambient

air temperature

diff erences,

operatlng tem-

peratures

and

engine load. Followthe

oil recorlr

me' rodron

on

paqe

8 2 of this

secton.

Oil Pressure-@70.F(21

"C):

15 - 50

psi

{1.0

-

3.5 Bar)

A

pressure

reliefvalve

limitsthe

maximum oilpressure

inthe

system.

PROT€crION

SYSTEMs

LOW PRESSURE

SW]ICH:

The

engine

is equipped wrth a low

oil

pressure

sensor that

closesthe

circuit between

the termina ls when

the oi

pressure

drops

below 8

psi.

lf

one term nalisconnecled

tothe

igniton

kill wire

and the

other termina is

conneced to

ground,

the

engine

willshLtdown

on low

oilpressure.ll the

engineshuts

down by itself

and the fLrel

tank has

enough

gasoline,

check

the engine oil

level.

A

delay

bLrlr inro

tl_e

\l-Jroowr

syste- o.

so-e engile

applications

allows oilprcssureto

buid duing

stading. The

delay

allows lhe

engire lo J,lro.aboLl

I0

econds befo.e

sensr

g

oil

pressure.

f thesystem

senses owoil

pressure

du.ing oper-

aton,

the engine

rhutsdown. The

eng newil

not continueto

run

unti 8

psi

of oil

pressure

s reached.

lf

you

try to renart

the engine within

(five)

5 s€conds

after iishub

down,

lhe engin€

may NOTstart.

The

system n€eds 10

seconds

to reser.

NOIE: lf

you

reshft

engine after

a thutdown

and

have

not

coteded the low

oil

prcssurc,

the

enghte

may .un

for about

10 seconds

as described

above,

and

then it

wil!

H GH TEI,4PERATURE

SWITCH

(OPTONAL):

This

switchS

(not

shown)contacls

close

if the

temperature

shoud exceed

approximately

1400

C

(2840

F),

initating

an

engrne

shutdown. n

cedain applications,

the equlpment

will

automatcally

restaft

and the LED

will

rcset once

the temper

ature

has rcturned

to a safe

operating level.

Figurc

8-1. Engine Protedive

Devices

CHECKING

THE

ENGINE

OIL LEVEL

Th€ o lcapacityofthe

GTV-990,60

OHVtengine

ts

approx_

rmatey

2

quads.

To

check the

engine oit

levet,

proceed

as

I

Remove

the dipstlck

and wipe

it

dry with

a

clean

cloth.

2. Inndllth€

dipstck

comptetety;

then remove

it

again

The

oillevelshould

beatth€ dtpstick,'Fult,

ma*.

tf necessary

add oil

untlthe "Full" mark

is reach€d

DO NOT

F|LL

ABOVE

THE "FULL" MARK

Never operatethe

enginewith

th€ oit tev€l

betow

the

"Add" mark on

the dipstirk. Doingthh

coutd

damage

the €ngine.

8l

I

I

SECTION 8: LUERICATION

SYSTEI,

Any attempt to crank

or start

the engine before

it has

been

properly

serviced with

the re(omnended

oilmay

result

in an engine failure.

O t

C!A\GI

DqOCFDJRt

Your engine

s equipped with

an oil flker

Ch.nge the oil

and

filter after

the flrn eight

(8)

hour5

of

operation. Change

the

oiland oilfilterevery I00

hou6 thereaiier

tf

you

are usrng thG

engine under

dirty or dusty

conditions,

or

in

extremely hot

weather,

change the oil more

often.

Use the following instructions

io

change the

oil

whie

the

englne is nil walml

l. Clean the

area around theoildrain plug,

remove the

plug

and d.ain the oi completely

into

a suitable

container

(Figure

8-3).

2 . When the

oil

is

drained, innall

and tighi€n

the o dra n

plug.

Figurc 8-2.

Lo.ation of oil Filucheck

CHANGING

THE ENGINE

OIL AND FILTER

RECOMMENDED

OIL TYPE:

Using the

proper

Vpe

and weight

of oil rn the

crankcase is

extremely rmponant.

Check

the oilbeforc each

use and

change

the oil regularly.

Failure ro

usethe corrcct

oil, or using dirty

oil,

can cause

premature

engine wear

and

fa luae.

Ure only high

q

ua

lity

detergent

oil rated with Ap

setuice rtae

sficatjon Sl SG

or SH. The recommended

oilweights

inctude

the following:

.

During

summer months:

SAE

30.

An

acceptabte

subnitute

is

SAE 1 0W'30.

After firn oil

change, synthetic

oit is accept-

.

Durlng winter

months:

SAE 5W30,

Synthetic 5W20or

5W

30. DO NOT

USE SAE lOW-40.

F

-20

0

20 40

60 30 1oo

c ao

-io

-10

Io

io

to

Tempgralurc Ranqe

o, E/p6crad Llse

The crankcase

oil capacily is

about 2030 ml

(2.1

qt.)

with the

oilfiller. Wilhout

the lilter,

the oii capacity is

1750 mt

(1.8 qt.).

Use no special

additives. l\4ake

sure lhat the lnil

is level

when lllling with

oil. D0 NOT

OVERFILL.

Figwe

8-3. Oil Dnin

Loation

Figurc 8-4. Renoval

of

Oil Filtel

8-2

SECIION

8: LUBRICATION

SYSTEM

5.

3.

Whenchangingtheoilfiter,usethefollowinginstruction5:
A) Locate

oil fiiler

(Fig

ure

8-4).

B)

Placea suitablecontain-"r

beneath the oilfilterand

turn

the fiher

counterclockwise 1o rcmove

the filter

C) Coat

the

gasket

of a new filter

with engine

oil.

Turn

the new

filter clockwise

until the

gasket

contacts

the

filter adapter,

then tighten an additional3/4

turn.

Remove the

oil fill cap and insert

a clean funnel Inro

rne

oilfill

opening. Flllthe

crankcase with the recommended

oil

until the oii level is

at the

full

point

on

the dipstick.

approximately

2030 ml

(2.I

qt.)are

requ redwhenchang,

ing the oiland

oilfilter POUR SLOWLY

When thecrankcase

G filied

tothe

prope.level,

installthe

oil fill

cap. Start engine

to

{ili

oil filter, rechecucorrecr

orl

ott cootER:

some engines areequippedwth

an oilcoolerTheo

lcooter

is

mounted on the blower housing.

Forced

airfrom the fLylvheel

fanflowsthroughtheoilcoolerfinsdissipating

heatfromthe

engine oil.

The

oil cooler fins should

be cleaned every

100 hou6

and

checked

periodicallyfor

debris

and cleaned

with compressed

air or a soft brBtle

brush.

rigure

8-5. Oil Cooler

8-3

SECT:ON

9: ENGINE DISASSEMBLY

8,4

SECTION 9: ENGINE DISASSEMBLY

SECTION CONTENTS

PAGE

ENGINE

DTSASSEMBLY ..................................................

9-1

ENGINE

DISASSEMBLY

Drdrn oil, re'nove oil

'ilte'

and

rerove engine f'om equ'p-

ment.

Remove spark

plugs.

Remove flywheel, disconnect

stop

switch

wires at armatures and remove armatures

(see

Section

2). Remove cylinder

heads

(see

Seclion 5).

1. Remove the following

parts

(Figure

9'1):

a.

Brcather Assembly b. Alternator

c, Backplate

d. Starter Motor

2. Remove ctankcase cover
a. Discard

gasket

and O-ring.

3. Rotate c€nkshaft

and

camshaft

untilliming marks allgn

and remove camshaft

(Figure

9-2).

Note: lf

necessary,

place

the engine

flWheel side down

to

pfevent

tappets ffom catching on

the camshaft

a.

Remove tappets.

Figwe 9'1

. Remove Alternatot

Backplate, S|d,raer Motor

..1:

,'

@ob

Figwe 9-2.

9-1

SECTION 9:

ENGINE DISASSEMBLY

Note: Remove

any carbon or idge at the top of the .ylin-

der

bores

to

prevent

breaking ings when rcnoving

piston

and aonneding rod assemblies.

4- Remove No. 2

connecting rod c:p and

push

conn€cting

rod

and

piston

assembly out of cylinder

(Figure

9-4).

a

Reasse-ble

cao ro

rod

lo

prevenl

'nrercharg:n9

5. Repeat{or renraining

cyllnder.

6. Remove

crankshafl

(Figure

9-5).

ligwe

9-5. Renove Oankshalt

7. Remove

oil

pump

frcm crankcase

cover

Note: clean

all suiaces of

gasket

mateial.

Remove

oil

seals and

thotoughly dean components in

solvent. Orga-

nize components,

keeping

pat's

which

are assemblies

together

Figute

9-3, Renove cj,l]shalt

Fiqurc

9-4. Renove Pinons and

Connecring Rods

Figure 9-5. Renove Oil Pump

92

SECTION

l0: CYUNDER

& CRANKCASE

COVER

SECTION CONTENTS

......................................PAGE

cRANKCASE..........................................._.__..._.............

t0-1

Check Crankcase ............--......................................

1 0-1

Resizing

..................................................................10-1

Cy|inderFinish........................................................1G2

Cleaninq,,,..-.---...................,,.,,,,,,,,,,,.,.,..,................

10-2

BEAR1NGs..............._.._.......................

. .........1G2

Check Mag Bearing -..-.................--..---....................

1o-2

Remove Mag

Bearing .-.--.....-..---...---........................

10-3

Innall Mag Bea ng

......... __.............__....____._..............

I0-3

Check PTO 8eadn9s

.............................-.-..-.............

104

Remove/lnstall

PTO 8eaf in9.........................__...........

t0-4

Instali PTo

oil Seal ..................................................

10-4

Check Camshaft 8earin9s...........................-............

104

Oil Seals ..................................................................

10-4

CHECK

CRANKCASE

Check crankcase

for cracks, stripped threads

or broken fins.

Check cylinder bores

fof dar.age orscoring.

l.Check

cylinder head mounting

surfacefor distortion with

a

straight edge, Figu€

10-1.

lf mounting surfaces

are distorted more

than.004'

(0.1

mm),

the crankcase mun be rcplaced.

NOTE: ff

qlinder

borcs arc within

srycification

and show

no

signs

of

scoaing ot other damage.

new

piston

ings

may be installed

Wviding

the

.ylinder bores

arc rc<on-

ditioned using a igid hone

with tinishing

stones,

to

rcstote the

prcpet

(oss

hakh

angle in the

.ylinder botet

The

proper

cylinder cross hakh

ensurcs

Noper

lubicatjon

ahd

piston

nng

hrcak in.

Refer to

'Cylinder

Finish

(C

ross Hatch)"

below for

correct

pro-

cedure for

installing cross hatch.

TOP

BOTTOIV

Figurc 10-3. Measute

at Six PoinB

RESZING:
Note: Ovefsize kits

are NOT available.

DO NOT borc

.ylinden
CYLINDER FIN SH

(CROSS

HAICH):

Finishing nones

are used when reconditioning

a cylinder

bore. Thefinishing

stones will

produce

the

correct cross hatch

necessaryfor

proper

lubrication.

The cor€ct

cross hatch

angle

is approximately 45

degrees, Figure 10-4.

Figute 10-1.

Che*ing Cylindet Head Mounting Surtace

2.Check cylinder bores

for wear using telescoping

9au9e

and

dialcaliper

Standard Borc Size:

90,00-90,025 nn

(3.:A3-3.51U")

a. Measure cylinder bore in

6

points

at right:ngles

as shown,

Figures I0-2 and 10-3.

b.lf cylinder

bore is worn more than .003'

(0.075

mm) or

more

than .0015'

(0.035

mm)out

of round, ft must

be

reptaceo.

Figurc 10-Z

Che& Cylindet

Boft

101

SECTION

'10:

CYLINDER & CRANKCASE

COVER

It is rccommended that the cylinde.

bores be reconditioned

to restore the cross

hatch when

new

piston

rlngs

are

to be

innalled in a cylinderthat iswithin specification.

Be careful not

to

hone ove6ize or itwillbe necessarv

to

reolace

the crankcase.

Honing

is

donewithava ablespeed L2",

podab

e drilland

a honing fixture. See

Page

l0-5 for dimensions

to make a

honing fixture. Use tlvo crankcase cover mounting

scrcws to

fasten the cr€nkcaseto the honing fixturc, Figure

10-5.

Clarnp honing fixture and crankcase securely

in a

vise

at a

convenient work height.

Plac-" hone in middle of cyllnder bore. Tlghten

adjusting

knob with

finger

untilstones

fit

snugly against

cylinder

wall.

DO NOT

FORCE.

Cut a

wood

block and

place

inside

rylinder

to

prevent

hone f.om exrending further than

3/4" to 1

'

(19

mm

to

25 mm) below cylinder

bore.

Place

hone

dive shaft

in

chuck of

portable

drill and tighten. Be sure that

cylinder and

hone are centered and aligned with the drilspindle.
NOTE:

To

produ.e

the

prcper

(oss

hatch finish use a dd

speed of apyoximately

2OO RPM

and

/P-60

Hatch nrckes

per

minvte.

Lubfi.ate hone

libera y to

prevent

build up

on finishing stones,

NOTE: Automatic transmission fluid is

an accebtable

honing oil. Another ac.eptabte honing oit

can be tnade

by mixing 4

patts

No. 30 weight oil with

I

patt

kercsene.

with hol running wat€r

Repeatwashing

and

rinsing unlilallt€ces

oi hon n9

grh

a€

gone.

Honing

git

is

highly

abGsive and

willcause rapid wearto all

ofthe lnternal components of the engine unless

ii is

completely

Figwe

| 0-4.

Cylinder Crcss

CLEANING:
IT IS MOST IMPORTANT

THAT THE ENTIRE

CYLINDER AND

CRANKCASE

BE THOROUGHLY CLEANED

AFIER HONING.

Finwash thecylinderand crankcasecareiully in

a solventsuch

as

kercsene or commeKlal solvent. Then thorough

ywash

cy

inder

afd

cGnkcase using a stiff brush

with

soap and

hotwater

Rinsethooughy

Figurc, 0- 5. Honing Cylinde6

NofE: when cylinder and .rankcase have been thor­oughly cleaned, use a clean white ag or napkin and
wipe the cylinder borc. ff honing

grit

is

prcsent

it wi

appear as a

gEy

rcsidue on rag. lf any honing

gfit

is evi-

dent re-wash and dnse entirc

qlinder

and

(ankcase

and

.heck again. When therc is no tace of honing

gfit

on hg.

the

qtindet

is

$ope

y

cleaned. Then oil cylindet borc

to

pfevent

fusting,

BEARINGS

CHECK MAG BEAR]NG:

Check

magneto

bearing

for damage. Damaged bearings

must be replaced. Lf not daraaged, check

for wear

using a tele-

scoping

gauge

and calper

(see

Figure 10-6). Measure

atseveral
locations. lf the measured diameter is larger than 38.25 mm
(1.506"),

the bearing must be rcplaced.

The diameter of the crankshift may also make it necessary
to rep acethe bearing.see Secrion 11 forthe cfankshaft mea­SuTement detars.

REMOVE IV1AG BEAR NG:

2.Placecrankcaseflat upon a

pressand

remove bearing

using

a bushlng driver

(Figure

10-7).

raN

,dffiW,r.'\r'4

10-2

SECTION l0: CYLINDER & CRANKCASE

COVER

31,75rnm!O,1mm

[1.25'40.004 ]

CHECK PTO BEARING

The PTO bea

ng must

be

replaced i{ it

is damaged or if it

measures larger than 42.25mm

(1.663")

in diameter

(see

Figure 10"8).

The diameter

ofthe crankshaft may

al5o

make

it necessary

to replace the bea

ng.seeSection ll

forthe crankshaft mea-

surement details,

a4

smmao,1mm

h,752'10.004'l

o37.9mmi0.imm

[41.492'i0.004']

@41.1mmro.1

mm

1O1.618"r0.oo'l'l

Figure 10-7. Mag Bea ng Divel

INSTALL MAG EEAflING:

1. Place crankcase on a

press,

sea sidedown.

a. l\lake sure that the dankcase is supponed by the sea boss.

2.

set the

new

beaing

in

the crankcase

with the notch

up

and the oil

holes

lined up

with

the

passages

in the

crankcase.

3. carcfully

slide the

bushing driver into

the beaing and

press

the bearing in until it is 0.25-1.27mm

(.01-.05')

below the su.face,

4. Remove any material left in the oil

passage.

5. lnstall new

oiLseal

with

sealing

lip facing ln.

a, Press oil seal until flush with crankcase.

@45.1mm$.thm

[O1.2/6'10.004'l

041.9mmr0.1mm

[91.65't0.004']

Figurc t0-9. nO Beaing Divel

REVOVU\STALL

PTO BEAqING

The removaland installation

prccedure

for

the

PTO

bearing
is the same as for the mag bearing. See Figure 10-9 for the
bearing driver used in this

procedure.

!'

Figurc 1?-5. Che.k Mag Beaing

FiguE t0-8. Check PTO Beaing

10-3

SECTION

10: CYLINDER &

CRANKCASE COVER

INSTALL PTO OIL SEAL:

lnstalla new fio oilsealand

press

itin und h is 1.5mm(l/16")

below the mounting surface.
CHECK

CAMSHAFI BEARINGS

lJse

a telescoping

gauge

and caliperto check camshaft beaF

ings. lf

camshaft

bearings are woTn, crankcase or crankcase

cover must be replaced.

(Forveatical

shaft engines, the

gero-

Mag Bearing Reject Dimension:

20-06mm

(.790")

PfO Beafing Rejed Dimension: 18.06mm

(7rr')

O]L SEALS:

Always

installnew oil

seals

whenever

engine

i5 dlsaslembled
for major servicinq or when repai ng bearings, Lub cate 5eal­ing edge of oil seal with clean engine oil before assembly.
Alw;ys use the correct seal

protectorto prevent

damaging oi

seal.

Figurc 10-11. Chec*ing Mag Side Camshaft Beaing

Figurc 10-10. Che&ing PfO Side Canshaft Beaing

I0-4

SECTION 10: CYLINDER & CRANKCASE COVER

16.smm

[0.65']

2'16mm

18.504"1

183.5mm

P.224'l

Ol2mm

1o.473"1lYP

MATEHIAL: WOOD

25.4mm

I1'lx

216mm

[8.5"]

x 254mm

[10.0"]

CLAMP THIS END IN VISE

254mm

[10.0"]

Figurc 10-12. Honing Fixtue

10-5

SECTION 10:

CYLINDER

& CRANKCASE

COVER

10-6

SECTION

11:

CRANKSHAFT

& cAMSHAFI

SEcrION

CONTENTS

CHECKING

CRANKSHAFI...

CHECKING

CAMSHAFT......

.....

CHECK]NG

CRANKSHAFI:

PAGE

I1,1
11-l

CHECKING

CAIISHAFT:

hspect

gear

teeth. lobes

and

journals

for wear

and nicks,

Figure

11-2.

Camshaft

journa

I and

lobe reject

sizes are

shown

below Replace

cam

gear

if not

to specification.

Inspect

crankshaft

threads, key\,vays

and

lming

gear

for

damage

orwear

lf threads, keyways

ortiming

gear

are dam,

aged orworn,

replace

crankshaft. C h€ck

journats

for

scoring.

Ifjournals

are scored,

replace crankshaft.

Check

journa

s

for

wear

see crankshafr

rejedt sizes,

Mag

Intake

!obes

Exhaust

4.745"

o.1a4'

1.221'

1.221.

(17.93

nrm)

(19.93

mm)

(31.02

mm)

(31.02

mm)

ALL

1.648'

'|.534"

I 490'

(a1.8s

mm)

(37.85

mm)

(38.96

mrn)

FLYWHEEL

KEY

PTO

JOUFNAL

TIMING

LOBES

Figwe

11-2.

Che*ing

Canshalt

otL

GALLERY

CFANKPIN

f iqurc

| 1

-1.

Che.k ing

Qankshalt

Camshaft

Reiect

Size

Crankshaft

Reject

Sizes

Crankpln

PTO

Mag.

Joumal

journal

I1-1

SECTION

.I.I:

CRANKSHAFT

& CAMSHAFT

SECTION

12:

PISTON, RINGS

& CONNECTTNG

ROD tNSpECTtON

& ASsEMBLy

SEcTION

CONTENTS

PAGE

GENERAL

TNFORMAT/ON..._..........................................

12_l

DISASsEMBLE

PISTON AND

CONNECTING

ROD

....,.....

12,]

cHECKTNG

ptSTON

AND

R]NGS................................_...

12,1

CHECKING PISTON

PIN AND

CONNECTING

ROD

.... 12

2

ASSEMELE

ptSTON

AND

CONNECTTNG

ROD ................

12

2

AsSEMBLE

PJSTON

RTNGS

TO

ptSTON

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

. 12,3

GENERAT

INFORMATION

It is recommended

that new

piston

rings

be innalted

when-

ever the

engine is disassembled

for

rnajorservicing

or overnaur,

provdr,rg

thar

ryhnde

bo.es

are wtl

ir

sperrfrcation.

Remove

any

carbon or ridge

atthe

top of

the cylinder

bore.

This

will

prevent

breaking

the ringswhen

removingthe piston

and connecting

rod from

the

engine. Remove

the

connedring

rod

cap. Push

the

piston

and

connecting

rod

out through

the

top

of the cylinder

Measure

cylinder bores

before

checking

pistons

and ringr.

see Sedion

10.lf cylinder

bor€s

are outoftolerance,

it willnot

be necessarytoaheck pistonsand

rrngssince

a newcrankcase

and

piston

assemblies

willbe

used.

ll

the cylinder

bore is more

than

.075 mm

{.003,)

oversize,

or .035 mm

(.0015")

out of round,

it must

be replaced.

DISASSEMBLE

PISTON

AND

CONNECTING

ROD

1. Remove

piston

rings

using

ring expander.

a. fhen remove

oil ring.

Figurc

t2-t. Renove

Rjngs

2.

Disassemble

piston

from

connecting

rod,

Figure

t2-2.

a Remove

piston

pin

locks.

b. Piston

pin

is a

slip fit in

prston

and

connecting

rod.

Keep

pGtons

and connecting

rods

together

as an

assembly

Do not mix,

Figurc

12-2,

Remove

pistoD

pin

Lock

CHECKING

PISTON

AND

RINGS

lf

the cylinderis

not

goingto

be replaced

andthe prnon

snows

no signs

of scoring,

the

piston

should

be

checked.

Carefully

remove

ca|bon from

ring

grooves.

1. Checkside

clearance

of ring

grcoves

using new

rjngs, Figure

I

2-3.' a 0.1omm

(

004"\

feeter gduge

fo.

t're ( ompres\ion

ngs

or 0.20mm

(.008")

for

the

ojlring

can be tnseneo,

tne

flng

groove

|5 worn.

The

piston

must be replaced.

Figurc

12-3. Check

Ring

crcoves

2. Check ring

end

gap,

Figure 12-4.

a. Clean

c.|bon from

end of rings

and

insert

approximatety

1

{25

firm)

into

cyllnder

Reiect Dimension (comqession

ngs):.020" (O.S1mm)

Reiect

Dimension

(oil

rings): .045"

(1

.1

Snm)

b.lf

gap

is less

than

rejec

dimension,

remove

some

maer

ial'rom

$F

end o.rne

ingtoachever1emini^Jmgap

3. Check

piston

pln

bore,

Figuret2

5.

a. Reptace if

grearer

than

.7886'

(20.03mm)

or

jf

ir

is .OOO5

,,

(01

mm)

out

of round.

t

SECTION

12: PISTON, RINGS & CONNECTING ROD INSPECTION & ASSEMBLY

Figute l2-4. Che&ing Ring End Gap

Figure 12-6. Check Piston Pin

CONNECTING ROD REJECT SIZE

Crankpin

Bearing Piston Pin Bearing

1.539"

(39.09mm)

.7894'

(20.05mn)

Figute l2-5. Ched< Piston Pin Eote

CHECKING PISTON PIN AND CONNECTING ROD

1-

Check

piston

pin,

Figure 12-6.

a. Replace if less than .7862'

(l9.97mnr)or

if it is .0005'

(.01

mm) out of round.

2. Check connecting

rod

bea ngs.

Note: ll ctankpin bearing is s.orcd or won the.onne.t-

ing rcd must be tepla.ed.

PISTON PIN BEARING

Figure l2-7, Check Rod Beaingt

ASSEMBLE PISTON AND CONNECTING ROD

Lubric:te

parts

with engine oil and assemble *1

piston

and

connecting rod, Figure

12-8.

l.Notch

or casting mark on

piston

must be on flywheeJside.

2-Number " 1 ' on

connecting

rod must face PTO

side

(oppo-

site

notch

or casting mark on

piston).

d l,rstallpinon

pi,r

locG with needle rose

pliers.

Lubricate

parts

with engine oil and assemble #2

piston

and

connecting rod, Figure 12-9.

l.Notch

or casting mark on

piston

must be on fly\,vheelside.

2.Number

'2'

on connecting rod mustface PTO side

(oppo-

site notch or casting mark on

piston).

a.Installpiston

pin

locks with need e nose

piiers.

CRANKPIN

BEAFING

12-2

SECTION 12:

PISTON, RINGS & CONNECTING

ROD INSPECTION & ASSEMBLY

ASSEMBLE PISTON

RINGS TO PISTON

Install

piston

ringsusing ngexpanderwhen installingcenter

and top compression

rings,

1. Installoilringexpander
a. Install lower scraper ring,

a.lnstall upper scraper ring-

2, Install center compression ring

with

chamfer

up.

3. Install top compression rlng-

Note:Top compression ng may be installed with eithet

Fiourc 12-& Assenble *l Rod And Piston

Figurc 12-9. Assenble S2 Rod And Pinon

TOP COMPAESSION R]NG

/CENTEF

COMPF€SSION FING

Figurc t2-10. Piston Ring lnstallatton

12-3

SECTION 12: PISTON, RINGS & CONNECTING ROD INSPECTION & ASSEMBLY

'12-4

SECTION 13: ENGINE

ASSEMBLY

SECTION CONTENTS

lNsTALL CRANKSHAFr ............__........................_.........

13-1

|NSTALL PISTON AND CONNECTTNG

ROD .................... 13-1

tNsTALL CAMSHAFL............_....._...................____.........

t3-2

tNSTALL CRANKCASE COVER .._.......................__..........

13-2

GENERALASSEtV8LY.................__.................................

t3-3

tNsTA11 8REATHER ......................................................

13-3

|N5TALLFL\1|/HEEL.......................

............13-3

ADJUST tGNtTtON COtL AtR GAP..................................

13-4

tNSTALL CYLTNDER HEADS ............................................

13,

ADJU5TVA1VE5............................._..............................

13-

INSTALL CRANKSHAFT

Lubricatemagbearingandlipsof

oilsealwithengineoiland

installcrankshaft.

Figure 13-1.

Insta ing Qankhaft

INsTATL

PISTON AND CONNECrING ROD

Note: lnstall

*t

pinon

and connecting rcd tiEL

1 - Oil

piston

ngs,

piston

skift, and compress rings with Ring

Comprcssor, Figure

l3-2.

a.

Place

piston

and ring compressor upside down

on bench

with

projedions

on comprcssor facing

up.

b.Tlghten ring

compressor evenly until rings are fully

com-

pressed.

c. Then loosen ring compressor very

slightly so th:t com

pressor

can be

rotated

on

piston

skirt while holding

connecting rcd, Figure 13-2.

d, Remove connecting rod cap.

Figure 13-2. Conpresting Rings

2. Lub cate cylinder borcs and crankpin and rotate

crankhaft

until it is at bottom of stroke.

3. Install #l

piston

with notch or

casting mark towards fty-

wheelside, Figurc 13-3.

a.

Push

piston

down

by hand untilconnecting rod

is seated

4. Assemble

connecting rod cap to

rod with

match marks

allgned, Figure 13-4.

a. Torque screws to 24.4 Nm

(18

ft. lbs.).

FIING

COMPFESSOB

Figure 13-3, lnsElling Piston And Conneding Rod

13-1

SECTION 13: ENGINE

ASSEMBLY

Figurc li-5.

tnsta ing

Canshaft

Figurc

t3-4. Toryue Connec.ting

Rods

5. Rotatecrankshafttworevolutionstocheckforbinding.

Rod

should also

be free to movesideways

on crankpin.

Repeat

Steps 1-5 for #2 cylinder.

Note:

The numbef

1 on *t .onnecting rod

and the

number

2 on *2 connecting

rcd must be

facing PTO

side.

lmportant

Failurc to

use a torque wrcnch

.an rcsuh

in

loose

conneding rod

scrcws causing brcakage

ot tight

conneding

fod s.rews

causing saoring,

INSTATT

CAMSHAFT

Lubricate

tappets,

cam shaft

joufnah

and lobes

with

eng ne

o|].

1. Installtappets.

2. Aligntifting

markson

cam shaftand

cfankshaft

gearand

installcam

shaft, Figure 13 5.

3. Atsemble

governor

spool

io

governor

shafi.

a. Make

sure that

spool engages flyweights.

b.Install new

"O'Lring in crankcase.

INSTALL CRANKCASE

COVER

Lubricate PTO

and cam

gear

bearing.

1. Rotate

governor

shaftsothatthe piddle

rests againstthe

cover, Figure

l3-6.

Figute 13-5.

Rotating covehot

Shaft

2. lnstall

crankcase cover

with new

gasket.

Note: fi

the oil

pump

dfive

is not aligned,

the cover

will

not slide

completely on.

Turning the

uankshaft may

align the

oil

pump

drive.

3. Install

governor

suppod bracket.

a. The allen head

crankcase bolt

willneed

to be backed off.

4. Torque

screws in sequenceshownto

47.5 Nm

(35ft.lbs.),

Figure 13 7.

5. Check crankshaft

end

play.

tf

ess than 0.05mm

(.002,,)

there may

be an assembly

probem.

'13-2

SECTION

13:

ENGINE

ASSEMBLy

)

TORQUE

SEQUENCE

FOR

CRANKCASE

COVER

:

1-2-3-4-s-6-7-8-9-10

Figwe 13-7

GENERALASSEMBLY

l.

Install alternator,

Figurc

13-8.

a. Torque

screws to 12.2

Nm

(9

ft. lbs.).

Figurc t3-8,

tnstall Alternatol

2. Innall

back

plate.

a. Torque

screws to l0 Nm

(7.4

ft. lbs.)

3. Install

stader motor.

a.Torque

screws to 24.4

Nm

(18

ft. lbs.).

Impottant: Route

altenator

whes through

rctief in

back

plate.

DO NOT

pinch

whes,

a.

As,Fmble ion

ion co ls ro

engine, Figure.3-i.

a.l\,,lounting

holes in coil

are slotted.

push

coit away from

.

fly!,r'heelas

faras

possible

and

tighten

one screw

to hotd

coilin

place.

5. Repeai for

second coil.

Note:

The side shown

in Figurc

13-9 must

face up

on both

coils ot the engine

will not fundion

Noperly

6. lnsta

I

ground

wire

onto tab terminal

on ignition

coils.

lmportant

: Make surc wircs

arc routed

over

coil mount-

ing

pos6.

INSTAI.t

BREATHER

1. InseJt

breather material.

2. Instal

breather

assembly and

gasket.

3. Torque

boltsro 6.8 Nm

(5

fr. tbs

)

INSTAIL FIYWHEEL

lmportant:

Clean flwheel

and cankshalt

taper

rcmov_

ing alloil,

ditt or

qrcase,

I nsert flywheel

key into

crankshaft.

2. Assemble flylvheel

to crankshaft.

3.

hstal washerand

fly.vvheelnut.

4. Toqueflywhee

nutto 204Nm

(150ft.

bs.),Fgure13_jO.

Figut€ l3-9. lnstall

coils

SECTION

13: ENGINE ASSEMBLY

a. Torque head bolts

in

sequence shown

(Figure

13-12) to

27 Nm

(20

ft. lbs.).

3.lnsen

push

rods into

recess

in tappets.

ADJUST IGNITION COILAIR 6AP

'LRotate

flylvheel until magnet is under coi

laminations.

2.Placethickness9au9e,.008"-.012'

{0.20-.30

mm)

between

magnet and coil laminations, Fig ure l 3- 1

.I

.

TORQUE SEOUENCE FOR HEADS:

A.B,C,D.E.F

Figwe 13'12lnsli Cylinder Head

INSTALL ROCKER ARMS

1. Lu bricate rocker arms and ballstuds with

clean engine oil.

2, Assemble ball studs, rccker arms,

jam

nuts and

guide

plates

to cylinder head,

Figu€ 13-l3.

a.

Make

surc that

the

push

rods are in the

proper

location

on the tappeti and the

rocker

arms.

3. Loosen mounting

screw so

magnet will

pull

coil down against

thickness

gauge.

a. Torque screws to l2-2 Nm

(9

ft. lbs.).

4. Rotate fll1,1/heelto

emove thickness

gauge.

5,Repeat for second coil.

INSTATI. CYLINDER HEADS

1. Installcylinder head with new

gasket,

Figure 13-12.

2.

Lubricate

threads of

head

bolts

with

oil.

FOCKER ARM

Figwe 13-10. Torque Flwheel

Nut

@".fr

nilil

@r,<

\
/B

Figute 13-11. Adjust

Ak Gap

13-4

Figute 13-13.,lnstall Rod<et Ant

SECTION 13:

ENGINE ASSEMBLY

ADJUST VALVE

CLEARANCE

l. Set No.I cylinderatTDC

fiop

Dead Center),

compression

nrcke.

a. Adjust rocker

arms and check

clearance, Figure 1314.

Vatue Clearance

(cold)

lN and EX .003"

(0,075

mn)

b. Torque ball studs and

jam

nuts to 19 Nm

(14

ft.

tbs.).

2. RepeatJor No.

2 cylinder

3. Installvalve cove6 with

new

gaskets,

Figure

t3-15

a.

Torque

bolts to 6.8 Nm

(5

ft. lbs.).

GENERAT ASSEMBLY

1. Install

Cylinder shields

(wrappers).

a. Torque M5 screws to 2.8 Nm

{25

in. lbs.).

b- Torque M6 screws

to

4.5 Nm

(40

in. lbs.).

c. Connect ignition

9rcund

wire to ignition

kilterminal in

backing

plate.

Figurc 13'15..lnttall

Valve Cove|s

Figurc 13-t 4..

Adjust Valve Cleannce

@

rrncen

cueno

@

norelruo

scneen

INTAKE

MANIFOLD

ASSEMBLY

@

orr cooren

@

erowen rousno

@

ueeen wnaeeen

@

rowen wnreeen

@

vtve

coven

Figute 13-16.. IDS.'aII

Blowet Housing

SECTION l3: ENGINE

ASSEMBLY

2. Assemble

governor

leverto

governor

arm. DO NOTtighten

at this time.

3. lnnall

speed adjust assembly_

a. Torque

screws to 6.0

Nm

(53

in. lbs.).

4.

lnstallexhaust.

a.Torque screws

to 27.0 Nm

(20ft.

lbs.).

5. Installfan

and retaining

ring.

a. Torque screws

to 21.7 Nm

(16

ft. lbs.).

6. lnstall

blower housing.

a.Torque

screws to 7.0

Nm

(65

in. lbs.).

7. Install

rotating

Screen.

8. Install intake

manifold assembly.

a- Toque

bolts to 19

Nr.

(14

ft. lbs.)

9. Installfinger

guard.

a. lf engine is

equipped with

socket head

scrcws, torque

screws to 4.5

Nm

(40

in. lbs).

10. Connect

governor

llnkage

and

speed contrcl tinkage.

I1.

Install spark

plugs_

a.Torque spark

plugsto

19

Nm

(14

ft. tbs.).

ADJUST

6OVERNOR

Note: Refer

to Sedion

4, Page

4-2 fot Stati.

covehor

Adjustment

WARNING: BETORE

STARTING

OR RUNNING

ENGtNE,

static adjustment

of the

governor

must be com-

pletedl

Failure

to make

the natic

adjunments first

could

result in engine

overspeeding

whid may

reruh

in engine damage, property

damage

or

personal

injury

SECTION