Onan BGM, NHM, 7NHM-FA/26105F Service Manual

f •

~'

-

r:·"A.·.:._,

..,.-,·

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' e

Service Manual

BGM, NHM

Printed in U.S.A.

0

965-0531

2-96

Safety Precautions

Thoroughly read the OPERATOR'S MANUAL before operating the genset. Safe operation and top performance can be obtained only with proper operation and maintenance.

The following symbols tial hazards to the operator, service person and equipment.

M•M~®#!;I

Alerts you to an immediate hazard

which will result in severe personal injury

IAWARNINGI Alerts you to a hazard

practice which can result in severe personal injury

in

this Manual alert you to poten-

or

death.

or

unsafe

or

death.

lA

CAUTION I Alerts you

practice which can result in personal injury

to

a hazard

or

unsafe

equip-

ment damage.

Electricity, fuel, exhaust, moving parts and batteries

in

present hazards which can result ry

or death.

GENERAL PRECAUTIONS

• Keep ABC fire extinguishers handy.

• Make sure all fasteners are secure and torqued properly.

• Keep the genset and its compartment clean. Excess oil and oily rags can catch fire. Dirt and gear stowed in

the compartment can restrict cooling

• Before working on the genset, disconnect the nega-

(-)

tive ing.

• Use caution when making adjustments while the genset parts can cause severe personal injury or death.

• Used engine oil has been identified by some state and federal agencies as causing cancer or

reproductive toxicity. Do not ingest, inhale, or

contact used oil or its vapors.

• Benzene and lead identified by some state and federal agencies as

causing cancer or reproductive toxicity.

ingest, inhale or contact gasoline or its vapors.

• Do not work cally fatigued or after consuming alcohol or drugs.

• Carefully follow all applicable local, state and federal codes.

• Generator output connections must qualified electrician

codes.

battery cable at the battery to prevent start-

is

running-hot,

in

some gasolines have been

on

the genset when mentally or physi-

GENERATOR VOLTAGE IS DEADLY!

in

severe personal inju-

air.

moving or electrically live

Do

not to

be

made by a

accordance with applicable

• The genset must not be connected to the public utility or any other source of electrical power. Connection could lead to electrocution of utility workers,

An

damage to equipment and fire.

be

ing device must tions.

• Use caution when working ment. Remove jewelry, make sure clothing and shoes are dry and stand on

the ground or floor.

FUEL IS FLAMMABLE AND EXPLOSIVE

• Keep flames, cigarettes, sparks, pilot lights, electrical arc-producing equipment and switches and all other sources of ignition well away from areas where fuel fumes are present and areas sharing ventilation.

• Fuel lines must rated or shielded from electrical wiring.

• Use approved non-conductive flexible fuel hose for fuel connections at the genset.

ENGINE EXHAUST IS DEADLY!

• Learn the symptoms of carbon monoxide poisoning in

this Manual.

• Never sleep ning unless the vehicle has a working carbon monoxide detector.

• The exhaust system must dance with the genset Installation Manual.

Do

not use engine cooling air to heat the vehicle in-

• terior.

• Make sure there the genset

MOVING PARTS CAN CAUSE SEVERE PERSONAL

•

Do

not wear loose clothing or jewelry near moving

parts such as PTO shafts, fans, belts and pulleys.

• Keep hands away from moving parts.

• Keep guards

• WEAR SAFETY GLASSES and while servicing batteries.

• When disconnecting or reconnecting battery cables, always disconnect the negative cable first and reconnect it last to reduce arcing.

in

a confined area.

INJURY OR DEATH

in

BATTERY GAS IS EXPLOSIVE

used to prevent interconnec-

on

be

secured, free of leaks and sepa-

the vehicle while the genset

is

ample fresh air when operating

place over fans, belts, pulleys, etc.

approved switch-

on

live electrical equip-

a dry wooden platform

is

run-

be

installed

DO

in

accor-

NOT SMOKE

(-)

battery

·~

MBL-1

Table of Contents

SECTION TITLE

SAFETY PRECAUTIONS 1 INTRODUCTION 2 GENERAL SPECIFICATIONS 3 DIMENSIONS AND CLEARANCES

4 TORQUE SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 PREPARING FOR SERVICE

Troubleshooting

Safety Special Tools Removing the Genset

6 ENGINE - PRIMARY SYSTEMS

Troubleshooting Engine Primary Systems

Exhaust System Cooling System Ignition System Cylinder Compression Test Crankcase Breather Assembly Governor and Carburetor Adjustments Fuel System

Electric Starter

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

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

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

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

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

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

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

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

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

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

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

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

Inside Front Cover

PAGE

1-1

2-1

3-1 4-1 5-1

5-1 5-1 5-2 5-2

6-1 6-2

6-6

6-7 6-1 6-13 6-13 6-14 6-19 6-35

0

7. CONTROL

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control Description {Mechanical-governor generator sets) Control Operation

Control Description {Electronic-governor generator sets)

Control Operation

Control Troubleshooting

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

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

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

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

A.

WARNING:

A.

The engine exhaust from this product

contains chemicals known to the State

of California to cause cancer, birth

defects or other reproductive harm.

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

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

7-1 7-1

7-2 7-3 7-8

7-1

0

7-15

SECTION TITLE

PAGE

8. GENERATOR Generator/Control Component Descriptions

Generator Operation Generator Troubleshooting Generator/Ignition Component Service Brushes and Slip Rings Generator Testing

9 ENGINE BLOCK ASSEMBLY

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Oil Filter and Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cylinder Heads Valve System Gear Cover Governor Cup (Mechanical} Timing Gears and Camshaft

Lubrication System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Piston Assembly Crankshaft Cylinder Block

Bearings

Oil Seals

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

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

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

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

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

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

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

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

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

....... · ...........................................

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

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

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

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

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

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

8-1 8-1

8-2 8-5

8-8 8-13 8-15

9-1

9-1 9-1

9-1

9-4

9-9

9-1

0

9-1

0

9-11

9-13

9-1

7 9-18 9-21

9-22

1 0 SERVICE CHECKLIST

11

Appendix

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

Mounting

Lubrication

Wiring

Initial Start and Adjustments

Output Check

Exhaust System Fuel System Control Mechanical

WIRING DIAGRAMS

A TROUBLESHOOTING CHARTS . . . . . .

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

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

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

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

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

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

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

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

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

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

..

. . . .

..

. . . .

.. . ..

. . . . . . . . .

1

0-1

1

0-1

1

0-1

1

0-1

1

0-1

1

0-1

1

0-1

1

0-1 1 0-2 1 0-2

11-1

.. . A-1

ii

Section

1.

Introduction

This is the service manual for

the

Series

BGM

and

NHM generator sets (gensets). Read and carefully

of

the

observe all

instructions and precautions in

this manual.

IAWARNINGllmproper

ment

can

lead

to

and

to

damage

vice

personnel

electrical

to

and

mechanical service.

IAWARNINGI Unauthorized

placement

control emissions

of

fuel, exhaust,

system

are

components

prohibited

service

severe

personal

equipment

must

be

or

parts

injury

and

property. Ser-

qualified

to

modifications

air

intake

that

affect

by

law

in

the State

replaceor

death

perform

or

re-

or

speed

engine

of

California.

IAWARNINGI LPG

flammable

and

phyxiation. NFPA 58, Section 1.6 requires

persons handling

See cerning operation, maintenance and storage and

for

ing oil and fuel. See

mendations concerning the installation and for a list of

the installation codes and standards

which See

bers and required quantities and for exploded of

the

placement parts are recommended for best results. When

information, be ready and genset nameplate. cance of each character

Figure

are displayed on the nameplate.

handling

and

the Operator's Manual for instructions con-

recommendations concerning engine lubricat-

the Installation Manual for important recom-

may

be applicable.

the Parts Manual for parts identification num-

genset

contacting Onan for parts, service

the

serial number, both of which

1-1

for

(liquified

explosive

LPG

operating

petroleum

and

can

to

be trained

procedures.

subassemblies. Genuine

to

provide the model

appear

See

how

Table of

the

model and serial

1-1

for the signifi-

the model

gas)

cause as-

in

proper

for

safety

views

Onan®

or

product number

on

number

and

numbers

is

all

re-

the

TABLE

z

NHM

I

1

1.

Rated Power in Kilowatts

2.

Genset Family

3.

Starting Method Code

4.

Voltage and Frequency Code

5.

Options and Special Features Code

6.

Spec Letter designating modifications

2

NAMEPLATE WITH TYPICAL MODEL AND

IMPORTANT

~

Model

No.: 7NHM-FA/261 05F

SIN:

A953123456

ACVoHs: Amps: Fuel: Hz:

Insulation

- NEMA

REFER TO OPERATOR'S MANUAL FOR MAINTENANCE SPECIFICATIONS

THIS ENGINE EMISSIONS REGULATIONS FOR

SN5980U1 G2RA

FIGURE 1-1.

1-1. MODEL NUMBER

E

I

Class

MEETS

I

3

SERIAL NUMBER DATA

ENGINE INFORMATION

AND ADJUSTMENTS.

1995-1998

TYPICAL

Ph:

PI:

Ambient:

400

CALIFORNIA

ULGE ENGINES.

A

4

26105

I

ONAN CORPORATION 1400 Minneapolis, MN 55432

C

NAMEPLATE

I

5

73rd Ave. NE

Made in U.S.A.

kW:

RPM:

Bat:

12V

INI3461

980cc

E

I

6

URC

EM

1-1

Section 2. General Specifications

GASOLINE MODELS

BGM

GENERATOR: 4-Pole Revolving Field, Self-Excited, Electronically Regulated, 1-Phase Power (watts) Frequency (Hertz) Voltage Current (amperes) Speed (RPM)

FUEL CONSUMPTION: No load gph

Half load gph Full load gph

ENGINE: 2-Cylinder Opposed, 4-Cycle, Spark-Ignited, Side-Valve, Air Cooled Bore Stroke

Displacement Compression Ratio

Minimum Cylinder Compression Test Pressure

Oil Capacity (with filter)*

Intake Valve Clearance (Cold)

Exhaust Valve Clearance (Cold)

Spark Plug Gap 0.025 inch (0.64 mm) 0.025 inch (0.64 mm)

Spark Plug Tightening Torque 8 !bs-ft

Ignition Timing (Begin Spec

Ignition Timing (Prior to Spec

Maximum Fuel Supply Pressure

at Carburetor

Maximum Fuel Pump

Fuel Fitting 5/16 inch OD Hose Barb 5/16 inch OD Hose Barb

Exhaust Tailpipe Requirements

(1/h)

lift

F)

3.250 inch (83 mm) 3.563 inch (90 mm}

2.875 inch (73 mm) 3.000 inch (76 mm)

0.005 inch (0.13 mm)

0.013 inch (0.33 mm)

12° BTDC non-adjustable

14°-18° BTDC non-adjustable

1-3/8 inch

5000 6800

60

120 120

41.7

1800 1800

0.3 (1.3) 0.4 {1.5)

0.5 (1.9) 0.7 (2.6)

0.9 (3.4) 1.3 (4.9)

48 inch

75 psi (517 kPa) 75 psi (517 kPa)

3

(782 cc) 60 inch3 (980 cc}

7.0:

1

3.5 quart (3.3

(1

6 psi

(41

3 feet (0.9 m) 3 feet (0.9

ID

18 Ga Steel Tubing

I)

0.005 inch (0.13 mm)

0.013 inch (0.33 mm)

0 N-m)

12° BTDC non-adjustable

14°-18° BTDC non-adjustable

kPa)

1-3/8 inch ID 18 Ga Steel Tubing

NHM

60

56.7

7.0:

1

3.5 quart (3.3

8 lbs-ft

6 psi

(1

0 N-m)

(41

kPa)

I)

m)

CONTROL AND CRANKING SYSTEM: 12 VDC

Nominal Battery Voltage 12 volts

Minimum Battery Cold Cranking

Capacity: Above/Below Freezing

F1

Fuse

*

-See

(Control Board, Spec A only)

F2

(Fuel, Spec A only) 5 amperes slow-blow

F1

(Control Board, Begin Spec B) 10 amperes

F2

(Choke/Fuel, Begin Spec

Periodic Maintenance for oil filling instructions.

D)

360/450 amperes

5 amperes slow-blow

10 amperes mini-bayonet

LPG MODELS

NHM

GENERATOR: 4-Pole Revolving Field, Self-Excited, Electronically Regulated, 1-Phase Power (watts) 6500 Frequency (Hertz) 60 Voltage Current (amperes) 54.2 Speed (RPM)

FUEL

CONSUMPTION:

No load lbs/h (kg/h) Half load lbs/h (kg/h) Full load lbs/h (kg/h)

ENGINE: 2-Cylinder Opposed, 4-Cycle, Spark-Ignited, Side-Valve, Air Cooled Bore 3.563 inch (90 mm) Stroke Displacement Compression Ratio Minimum Cylinder Compression

Test Pressure Oil Capacity (with filter)*

Intake Valve Clearance (Cold} Exhaust Valve Clearance (Cold) Spark Plug Gap Spark Plug Tightening Torque Ignition Timing (Begin Spec F) Ignition Timing (Prior to Spec F) LPG Vapor Supply Pressure Range

(Vapor-Withdrawal Only) LPG Connection for Vapor Withdrawal

LPG Connection for Liquid Withdrawal Exhaust Tailpipe Requirements

9 to 13 inch (229 to 330 mm)

3.000 inch (76 mm)

0.005 inch (0.13 mm)

0.013 inch (0.33 mm)

0.025 inch (0.64 mm)

12° BTDC non-adjustable

o -18° BTDC non-adjustable

14

3/4 inch

1/4 inch

1-3/8 inch iD 18

120

1800

2.2 (1.0}

3.6 (1.7}

6.2 (2.8}

60 inch3 (980 cc)

7.0:

1

75 psi (517 kPa)

3.5 quart (3.3

8 lbs-ft

{1

I)

0 N-m)

W.

NPT

Tapping

NPTF

Tapping

Ga

Steel Tubing

C.

(water column)

CONTROL

!---------"'

Nominal Battery Voltage

Minimum Battery Cold Cranking I

Capacity: Above/Below Freezing

Fuse

~die

AND

CRANKING

SYSTEM: 12 VDC

~---

F1

(Control Board) 10 amperes

Mainte;;;~;~-roroil

filling

12

volts

1

amperes

450

tl

-------------~-~--,~-

~~.struction""'~s=.

=""'-""""

=""'=""-~===--·

360

~-----------;

Section 3. Dimensions and Clearances

MODELS

CYLINDERS AND PISTON ASSEMBLY

Cylinder Bore (Std size honed) (82.525-82.550 mm)

Cylinder Taper 0.005 (Max} (0.13 mm) (0.13 mm)

Cylinder Out Round (Max) (0.076 mm)

Clearance In 0.0044-0.0066 Cylinder (0.112-0.168 mm)

Ring Gap (top and 0.008-0.018 second rings) {0.20-0.46 mm)

Piston Ring Groove Width

Of

#1

(top) Spec

Spec C sets: 0.0602-0.0612

BGM NHM

(21

All clearances listed at 70° F Values are in inches (millimeters) unless specified otherwise. gensets

3.2490-3.2500

0.003

A,

B sets: 0.080-0.081

(2.03-2.06 mm) (2.03-2.06 mm)

(1

Dimensions

except

.53-1.55 mm)

as

apply

indicated.

o C) room temperature.

to

Specs

3.5625-3.5635 (90.488-90.513 mm}

0.005

0.003 (0.076 mm)

0.0070-0.0090 {0.178-0.229 mm)

0.009-0.019 (0.23-0.48 mm)

0.080-0.081

0.0602-0.0612 (1.53-1.55 mm)

A, B

and

C

Piston Ring

Groove Width

Piston Ring

Groove Width (4.78-4.80 mm)

Piston Pin 0.6875-0.6877 Diameter

Piston Pin Clearance 0.0002-0.0007 In

Rod

Connecting Rod Side Clearance

Connecting Rod Bearing Clearance (0.051-0.084 mm)

#2

#3

Spec A, B sets: 0.080-0.081

(2.03-2.06 mm)

Spec C sets: 0.0602-0.0612

(1.53-1 .55 mm) Spec A, B sets: 0.188-0.189 Spec C sets: 0.1193-0.1203

(3.03-3.06 mm)

(17.46-17.47 mm)

(0.005-0.018 mm)

0.0020-0.032 (0.051-0.813 mm)

0.0020-0.0033

0.080-0.081 (2.03-2.06 mm)

0.0602-0.0612 (1.53-1.55 mm)

0.188-0.189

(4.78-4.80 mm)

0.1193-0.1203

(3.03-3.06 mm)

0. 7500-0.7502

(19.05-19.06 mm)

0.00005-0.00055

(0.001-0.014 mm)

0.0020-0.0160

(0.051-0.406 mm)

0.0005-0.0028

(0.013-0.071 mm)

--

3-1

--------

---------'--------

---------

----

--------

MODELS

BGM

CRANKSHAFT AND CAMSHAFT

Crankshaft Main Bearing 1.9992-2.0000 Journal Diameter (50. 780-50.800 mm)

Crankshaft Rod Journal Bearing Diameter

Crankshaft Main

1 .6252-1.6260

(41.280-41.300 mm}

2.0024-2.0034

Bearing Diameter (50.860-50.886 mm) Crankshaft Main

Bearing Clearance Crankshaft End

Play Camshaft Journal

Diameter

0.0024-0.0042 (0.064-0.1 07 mm)

0.006-0.012 (0.15-0.30 mm)

1 .37 40-1.37 45 (34.900-34.912 mm)

NHM

1.9992-2.0000 (50. 780-50.800 mm)

1.6252-1 .6260 (41.280-41.300 mm)

2.0024-2.0034 (50.860-50.886 mm)

0.0025-0.0038 (0.064-0.097 mm)

0.005-0.009 (0.13-0.23 mm)

1.3740-1.3745 (34.900-34.912 mm)

Camshaft Bearing Diameter

Camshaft Bearing Clearance

Camshaft End Play

VALVE AND LIFTERS

Valve Spring Free Length { approx.)

Valve Spring Compressed Length (Valve Closed)

Valve Spring Tension

I

Open

Valve Spring Tension

Closed

1.376-1.377 (34.950-34.976 mm)

0.0015-0.0030 (0.038-0.076 mm)

0.011 0-0.0480 (0.280-1.22 mm)

1.600

1.376-1.377 (34.950-34.976 mm)

0.0015-0.0030 (0.038-0.076 mm)

.0.0030-0.0120 (0.076-0.305 mm)

1.6620

(40.640 mm) (42.214 mm)

1.3750

(34.925 mm)

71-79 lbs (9.8-1 0.9 N}

1.3750 {34.925 mm)

71-791bs

(9.8-10.9 N)

38-421bs 38-421bs

(5.3-5.8 N)

3-2

MODELS

BGM

NHM

Valve Face Angle Valve Seat Angle Valve Stem

Diameter (Intake) Valve Stem

Diameter (Exhaust) Valve Guide Intake Exhaust Intake and Exhaust

Inside Diameter

Valve Stem

Clearance (Intake) (0.025-0.064 mm) (0.025-Q.064 mm)

Valve Stem Clearance (Exhaust) (0.0508-0.0889 mm)

Valve Lifter

Diameter (18.987-18.999 mm)

Valve Lifter Bore 0.7500-0.7515

Diameter (19.050-19.088 mm)

0.281 0-0.2820 0.2805-0.2815 (7.1374-7.0739 mm) (7.1200-7.1501 mm (8. 738-8.788 mm)

0.001 0-0.0025

0.0020-0.0035

0.7475-0.7480

440

45°

0.2795-0.2800 (7.0993-7.1120 mm)

0.2780-0.2785 (7.0612-7.0739 mm)

44° 45°

0.3425-0.3430 (8. 700-8.712 mm)

0.341 0-0.3415 (8.661-8.674 mm)

0.344-0.346

0.001 0-0.0025

0.0025-0.0050 (0.064-0.127 mm)

0.7475-0.7480 (18.987 -18.999 mm)

0.7500-0.7515

(19.050-19.088 mm}

Valve Lifter To Block Clearance (0.0508-0.1 016 mm)

Valve Seat 1.4425-1.4435

Diameter (Intake) (36.6395-36.6649 mm) Valve Seat 1.192-1.193

Diameter (Exhaust) (30.28-30.30 mm) Valve Seat Bore 1 .4395-1.4405

Diameter (Intake) (36.563-36.589 mm) Valve Seat Bore

Diameter {Exhaust) 30.20-30.23 mm)

0.0020-0.0040

1 .189-1 .190

0.0020-0.0040 (0.0508-0.1 016 mm)

1.5690-1.5700 (39. 738-39.764 mm)

1.2550-1.2560 (31.877-31.902 mm)

1.5645-1.5655 (39. 738-39.764 mm)

1.251 0-1.2520 (31.775-31.801 mm)

Section 4. Torque Specifications

MODEL

TORQUE SPECIFICATIONS

Cylinder Head Bolts (cold) ConnectinQ Rod Bolts Rear Bearing Plate Flywheel MountinQ Screw Oil Base Gearcase Cover Spark Pluo Exhaust Manifold Intake Manifold Rotor Throuah-Bolt Starter Mountino Screws Stator Clamp Screws Adapter to Engine Mounting Screws Adapter to Generator Mounting Screws

Rear Vibration Isolator

Center Screw Flange to Drip Tray Screws

Front Vibration Isolator

Flange to Oil Base Screws Center Screw

Vibration Isolators

Center Screw Flange to Drip Tray Screws

Voltage Regulator

Mounting Bracket Screws 7-8 ft-lbs Regulator Attachment Screws

Start Solenoid Attachment Screws 5-6 ft-lbs

Use engine oil as a lubricant for all threads EXCEPT the spark plug and rotor through-bolt threads

FOOT-POUNDS 14'-16

12-14 25-27 34-37 50-55 68-75 20-24 27-33

10-12 7-9 9-12 9-11 6-10 8-14 45-55 61-75 30-33 41-45

10-12 11-16

25-27

25 34

30-33 41-45

10-12 14-16

19-22

28-32 38-43

30-33 ft-lbs

10-12 ft-lbs

5-6 ft-lbs

BGM

NEWTON-METERS 19-22 16-19

14-16 12-15

34-37

26-30

41-45

14-16

9-11 7-8 7-8

MODEL NHM

TORQUE Use engine oil as a lubricant for all threads

SPECIFICATIONS

Cylinder Head Nuts (cold}

(with

com_oression

Cylinder Head Nuts (cold)

(without comoression washers)

Connectina Rod

Bearing_

Rear Flywheel MountinQ Screw Starting Mounting Bracket to

Oil Base Screws

Gearcase Cover

Spark Exhaust Manifold Intake Manifold Rotor Starter Mounting Screws Stator Clarno Screws Adapter Mounting Screws Adapter to Generator MountinQ Screws

Rear Vibration Isolator

Front Vibration Isolator

Vibration Isolators

Voltage Regulator

Start Solenoid Attachment Screws

PluQ

Throu_g_h-Bolt

to

Engine

Center Screw Flanae to Drip Tray Screws

Flange to Oil Base Screws Center Screw

Center Screw Flange to Drip Tray Screws

Mounting Bracket Screws Regulator Attachment Screws

washers\

Plate

EXCEPT the spark plug and rotor through-bolt threads. FOOT-POUNDS NEWTON-METERS

14 17 27-29

25-28 50-55 20-24

10-12 7-9 20-23 14-16 45-55 30-33 10-12 25-27

25

30-33 10-12

19-22 28-32

30-33 ft-lbs

10-12 ft-lbs

7-8 ft-lbs 5-6 ft-lbs 5-6 ft-lbs

19 23 37-39

34-38 68-75 27-33

14-16 9-12 27-31 19-22 61-75 41-45

14-16 34-37

34

41-45

14-16 26-30

38-43 41-45

14-16 9-11

7-8

Section 5. Preparing for Service

TROUBLESHOOTING

See Troubleshooting to determine the probable cause of the problem before removing the genset for service.

SAFETY

There are hazards in servicing gensets. Study Safety Precautions and become familiar with the hazards listed in Table guards and ways of avoiding hazards:

• Use

personal

protective safety equipment, such as: Safety shoes Gloves Safety glasses Hard hats Do not wear rings or jewelry and do not wear

loose clothing that might get caught ment.

5-1

. Note the following safe-

protection:

Wear appropriate

in

equip-

• Reduce the hazard: A safe, orderly workshop

area and well-maintained equipment reduce the hazard potential. Keep guards and shields in place on machinery and maintain equipment in

good working condition. Store flammable liq-

uids

in

approved containers; away from fire, flame, spark, pilot light, switches, arc-producing equipment and other ignition sources.

Keep the workshop clean and well-lighted and

provide adequate ventilation.

• Develop safe

cause accidents with tools and machines. Be familiar with the equipment and know how to

use it safely. Use the correct tool for the job and

work

habits: Unsafe actions

check its condition before starting. Comply with the warnings in this manual and take special precautions when working around electrical equipment. Do not work alone if possible and take no risks.

•

Be

prepared

guishers and safety equipment nearby. Agencies such as the Red Cross and public safety departments offer courses fire control. Take advantage of this information to be ready to respond to an accident. Learn to be safety-conscious and make safety proce-

dures part of the work routine.

TABLE 5-1. HAZARDS AND THEIR SOURCES

Fire

and

Explosion

Burns

Poisonous

Gas

Electrical • Faulty wiring

Shock

Machinery

(AC)

Rotating

Slippery

Surfaces

Heavy

Objects

for

an

accident: Keep fire extin-

in

first aid, CPR and

• Leaking or spilled fuel

• Hydrogen gas from battery

• Oily rags improperly stored

• Flammable liquids improperly stored

• Hot exhaust pipes

• Hot engine and generator sur-

faces

• Electrical shorts

• Operating genset where exhaust gases can accumulate

• Improper generator connections

• Working in damp conditions

• Jewelry components

• Fan guards not in place

• Leaking or spilled oil

• Removing genset from vehicle

• Removing heavy components

touching electrical

SPECIAL TOOLS

Valve seat cutter kit

The

tools listed below are necessary for servicing

the genset. See the Onan Tool Catalog.

Engine Tools

Torque wrench: 0-75 lbs-ft (0-1 Hole gauge: 0.300-0.400 inch (5-1 0 mm) Outside micrometer set: 0-4 inch (0-1 Telescoping gauge set: up

Feeler gauge

Plasti-Gage bearing clearance guide Spark plug gap gauge Oil pressure gauge: 0-30 psi (0-200 kPa)

Fuel pressure gauge (for gasoline): 0-10 psi

(0-75 kPa)

Manometer (for LPG):

Inclined Manometer (for LPG): 1 inch (25

14

00

N-m)

to

4 inch

inch (350

we range with 0.01 inch (0.2 mm) we di-

visions Cylinder compression tester Flywheel puller

00

(1

00

mm)

WC

mm)

Valve guide driver

hammer

Slide Lead

or

dead-blow

hammer

Generator and Control Tools

Rotor removal tool (headless bolt) Battery hydrometer Frequency meter

AC

Digital multi-meter:

and Diode

Loadtestpanelandleads

Voltage Regulator Testor and Adaptor (1-Ph)

Rotor and Stator Testor and Adaptor

Check

and DC Voltage,

Ohms

REMOVING THE GENSET

Some set be removed from mally mounted in a special compartment on hicle floor. Because installations vary, it is not possible tact way

service procedures will require that the gen-

the

vehicle.

to

describe a specific removal procedure. Con-

the

vehicle manufacturer

to

remove

the

genset is not obvious.

The

genset is nor-

or

installer if the best

the

ve-

Crankshaft gear puller ring, bolts and puller

(or special shoulder bolts and flywheel

puller) Snap ring pliers

cam

Combination main and Combination main and Oil seal loader and driver Cylinder ridge reamer Piston ring spreader Piston groove cleaner

bearing remover

cam

bearing driver

Piston ring compressor

Cylinder hone Valve spring compressor Valve lock replacer

Disconnections at the Genset

1.

First disconnect the negative (-) battery cable

from the battery and then disconnect the bat-

tery cables from the genset.

IAWARNINGI Sparks

cause fire battery cables of

cables connected to the battery touch.

Always

and

other and

disconnect cable from the battery before disconnecting

the battery cables from the genset.

2. Disconnect

connector at the genset.

3.

Disconnect the generator output wiring and conduit from the povver distribution panel

box

on

the

remote control wiring harness

the all wires to make re-

connections easier.

5-2

and

high

current

damage

vehicle

to

if

the loose ends

the negative

could

the battery,

(-)

battery

or

4.

Disconnect the exhaust tailpipe from the outlet of the muffler. See EXHAUST SYSTEM under

6.

Section

5.

Disconnect the fuel supply line from the gen-

set. Follow the applicable instructions depend-

ing on the fuel.

I A

WARNING

troleum gas) are flammable and death. Do oline equipment tion sparks, producing of

ignition

Gasoline Fueled Gensets:

fuel line from the genset and securely plug the end of the fuel line cumulation of explosive gasoline vapor.

Engine-Primary Systems.

I Gasoline

and

can cause severe

not

or

are

with

pilot

smoke

near

or

are

such

lights, equipment well

if

you

fuel

tanks

in

an

equipment. Keep flames,

electrical

and

away.

to

prevent leakage or an ac-

LPG

and

personal

smell

or

area

sharing

all

other

Disconnect the

(liquified

explosive

injury

gas

or

fuel-burning

ventila-

arcs

and sources

LPG Fueled Gensets: Close the fuel shutoff

valve(s) at the LPG container(s) and move the vehicle outside and away from below-grade spaces where LPG could accumulate. purge the fuel line and genset as much as possible, run the genset (if of fuel with the LPG valve(s) closed. Also see the specific additional instructions which follow for purging liquid-withdrawal and vapor-withdrawal systems and for capping off the gas

supply line.

IAWARNINGI LPG

sive

and

can cause asphyxiation. NFPA 58, Section 1.6 requires LPG

to

be

trained

it starts) until it runs out

is

flammable

all

persons

in

proper

and

handling

operating procedures. LPG

and

"sinks" can

when

it

accumulate

escapes

in

explosive

into

the

pe-

or

gas-

arc-

To

explo-

and

air

con-

centrations. Before fuel line,

close the LPG container(s) outside other could

Purging LPG Liquid-Withdrawal Systems (See

Figure 6-25 On Page 6-29): Purge the supply

line further by loosening the threaded supply connection at the LPG filter on the genset just enough to hear gas escaping. Unthread the connector when no more gas is heard escaping. lenoid and regulator, loosen the flexible hose

connector at the fuel solenoid just enough to hear gas escaping, and then retighten. Finally, cap the end of the fuel supply hose or pipe with a 1/4 inch NPTF pipe cap to prevent fuel from escaping shutoff valve(s) at the LPG container(s).

IOAWARNINGI

released

and

away

below-grade spaces where LPG

accumulate.

To

purge the LPG trapped between the so-

if

someone inadvertently opens the

Large volumes

in

the liquid-withdrawal type tem. Before

disconnecting nections, make valve(s) and from

at

the LPG container(s) are

that the vehicle

pits

or

grade spaces where LPG

disconnecting

the

fuel

shutoff

and

from

pits

process

of

sure

the the fuel

is

basements

the LPG

valve(s)

move

the vehicle

or

basements

of

LPG

disconnecting

LPG

supply

LPG

fuel

shutoff

outside

or

other

could

and

accumu-

at

or

can

be

sys-

con-

closed

away

below-

a

late.

Purging LPG Vapor-Withdrawal Systems (See Figure 6-29 On Page 6-32): Disconnect the

gas supply hose at the carburetor and the fuel solenoid shutoff valve leads at the control box on the genset. If the pressure regulator/solenoid valve assembly is also to be removed, cap the end of the fuel supply line with a threaded pipe cap to prevent fuel from escaping one inadvertently opens the shutoff valve(s).

if

some-

5-3

Removal

See Figure 5-1. When the genset has been disconnected from the electrical, exhaust and fuel systems, examine its mounting bolts and support members. The genset drip tray is normally bolted to the vehicle framework. Make sure that the genset

firmly supported before loosening any mounting

of

the

Genset

from

the

Vehicle

is

bolts or support members. A fork lift is recommended to lift or move the genset.

IJiwARNINGI

severe or

other

while removing

feet clear incase the

Gensets are

personal

injury

suitable means

or

installing

heavy

if

dropped. Use a

to

handle the it. Keep hands

genset

is

dropped.

and

can cause

forklift

genset

and

FIGURE 5-1. SET REMOVAL

5-4

Section 6. Engine - Primary Systems

The engine primary systems and service procedures covered

in

this section do not require removal

of the cylinder heads, gearcase or rear bearing

refer to Manual for instructions heads using Onan "4C".

Periodic Maintenance in the Operator's

on

how to clean the cylinder

plate for access. It may be possible to perform some of these procedures without removing the genset from the vehicle.

The following troubleshooting tables are designed

To

to help you think through genset problems.

save time troubleshooting, read the entire manual ahead of

TROUBLESHOOTING ENGINE PRIMARY

SYSTEMS

time to understand the genset. Try to think through problems. Go over what was done during the last service call. The problem could be as simple as an empty fuel tank, closed fuel shutoff valve,

Regular maintenance can prevent many of the

loose wire, blown fuse or tripped circuit breaker.

problems listed below. Removing and cleaning the cylinder heads every 500 hours is especially impor- See

Section

7.

Control System and Section

B.

Gen-

tant for gasoline models. Before considering major erator for control and generator troubleshooting

engine service because of abnormal performance, tables.

I A

WARNING

injury

or

hazards

Trouble Possible Cause Corrective

Engine Misfires

I

Many

death.

should

troubleshooting

Only

qualified

perform

1.

Faulty ignition due to: a.

worn

b.

faulty ignition coil.

c.

faulty plug wires.

service

service procedures. Review

or

fouled spark plugs.

procedures

personnel

present

with

hazards which

knowledge

safety

precautions

can

result

of

fuel, electricity,

on

inside

Action

1 a. Replace spark plugs. 1

b.

Test coil and replace if necessary.

1c. Test spark plug wires and replace

if faulty.

in

severe

and

cover

personal

machinery

page.

2.

Lean fuel mixture due to: a.

b. c. d. e.

3.

Contaminated fuel.

4.

Carburetor icing.2

Engine Backfires

1.

Faulty ignition due to

incorrect spark plug gap.

2.

Lean fuel mixture due to:

a. b.

c.

3.

Mechanical

1 - Prior to

2 - Gasoline models only

Spec

F only

incorrectly adjusted fuel mixture screws.1 incorrect float level.1· 2

dirt

in

carburetor.

vacuum leak.

altitude setting.

2

incorrectly adjusted fuel adjustment screws.1 incorrect float level.1 · 2 dirt

in

carburetor.

damage

to

engine.

2a. Adjust carburetor main

and idle adjustment screws.

2b. Adjust carburetor float level.

1 1

2c. Disassemble carburetor and clean all

1

internal passages.

Replace fuel filter. 2d. Locate leak and correct as required. 2e. Reset altitude adjust knob on carburetor.

3. Drain fuel tank and refill with fresh fuel.

4. Place air preheater

1.

Reset spark plug gap.

in

winter position.

2a. Adjust carburetor main and idle

mixture screws.1

2b. Adjust carburetor float level.

1

2c. Disassemble carburetor and clean

all internal passages.

3.

See

Engine

Block

1

Assembly

section.

TROUBLESHOOTING ENGINE PRIMARY SYSTEMS

lA

WARNING I Many troubleshooting procedures present hazards which can

injury hazards

or

death. Only

should

qualified

service personnel with knowledge

of

perform service procedures. Review safety precautions

result

in severe personal

fuel, electricity,

on

inside

and

cover

machinery

page.

Trouble

Engine Lacks Power

Possible Cause

1.

Faulty ignition due to incorrect

spark plug gap.

2.

Dirty air cleaner.

3.

Restricted fuel flow due to: a.

Plugged fuel filter.

b.

Faulty fuel pump.

4.

Incorrect fuel mixture due to: a.

incorrectly adjusted fuel mixture screws.1

b.

incorrect float level.1, 2

c.

dirt

in

carburetor.

d.

vacuum leak.

e.

altitude setting.

5.

Exhaust system blocked or

restricted.

6.

Incorrect valve tappet clearance.

Corrective Action

1.

Reset spark plug gap.

2.

Replace air cleaner.

3a. Replace fuel filter. 3b. Test fuel pump and repair or replace

if faulty.

4a. Adjust carburetor main and idle

adjustment screws.1 4b. Adjust carburetor float level. 4c. Disassemble carburetor and clean all

internal passages. 4d. Repair vacuum leak. 4e. Reset altitude adjust knob on carburetor.

5.

Locate and remove cause of blockage.

6.

Adjust valve tappets (see Engine Block

Assembly

section).

1

Replace fuel filter.

1

7.

Excessive engine wear or

8.

Carburetor air preheater set

9.

Combustion chamber deposits.

10.(Spec A sets) No-ioad speed 10. Adjust (mechanical) governor.

11.Contaminants

1 - Prior to Spec F only 2 - Gasoline models only

damage to engine.

incorrectly.

set too low: excessive governor droop.

(liquid-withdrawal systems}

2

in

LPG regulator. 1

6-2

7.

See Engine Block Assembly section.

8.

In

hot weather, place air preheater

summer position.

9.

Clean combustion chamber.

11.

Clean LPG regulator.

in

TROUBLESHOOTING ENGINE PRIMARY SYSTEMS

I

.A

WARNING I Many troubleshooting procedures

injury hazards

or

death.

should

Only

qualified

perform

service

personnel

service procedures. Review

present

with

knowledge

safety

hazards which can

of

fuel, electricity,

precautions

result

on

inside

in

severe

and

cover

personal

machinery

page.

Trouble

Engine

Overheats

Possible Cause

1.

Restricted airflow due to: a. b.

2. Dirt or oil covering engine

cooling fins.

3.

Lean fuel mixture due to: a.

b. c. d. vacuum leak.

Black Exhaust Smoke

White or Blue Exhaust Smoke

1.

Rich fuel mixture a. b.

1. Lean fuel mixture due to:

a. b.

c. d. vacuum leak

2. Contaminated fuel.2

3.

Excessive engine wear

1 - Prior to Spec F only

2 - Gasoline models only

debris blocking air inlet improper installation

incorrectly adjusted fuel mixture screws.1 incorrect float level. dirt in carburetor.

due. incorrect float level faulty carburetor float.1 · 2

incorrect float level. 1 • 2 incorrectly adjusted fuel mixture screws.1 dirt

in

carburetor

1.

to:

or

2

outlet

Corrective Action

1.

a.

Clear away debris. Do not use genset

compartment for storage.

b.

See the Installation Manual.

2. Clean away all dirt and oil from engine

cooling fins.

3.

a.

Adjust carburetor main and idle adjustment screws. 1

3.

b.

Adjust carburetor float level.

c.

Disassemble carburetor and clean all internal passages.1 Replace fuel filter.

d.

Repair vacuum leak.

1

a.

Adjust carburetor float level.

1

b.

Replace carburetor float.

1

a.

Adjust carburetor float level.

1

b.

Adjust carburetor idle and main adjustment screws.1

1

c.

Disassemble carburetor and clean all internal passages.

1 d. Repair vacuum leak.

1

2. Drain and replace fuel.

3.

See Engine Block Assembly section.

6-3

TROUBLESHOOTING ENGINE PRIMARY SYSTEMS

lA

WARNING 1 Many troubleshooting procedures

injury hazards

or

death.

should

Only

qualified service personnel with knowledge

perform

service procedures. Review

present

safety

hazards which can

of

fuel, electricity,

precautions

result

on

inside

in

severe personal

and

machinery

cover

page.

Trouble

Engine Surges

Possible Cause

1.

Sticking or binding

(mechanical) governor linkage.

2.1ncorrect (mechanical) governor adjustment.

3.

Faulty (mechanical) governor

spring.

4. Incorrect fuel mixture due to: a.

incorrectly adjusted

fuel mixture screws.1

*

b.

incorrect float level.1. 2

c.

dirt in carburetor

d. ignition misfires

5. Intermittent electrical connections.

6. Governor mechanism worn excessively.

Corrective Action

1.

Clean governor linkage (remove dirt or ice buildup). Check that linkage does not touch other parts.

2. Adjust governor speed and sensitivity.

3.

Replace governor spring.

4a. Adjust carburetor main and

idle adjustment screws. 4b. Adjust carburetor float level. 4c. Disassemble carburetor and

clean all internal passages.1 4d. Check connections, see Ignition

section.

5.

Check battery and ignition connections.

6.

See Engine Block

Assembly section

..

1

7.

Fuel supply problem caused by: a. b. c. d. Plugged fuel filter

8. Carburetor icing.

1 - Prior

2 - Gasoline models only

to

Spec F only

Faulty fuel pump. 2 Contaminated fuel supply. 2 Vapor locking. 2

2

7a. Check fuel pump and replace

if defective. 7b. Drain and refill fuel supply 7c. Check for cause of overheating 7d. Replace fuel filter.

8. In cold weather, place

preheater in winter position.

air

TROUBLESHOOTING ENGINE PRIMARY SYSTEMS

lA

WARNING I Many troubleshooting procedures present hazards which can result

injury hazards

or

death.

should

Only

qualified service personnel with knowledge

perform

service procedures. Review safety precautions

of

fuel, electricity,

on

in

inside

severe personal

and

machinery

cover

page.

Trouble Possible Cause

High Oil

1.

Oil viscosity is too light .

Consumption

(Note: New engines sometimes dirty consume during

oil

break-in)

Low Oil

2. Crankcase breather valve is or

faulty.

3.

Oil leaks.

4.

Excessive engine wear.

5.

Light loading.

1.

Oil viscosity is too light.

Pressure

2.

Oil dilution due to: a. faulty choke b.

fouled spark plug

c.

rich fuel mixture

Corrective Action

1.

Drain and refill with oil suitable for the ambient temperature.

2.

Clean crankcase breather and replace if defective.

3. Locate source of leak and repair as required.

4.

See Engine Block Assembly section.

5.

Don't run set

at

no-load

for long periods of time.

1.

Drain and refill with oil suitable for

the ambient temperature.

2.a. Adjust choke. b. Replace spark c.

Adjust fuel mixture · 2

plu~s

3.

Low oil level.

4. Low oil pressure switch defective.

5.

Faulty oil bypass valve.

6.

Excessive engine wear or faulty oil pump.

1 - Prior to Spec F only

2 - Gasoline models only

3.

Add oil as required.

4.

Replace oil pressure switch

(see Engine Block Assembly section).

5.lnspect oil bypass valve and clean or replace as required

(see Engine Block Assembly section).

6.

See Engine Block Assembly section.

6-5

EXHAUST SYSTEM

See Figure 6-1. The exhaust system consists of the exhaust manifold, muffler, tailpipe adapter and tailpipe. The muffler is mounted inside the genset housing. The tailpipe is supplied by the customer.

of

LPG, disconnect both ends tubing clamped to the manifold. Remove the four exhaust manifold bolts and then the manifold and gaskets. Be sure to cover the openings in the block

to

prevent loose parts and dirt from entering the engine.

of

the LPG vaporizer

lA wARNlNG!

system gine

exhaust

Liability expense due

fler

or sponsibility proved

Use Onan

Repair the exhaust system before running the gen-

if there is damage

set broken or leaky tailpipe, muffler

Exhaust

must

not

away

for

injury, death, damage

to

due

to

of

muffler

approved

gas

leak

and

from

the use

of

modifications

the

person

or

performing

exhaust

or

leaks. Do not try to weld a

is

deadly. The

must

discharge

the vehicle.

and

an

unapproved becomes the re-

installing

the modifications.

system

or

parts.

manifold.

exhaust

all

en-

warranty

muf-

the unap-

Tailpipe

If it is necessary to replace the tailpipe, use 1-3/8

I.

D.

j8

inch pipe is connected rigidly to the engine (via the muffler) and the engine tors, flexible shock-mount hangers must be used support the tailpipe. Important safety warnings and instructions regarding the routing and termination the tailpipe are included in the Installation Manual.

gauge steel tubing. Because the tail-

is

mounted on vibration isola-

to of

IAWARNINGI

can weaken

ing

LPG

ing

in

possible

Large volumes

process

type

of

paring

Bending

it

to

the

under

high

severe

of

disconnecting

LPG

supply

to

Service

the

fuel

vaporizer

point

that

it

can

crack

pressure

personal

LPG

can

to

escape, result-

injury

be

released

a liquid-withdrawal

system. See Section

for

proper

procedures

tubing

allow-

or

death.

in

5.

the

Pre-

and

precautions.

When installing an exhaust manifold, always use

new

gaskets and torque the manifold bolts accord-

ing to

Section

ifold has an LPG vaporizer tube clamped nect the tubing ends before tightening the manifold bolts. Also, if necessary, loosen

to

make the tubing connections easier and then re-

tighten the clamps.

EXHAUST

MANIFOLD

4.

Torque Specifications. If the man-

to

the

tubing clamps

MUFFLER

ATIACHMENT

FLANGES

MUFFLER

it, con-

-~

Muffler

It will probably be necessary from the vehicle. See

vice.

Remove the this section). Then remove the two flange bolts the joint between the manifold and the muffler and the four mounting bracket screws on the ends

muffler and withdraw the muffler. When installing the muffler make sure the

aligning joint between the manifold and the muffler

lines up properly for a leak-free joint before tighten-

ing the bracket mounting screws.

Exhaust

To

remove the exhaust manifold first remove

muffler. On gensets equipped

top

Manifold

Section

panel (see COOLING SYSTEM in

to

remove the genset

5.

Preparing to Ser-

for

liquid-withdrawal

of

the

self~

the

6-6

MUFFLER SUPPORT

FIGURE 6-1. EXHAUST SYSTEM

BOTTOM-EXIT

TAILPIPE

ADAPTER

TAILPIPE

COOLING SYSTEM

See Figure 6-2. These are air-cooled gensets. The

engine flywheel is also a centrifugal blower that draws cooling air across the fins on the engine cylinders and heads and discharges the warm air downwards through the discharge grill.

IAWARNINGI Do

all

the covers flywheel. can result death.

not

run the generator

in

place. Contact with the rotating

in

severe personal

set

injury

without

or

lAWARNINGI

include deadly exhaust gas. Therefore, use engine discharge the vehicle.

See the Installation Manual regarding the minimum

free area required for the air inlet to the compart-

ment

or quired at the discharge opening. The engine will overheat if the inlet and outlet openings are too small or are obstructed on the cooling fins.

Discharge

enclosure and the minimum clearance re-

air

from the engine can

do

air

to heat the

or

if dust has accumulated

interior

not

of

AIR

OUTLET

FIGURE 6-2. COOLING AIR FLOW

6-7

BOTTOM

'~

AIR

INLET

Cooling System Panel Removal

1.

Disconnect the starting battery, negative (-) cable first, to prevent accidental starting.

2.

Pry off the trim strips (if any) around the three sides of the top panel and remove the exposed

Torx screws and the two screws

on Figure 6-3. Through the spark plug access opening, unhook the left-side (oil filter side) spark plug lead from the top panel and remove

the panel.

3.

Remove the left and right side panels. Five remaining Torx screws and two capscrews at the top of the cylinder heads secure each.

------~---~

top. See

4.

Remove the end panel which is secured by four remaining screws along its bottom edge.

Cooling System Disassembly for Engine Block Service:

1.

Remove the cooling system panels, muffler and exhaust manifold (see EXHAUST SYS-

in

TEM

2.

Remove the flywheel. See Flywheel Removal.

3.

Disconnect the lead connected at the low oil

this section).

pressure cutoff switch (next to the oil filter).

4.

Remove the four capscrews that secure the in-

ner bulkhead to the engine and remove

5.

Thoroughly clean the engine cooling fins.

it.

TRIM

STRIP*

SIDE PANEL

STRIP*

--------...

RIGHT

TRIM

TOP PANEL

~

INNER

BULKHEAD

TRIM

STRIP*

END

PANEL

SIDE PANEL

FIGURE 6-3. COOLING SYSTEM

6-8

*SPEC

A ONLY

Flywheel Removal

Cooling

System

Reassembly

1.

Loosen the flywheel capscrew and back it out several turns. See Figure 6-4.

2. Attach the puller tool to the flywheel. The tool has two jack screws that fit into the holes tapped in the flywheel. Tighten the puller center screw until the flywheel comes loose. Remove

-the puller, flywheel center screw and washer. Inspect the flywheel and replace it if any air vanes are missing.

FLYWHEEL

/

FLYWHEEL

PULLER

Reassembly is the reverse of disassembly.

1.

Make sure the woodruff key is in place when installing the flywheel. Use non-hardening sealer on the flywheel capscrew threads and tighten according to

cations.

2.

Make sure the pieces of insulation used to seal the openings in the inner bulkhead where the two muffler support brackets and the exhaust manifold pass through are in place.

3.

Make sure the lead to the low oil pressure

switch has been reconnected.

lA CAUTION I Running_the

oil

pressure

to

low

serious

oil

pressure.

lead

of

4.

Make sure the spark plug cable (oil filter side) has been rehooked by the clip inside the top panel to prevent it from interfering with the governor rod and causing erratic operation.

Section

set

cutoff

switch

engine damage

4.

Torque Specifi-

without connected can

in

the event

the

low

FLYWHEEL

CAP SCREW

FIGURE 6-4. FLYWHEEL PULLER

lA CAUTION! The engine

damaged system

if

it

is

operated

components

in

will

overheat

without

place.

all

and

the

can

be

cooling

IGNITION SYSTEM

These gensets are equipped with an electronic ignition system consisting of a rotor, module, coil, capacitor, spark plugs and associated wiring. Energy for ignition is supplied by the 12 volt cranking bat-

tery.

Rotor

ENGINE-GENERATOR

ADAPTOR

IGNITION MODULE

See Figure 6-5. gine crankshaft. polarity (north and south). One pole switches on the ignition module and the other pole switches it off, once each revolution of the crankshaft. should not normally require replacement.

The

ignition rotor is keyed to the en-

The

ends have opposite magnetic

The

rotor

Module

The

ignition module is secured and grounded to the

by

two

generator-engine adaptor an electronic switch in the primary circuit tion coil. See

appropriate wiring diagram. It is switched on and off

once each revolution by the rotor. The module contains no serviceable parts and should not normally

require replacement.

Section

11.

Wiring Diagrams for the

cap screws. It is

of

the igni-

Coil

See Figure 6-6. that fires the spark plugs

each revolution when the ignition module opens the

primary circuit causing the coil field

The

ignition coil is a transformer

at

roughly 20,000 volts

to

collapse.

FIGURE 6-5. IGNITION ROTOR AND MODULE

HIGH VOLTAGE

TERMINALS

lA CAUTION I The leads connected

of

the

age terminals

should

high

not

be routed

voltage terminal posts. Otherwise, false

signals can be induced in the

to

leading

erratic operation.

ignition

so

as

to

at

the

coil

(Figure 6-6)

pass

between the

low

voltage wires,

Capacitor

The

ignition capacitor is secured and grounded to the top of the generator-engine adaptor screw. low voltage terminal

The

pig tail is connected to the positive ( +)

of

the ignition coil.

by one cap

low

volt-

PRIMARY WINDING

FIGURE 6-6. IGNITION COIL

6-10

Spark Plugs

Quick

Ignition

Test

The genset has two spark plugs. The spark plugs

QOOd

must be in

for top engme performance. See Figure 6-7 and

Section 2. General Specifications.

To

prevent crossthreading a spark plug, always

thread it

sp~rk

cations. Alternatively, turn it with a wrench an addi-

tional1/4

If the engine misses or performance otherwise de-

teriorates, remove and examine the spark plugs for

signs of the following problems:

Light One

low cylinder compression

Soot

cold), duty cycle too short for engine to reach normal operating temperature

Fuel

cold), faulty choke operation, overly rich fuel mixture, dirty air filter

Oil

worn rings, worn valve guides or seals '

Burned

gaskets, lean fuel mixture

Worn

in

plug according to Section

turn.

tan,

s~ark

fouled

Or

-Spark

condition and have the proper gap

by

hand until it seats. Then tighten the

4.

Torque Specifi-

gray

or

plug

reddish

foule~-

deposits

Broken spark plug cable,

- Normal

- Wrong spark plug heat range (too

- Malfunctioning crankcase breather

Overheated-

plug service life used up.

Leaking intake manifold

If the engine misfires, test the ignition system as follows to quickly determine if the problem is in the ignition system. First recheck, clean and tighten the

at

connections

tion

11.

Wiring Diagrams for the proper connections

at

the "-!' and "+" terminals.

IAWARNINGI

and

explosive injury lated door

you

or

area, leave the

open

cannot conducting tinguisher

1.

Park the vehicle in a well-ventilated area, leave

the generator compartment door open for sev-

eral minutes and make sure you cannot smell

gas

test.

2. Remove one of the spark plugs.

3.

Reconnect the spark plug cable and lay the

spark plug on bare engine metal to ground it.

IAWARNINGI

electric

or

wire

4. Crank the engine and observe the spark. A strong, tion system is probably functioning properly and that the problem is elsewhere. See Trou- bleshooting. Service the ignition system as required if the spark is weak or inconsistent.

the ignition coil terminals. See Sec-

Gasoline

death.

for

smell

this

and

Park

several

test. Have

and

can

cause severe

the vehicle

generator

minutes

gas

or

LPG are flammable

personal

in

a well-venti-

compartment

and

make

gasoline

an

vapors

ABC

rated fire ex-

before

handy.

or

gasoline vapors before conducting this

HIGH VOLTAGE.

shock

during

consist1~nt

do

not

touch

this

test.

spark indicates that the igni-

the

To

prevent

spark

sure

plug

FIGURE 6-7. CHECKING SPARK PLUG GAP

Spark Plug

Remove both spark plug cables and check resistance across the ends with an ohmmeter. Replace a cable

if resistance is not between 3,000 and 15,000

ohms.

Cabh:!

Resistance Test

6-11

Ignition Module Test

1.

~emo~e

tion the crankshaft

IAWARNINGI Severe

can

ly

rotating the crankshaft. ing cables from the

2. Connect the positive ( the negative (larger of the two screw terminals} and the negative ground.

3. Remove ali leads from the positive(+) terminal

of

the coil.

4.

~sea

tion module (the one just removed from the coil) to the battery positive(+) terminal.

5.

Rotate the engine clockwise using a socket head wrench (either a 3/8 inch Allen orTorx) the generator through bolt. Replace the ignition

module mately then back again, each revolution.

both spark plug cables from the igni-

c01l

so

that the engine cannot start when

is

manually rotated.

persontll

result

during

if

the engine

this

test, remove

ignition

+)

(-)

terminal of the ignition coil

(-)

side of the voltmeter to engine

jumper to connect the

if

voltage does not jump from approxi-

1 volt to approximately 12 volts, and

injury

starts

while manual-

To

prevent

both

spark

coil.

side of a voltmeter to

red

lead of the igni-

or

death

start-

plug

on

ners around the high tension terminals: these indicate electrical leakage. Replace a damaged or leaking coil.

4.

Clean the outside of the coil with a cloth damp-

in

ened

5.

Measure primary coil resistance (across the positive[+] and negative[-] terminals). Replace the ignition coil tween

parts cleaning solvent.

if

primary resistance is not be-

3 and 5 ohms.

6. Measure secondary coil resistance (across the

~park

tion cotl1f secondary resistance

14,000 and 30,000 ohms. See Figure 6-8.

~l~g

cable terminals). Replace the igni-

is

not between

Ignition

1.

2.

3.

Coil Test

Remove all wires attached to the ignition coil.

Remove the coil from the engine.

Inspect the terminals for corrosion, looseness, cracks or other damage. Look for carbon run-

FIGURE 6-8. TESTING THE IGNITION COIL

6-12

CYLINDER COMPRESSION TEST

Examining the spark plugs and testing cylinder

compression can tell much about the condition of

valves, piston rings and cylinders. Test cylinder

the compression as follows:

1.

Start the genset and let it warm up.

2. Stop the genset and spark plugs. See IGNITION SYSTEM in this section.

remove and inspect the

14wARNINGI

flammable burns mended

Reassembly:

Replace the reed the discharge orifice. Torque the

12-241bs-in (1.3-2.6 N-m).

14

CAUTION! Over-tightening the

distort gine.

Most

parts

and

corrosive

and

inflammation. Use

by

the manufacturer.

Reassemble using a new gasket.

valve if it does not lie flat across

the

cover

allowing

cleaning

and

dirt

solvents

can cause severe

only

as

cover capscrew to

capscrew

to

enter

are

recom-

can

the en-

3. Insert the compression gauge nozzle into one of the spark plug holes, hold the throttle open and crank the engine. Note the pressure indicated

4.

5.

by

the gauge. Repeat the test on the other cylinder. Refer to Section

cylinder compression test pressures do not

Specifications.

meet

9.

Engine Block Assembly if

CRANKCASE BREATHER ASSEMBLY

See Figure 6-9. The crankcase breather is a reed

valve assembly that opens to discharge crankcase

vapors on the piston down-stroke and closes on the

up-stroke, resulting crankcase when the engine is running. The crankcase vapors (blowby gases, gasoline vapors, mois-

ture, air) are routed to the carburetor for burning in

the cylinders. A dirty or sticking leaks, high oil consumption, rough idle, reduced engine power and sludge formation within the engine.

in

a negative pressure in the

valve can cause oil

BREATHER

HOSE

FLAT

WASHER

FLAT

WASHER

Ill

~

~~

HOSE

CLAMP

/

VALVE

COVER

PACK

GASKET

Disassembly: The breather assembly is serviced

by disassembling it and cleaning all the parts parts cleaning solvent. The assembly comes apart when the capscrew is unscrewed.

in

REED

~#'

-

VALVE

FIGURE 6-9. CRANKCASE BREATHER ASSEMBLY

6-13

BREATHER

BAFFLE

GOVERNOR AND CARBURETOR

ADJUSTMENTS

The governor operates the throttle nearly constant engine speed (frequency) as the electrical load on the genset varies. Careful adjustments of the carburetor and governor are essential for top performance. Perform all necessary engine and generator maintenance and repairs before making these adjustments.

to

maintain a

VCRs, tronic buretor

circuits

vices are

switched aged

occur

computers

and

devices before making

adjustments. Typically, some internal are

powered

plugged

in, even

"OFF". These

by

variations

during

in

these tests.

Electronic Governor

other

solid-state elec-

governor

when these types

if

the device has been

circuits

voltage

and

frequency

can

and

of

be

car-

de-

dam-

that

Governor and carburetor adjustments should be done together. They require the use of meters to measure voltage, frequency and amperage and a

kW,

.stepped load bank of at least 8

of at least 600 watts is variable. Digital meters are

recommended. Accuracy should be at least 0.3 percent for frequency measurement and 0.5 percent for voltage measurement.

Beginning ing screws are not accessible. Other than turning the altitude adjust knob to compensate for altitude

on

gasoline carburetors, fuel mixture adjustments

should not be attempted.

IAWARNINGI Unauthorized

placement

control

emissions are

Spec

F,

carburetor fuel mixture adjust-

of

fuel, exhaust,

system components

prohibited

by

where a portion

modifications

air

intake

that

law

affect

in

the

or

State

or

re-

speed

engine

California.

IAWARNINGI Disconnect

and

frequency sensitive devices

or

unplug

such

all

voltage

as

TVs,

of

Electronic are

not

age (Figure top panel. The governor controller is mounted on the base pan (Figure 7-5).

Disconnecting

top panel (see COOLING SYSTEM in this section) for access to the governor rod. Unhook the gover-

nor rod and spring from the governor actuator arm first. Use both hands so as not to bend the actuator

arm. Then unhook the rod and spring from the throttle.

governor

adjustable. The governor actuator and link-

6-1

speed

0)

are accessible by removing the

and

sensitivity

set

points

the Governor Rod: Remove the

Reconnecting the Governor Rod: Before recon-

necting the governor rod check to see the the paint

seal

on

the throttle stop screw not been broken. If it has been broken, readjust the throttle stop screw as follows:

1.

Disconnect the governor rod from the actuator

arm if it has not already been removed.

on

the carburetor has

ACTUATOR

LEVER

GOVERNOR

ACTUATOR

GOVERNOR

ROD

FIGURE 6-10. ELECTRONIC GOVERNOR

6-14

1

SPRING

/

UNKAGE

2. Loosen the throttle stop screw locknut and back the screw out away from the tang on the throttle lever, while gently rotating the throttle

lever counterclockwise as far as if will go.

For

LPG Gensets: Turn the idle mixture screw

out 1-1/4 turns and the main fuel mixture screw

out 2-1/2 turns

so

that the engine will start and

run.

3. While gently holding the throttle lever counterclockwise as far as it will go, turn the stop screw in until it just touches the tang. Then turn the screw an additional 118-1/4 turn (clockwise)

and set and seal the locknut.

If the throttle stop screw adjustment is okay, reconnect the governor rod as follows:

1.

Insert the rod in the spring such that the shorter

hook wire is on the throttle side.

2. Hook the rod and spring into the grommet in the throttle lever. (The spring should pull on one side and the rod push on the other side

of

the

grommet when fully assembled.)

3. Pull the governor rod towards the plastic clip on the end of the actuator lever as far as the throttle stop screw permits. Leave the actuator

lever in its fully counterclockwise (rest) posi-

of

tion. Snap the dogleg on the end

the rod into

the slot in the clip that most closely lines up with

it. Use both hands so as not to bend the actuator lever.

4.

Hook the spring into the slot in the end of the actuator lever. When assembled, the spring hook wires should not wrap around the governor rod.

5.

Move the actuator back and forth through its full

to

movement

make certain there is no sticking

or binding.

6. After installing the top panel, hook the spark

plug cable with the clip inside the panel to keep it from interfering with the governor rod.

lA CAUTION!

screw

Turn

in

it

Forcing a mixture

tight

will

score

lightly

by

hand

the needle

only.

adjusting

and

seat.

2. Start the genset and let it warm up for ten minutes under 1/2 to 3/4 rated load. (On vapor withdrawal type LPG gensets it might be necessary first to adjust the demand regulator and

supply pressure to get the genset to start. See

System-Vapor

LPG

IDLE MIXTURE

ADJUSTING SCREW CAP

ALTITUDE

SCALE

FIGURE 6-11. GASOLINE CARBURETOR

Withdrawal.)

IDLE SPEED

STOP

SCREW

MAIN FUEL

MIXTURE

~ADJUSTING

SCREW CAP

IDLE SPEED

STOP

SCREW

Idle Fuel Mixture

do

not apply

1.

If the carburetor has been overhauled, gently

Adjustment:

to

Spec F and later gensets.

These instructions

turn the idle and main fuel mixture screws in hand until they seat.

For

Gasoline Gensets: Turn the idle mixture

screw out 1 turn and the main fuel mixture screw out 1-3/8 turns so that the engine will

start and run.

by

6-15

FIGURE

6-12.LPG

MAIN FUEL

MIXTURE

ADJUSTING

SCREW

CARBURETOR

3.

Disconnect the load (check for zero amps).

Turn the idle mixture adjusting screw clockwise

until the engine begins to stumble. Then, counting the number of turns, turn the screw counterclockwise until it begins to stumble

in

again. Set the screw halfway closer adjustments, use a CO meter to adjust to 6-8% CO (gasoline) or 4-6% CO (LPG). See

Troubleshooting

4.

Push the adjustment limiter cap on over the mixture screw head such that it will allow equal adjustment retors).

Main Fuel Mixture

tions

do

not apply

1.

Connect rated load.

A.

Load (watts) is the product of volts

amps (A).

(A 1.0 power factor, obtainable with a re-

sistance load bank, is assumed. True

rated output might not be obtained ances are used as part of the load.)

B.

See Section cannot be adjusted to within 1 0 percent of

rated voltage (Table

if

the engine runs roughly.

in

either direction (gasoline carbu-

Adjustment:

to

Spec F and later gensets.

Load (watts)

8.

Generator if output voltage

6-1

between. For

These instruc-

= V x A

).

(V)

if

appli-

and

screw counterclockwise until it begins to stumble again. Set the screw halfway tween. For closer adjustments, use a CO meter to adjust to 6-8% CO (gasoline) or 2-4% CO

(LPG). See

roughly.

3.

Push the adjustment limiter cap on over the

mixture screw head such that the cap pointer

indicates the current altitude (gasoline carburetors).

TABLE

RATED MAXIMUM MINIMUM

OUTPUT NO-LOAD FULL-LOAD

VOLTAGE VOLTAGE VOLTAGE 120V, 1PH

Mechanical

Mechanical governor speed and sensitivity set

points are adjustable.

(Figure 6-13) are accessible through an access

in

cover be

Governor

the governor rod (Figure 6-13) must be checked and adjusted as follows before other adjustments

are attempted:

the panel. The following adjustments must

made

in

Troubleshooting if the engine runs

6-1. VOLTAGE SPECIFICATION

126

Governor

the sequence that they appear.

Rod

Length

(Spec A Only)

The governor and linkage

Adjustment:

The length of

114

in

be-

2.

Turn the main fuel mixture adjusting screw clockwise until the engine begins to stumble.

Then, counting the number of turns, turn the

"\%

GOVERNOR

SPEED ADJUSTING .

SCREW

:::1GURE

6-13.

MECHANICAL

1.

Loosen the lock nut at the ball joint end of the governor rod and unsnap the socket from the

ball.

"\

~'~

""'""

GOVERNOR (SPEC A ONLY)

6-16

...

2. Push the governor rod gently

towa~ds

buretor (full-throttle position). While keeping it there, turn the socket, as necessary, to

or

lengthen

shorten the rod so that the ball and

socket line up.

Iii

CAUTION! Too

can

result

much

in a faulty

pressure

adjustment

on

of

length.

3.

Snap the socket back over the ball.

4.

Tighten the lock nut while holding the socket

square with the axis of the ball. Also, the leg at

the throttle end of the rod must be kept level.

5.

Gently rotate the governor arm and check for binding. If necessary, loosen the locknut and repeat Step 4 until the linkage moves smoothly. Binding can cause erratic governor action.

Note: The performed

Idle Speed

1.

following

in

sequence.

Stop

groups

of

They

adjustments

apply

Adjustment:

to

Spec A only.

If the carburetor has been overhauled, gently

turn the idle and main fuel mixture screws in by

hand until they seat (Figure 6-14).

Turn the idle mixture screw out 1 turn and the

main fuel mixture screw out 1-3/8 turns so that

the engine will start and run.

the car-

the

rod

the

rod

must

be

ure 6-13) to obtain a no-load frequency of 62-63Hz.

2. Turn the idle mixture adjusting screw clockwise until the engine begins to stumble. Then,

counting the number of turns, turn the screw

counterclockwise until it begins to stumble

again. Set the screw halfway in between. For

closer adjustments, use a CO meter to adjust

to 6-8% CO. See

Troubleshooting if the engine

runs roughly.

3.

Push the adjustment limiter cap on over the mixture screw head such that it will allow equal adjustment

in

either direction (gasoline carbu-

retors).

4.

If no-load frequency has changed because of

idle mixture adjustment, repeat Step

5.

Check output voltage. See Section

tor

if

output voltage cannot be adjusted to with-

in 1 0 percent of rated voltage (Table

1.

8.

Genera-

6-1

on

Page 6-16).

IDLE MIXTURE

ADJUSTING SCREW CAP

IDLE SPEED

STOP SCREW

Iii

CAUTION! Forcing a

screw Turn

2.

Start the genset and let it warm up for ten min-

in

tight

it

lightly

will

by

score hand

mixture

the needle

only.

adjusting

utes under 1/2 to 3/4 rated load.

3.

Disconnect the load (checkforzeroamps). Pull the governor rod so that the tang on the throttle lever bears against the idle speed stop screw. Adjust the screw to obtain 54-56 Hz.

Idle Mixture

1.

Disconnect all loads (check for zero amps).

and

Frequency

Adjustments:

Then check no-load frequency. If necessary, turn the governor speed adjusting screw (Fig-

and

seat.

6-17

ALTITUDE

SCALE

MAIN FUEL MIXTURE

ADJUSTING SCREW CAP

FIGURE 6-14. CARBURETOR

Main Fuel Mixture

1.

Connect rated load.

A.

Load (watts) amps (A).

B.

(A 1.0 power factor, obtainable with a resistance load bank, is assumed. True rated output might not be obtained if appliances are used as part of the load.)

C.

See Section cannot be adjusted to within 10 percent of rated voltage (Table

2.

Turn the main fuel mixture adjusting screw clockwise until the engine begins to stumble. Then, counting the number of turns, turn the screw counterclockwise until it begins to stumble again. Set the screw halfway tween. For closer adjustments, use a CO meter

to adjust to 6-8% CO. See

the engine runs roughly.

3.

Push the adjustment limite( cap on over the mixture screw head such that the cap pointer indicates the current altitude (gasoline carburetors).

and

Droop

is

the product of volts (V) and

Load (watts)= V x A

8.

Generator if output voltage

Adjustments:

6-1

on Page 6-16).

Troubleshooting if

in

be-

4.

Disconnect the load and readjust the governor speed adjusting screw to return no-load frequency to 62-63 Hz.

5.

Check and adjust droop.

A.

If droop (from no-load frequency) is more

than 3 Hz for Model BGM or 4 Hz for Model

NHD, turn the governor sensitivity adjusting screw (Figure 6-13) one turn counterclockwise. Disconnect the load and, if necessary, readjust the governor speed adjusting screw to return to 62-63Hz no-load frequency. Check droop again and repeat the adjustments, if necessary.

B.

If droop (from no-load frequency) is less than

2Hz

for Model BGM or

NHM, turn the governor sensitivity adjusting screw (Figure 6-13) one turn clockwise. Disconnect the load and, if necessary, readjust the governor speed adjust-

ing screw to return to 62-63Hz no-load frequency. Check droop again and repeat the adjustments, if necessary.

6.

Check governor response under 1/4, 1/2 and 3/4 rated loads. See is unacceptable.

Troubleshooting if hunting

3Hz

for Model

6-18

.,.,

FUEL SYSTEM

The carburetor mixes air and fuel in the correct pro-

portion for good performance. The governor operates the throttle to maintain a nearly constant engine speed (frequency) as the load varies. Figure 6-15 is representative of most of the fuel system

B.

parts beginning Spec gas) systems do not use an air preheater and have different fuel connections. See Choke Assembly, Fuel Pump and LPG System (Liquid Withdrawal and Vapor Withdrawal) in this section for other details which may be applicable.

LPG (liquified petroleum

or

choke

the adapter. (One of the screws is inside the throat of the adapter.)

Prior

to

Spec D gasoline and Spec F LPG, the choke linkage choke as the moved. See Figure 6-16.

5.

Beginning Spec D gasoline, disconnect the leads at Relay K4 bracket from the

must

be disengaged

air

cleaner adapter

or

remove the relay and

air

cleaner adapter.

from

is

being re-

the

Reassembly: Reassembly is the reverse of disas-

sembly. Use a new gasket between the adapter and the carburetor.

See GOVERNOR AND CARBURETOR ADJUSTMENTS

IAwARNINGI

and

injury gasoline burning

ventilation with

sparks,

switches

in

this section for carburetor adjustments.

Gasoline

explosive

or

death. Do

vapors

equipment

pilot

and

flames,

other

and

LPG are flammable

can cause severe

not

smoke

or

are

or

such

equipment. Keep flames,

near

are

if

fuel

in

you

an

tanks

area

electrical

sources

of

ignition

personal

smell

or

sharing

arcs

gas

fuel-

and well

or

away.

IAwARNINGI

and

can cause asphyxiation. NFPA

1.6 requires trained

in

proper

LPG

all

is

flammable

persons

handling

and

handling and

operating

explosive

58,

Section

LPG

to

proce-

be

dures.

Air

Cleaner

Assembly

Disassembly:

1.

Remove the crankcase breather hose and air preheater hose (gasoline gensets only) from

the air cleaner housing.

2. Remove the air cleaner housing center capscrew and lift off the housing and air filter.

3.

Prior to Spec D gasoline and Spec F LPG, remove the choke cover retaining nut and cover and disconnect the leads connected at the terminals.

4.

Remove the three capscrews that secure the air cleaner adapter to the carburetor and lift off

lA

CAUTION! Make

to

mount screw choke

Take care

the

inside

shaft

also

Carburetor

adapter

the

if

it

is

not

And

sure

you

throat

too

long

to

cross

Intake

use

the

right

on

the carburetor. The

will

interfere with the

or

tightened

thread

Manifold

too

it.

Assembly

screws

tight.

Disassembly:

1. Remove the top panel (see COOLING SYSTEM in this section).

2.

Remove the air cleaner assembly.

3.

Disconnect the fuel line and governor rod from

the carburetor (see GOVERNOR AND CAR-

BURETOR ADJUSTMENTS

4.

Remove the intake manifold capscrews, the carburetor air preheater (gasoline gensets only) and the carburetor and intake manifold as an assembly.

Prior

to

Spec D gasoline and Spec F LPG, disengage the choke pull tor. See Figure 6-17.

5.

Remove the two intake manifold gaskets and cover the intake ports to prevent loose parts and dirt from entering the engine.

6.

Unbolt the carburetor from the intake manifold.

off

linkage

in

this section).

from

the carbure-

Reassembly: Reassembly is the reverse of disas-

sembly. Use new gaskets between the intake manifold and the engine and between the intake man-

ifold and the carburetor. Do not use sealer gaskets. Tighten all fasteners according to

4.

Torque Specifications.

on

the

Section

CRANKCASE

BREATHER

HOSE AND CLIP

AIR PREHEATER AND HOSE

(gasoline gensets only)

(Slip the

preheater hose and insert it into the

0-RING

0-ring

over the end of the

collar)

RELAY

K4

BOLTS TO

REAR

OF

AIR

CLEANER ADAPTER

INTAKE

MANIFOLD

ADAPTOR TO

CARBURETOR

GASKET

~GASOLINE

\ CARBURETOR/CHOKE

~

AIR CLEANER ADAPTOR

~~

----;

AIR CLEANER HOUSING

AIR

FILTER

ELEMENT

~

\

ASSEMBLY

MANIFOLD

GASKETS

MANIFOLD

GASKET

THROTTLE

LEVER

FIGURE 6-15. TYPICAL FUEL SYSTEM (BEGINNING SPEC D GASOLINE)

-----r

6-20

_

_)

\

CRANKCASE

;EATHER

~,

I

TUBE

~

""

AIR

PREHEATER

(gasoline only)

AIR ALTER

HOSE

CARBURETOR

""-~.....,.

CHOKE COVER

FIGURE 6-16. AIR INTAKE ASSEMBLY (PRIOR

AIR

PREHEATER

•

"'\,

TO

AIR

CLEANER

ADAPTER

SPEC D GASOLINE AND SPEC F LPG)

l

~

)

1/

CARBURETOR

INTAKE

MANIFOLD

GOVERNOR

ROD

FIGURE 6-17. CARBURETOR AND INTAKE

""'0-_J

MANIFOlD

(PRIOR TO SPEC D GASOLINE AND SPEC F LPG)

'

J

__

~···.{

FUEL

FILTER

v

Carburetor Replacement

(Beginning Spec

Beginning Spec

should not be overhauled. Instead, a malfunction-

ing carburetor should be replaced. Before replacing

a carburetor, however, make certain 1) that all other

necessary engine and generator adjustments and repairs have been performed and 2) that the carburetor is actually malfunctioning, by carefully following the troubleshooting procedures

shooting.

F)

F,

the gasoline or LPG carburetor

in

Trouble-

LPG carburetors are usually

all

lems. Make certain problem have been eliminated before replacing LPG carburetor.

IAWARNINGI Unauthorized modifications

placement control emissions are

of

fuel, exhaust,

system

prohibited

other possible causes

components

not

by

air

that

law

the cause

intake

or

affect engine

in

the State

of

prob-

of

or

speed

California.

the

an

re-

of

6-22

Gasoline Carburetor Overhaul (Prior

See Figure 6-18. Carburetor problems not corrected by mixture or float adjustments are often

caused by gummed-up fuel passages

nal parts. The most effective remedy is to replace overhaul the carburetor. Overhauling a carburetor consists of complete disassembly, thorough clean-

ing and replacement of worn parts. Repair kits are available for gasoline carburetors that include new

gaskets and float assembly parts.

to

Spec

F)

or

worn inter-

or

Disassembly: Carefully note how the carburetor

parts fit together as the carburetor is being

disassembled so that it will be easier to reassemble.

Read and understand these instructions before

starting.

1.

Remove the air cleaner adapter and the automatic choke assembly (gasoline carburetors).

2.

Remove the main and idle mixture screw assemblies.

4. Replace the fuel mixture screws if they are scored (Figure 6-19).

5.

Replace the carburetor the throttle sticks after cleaning. It is usually not necessary to disassemble the throttle

~

CHOKE

SHAFT

if

-,~---

either the choke

or

choke.

CHOKE

PLATE

THROTTLE

SHAFT

or

3.

Separate the lower section of the carburetor (float bowl) from the body of the carburetor.

4.

Carefully note the position of the float assembly parts, then remove the hinge pin, float and needle valve.

Cleaning

1 . Soak all metal components not replaced by the

I:AWARNINGI

2.

3.

and

Inspection: .

in

repair kit rubber or plastic parts. Follow the cleaner manufacturer's recommendations.

are flammable severe as

recommended

Clean all carbon from the carburetor bore, especially where the throttle and choke plates seat.

ports.

Blow out all passages with compressed air. Do

not use wire might increase the size of critical passages.

carburetor cleaner. Do not soak any

Most

burns

Be

careful not to plug the idle or main fuel

or

parts

and

corrosive

and

by

other objects for cleaning that

cleaning

and

can cause

solvents

inflammation. Use

the manufacturer.

only

FUEL

INLET

NEEDLE

VALVE

MAIN FUEL

MIXTURE

ADJUSTING

ASSEMBLY

FIGURE 6-18. GASOLINE CARBURETOR

FIGURE 6-19. TYPICAL FUEL MIXTURE SCREW

_______.,!

.:+Jl

JEP

CHECK FOR

SCORING HERE

FLOAT

BOWL

6-23

Reassembly:

1.

See Figure 6-20. Turn the carburetor upside

down and install the new needle valve, float,

float hinge pin and fuel bowl gasket in the repair kit. Make sure the wire clip properly engages the groove around the end of the needle valve and loops around the metal tang (The clip pulls down on the needle valve when the float level drops, breaking the needle loose

if

it is stuck.) Check to see that the float moves

freely without binding.

2. See Figure 6-21. Check the float level as shown while the carburetor is still upside down. Measure the height above the bowl gasket flange on the side opposite the hinge. Make sure the full weight of the float is resting on the needle valve. Remove the float and bend the metal tang

to

adjust the height.

of

the float.

lA CAUTION! Remove the float before bend-

ing

the tang

nose

of

3.

Install the float bowl and the main mixture

screw assembly.

so

as

not

to

the needle valve.

damage the

soft

WIRE CLIP

FLOAT

HINGE PIN

NEEDLE VALVE

-·~---~

FLOAT HINGE PIN

RETAINING SCREW

FIGURE 6-20. FLOAT INSTALLATION (GASOLINE)

0.59-0.63 INCH (15-16

mm)

BEND METAL TANG TO

ADJUST FLOAT HEIGHT

4. Install the idle and main fuel mixture screws. Turn them lightly by hand until they seat. Then tum

the idle mixture screw out 1 turn and the main fuel mixture screw out 1-3/8 turns so that the engine will start and run.

5. If it is necessary choke, secure the plate screws such that they will not loosen.

lA CAUTION! Loose

screws

can

get

to

reassemble the throttle

throttle

drawn

or

into

the engine

choke

or

plate

and

cause serious engine damage.

THE FULL WEIGHT

REST ON THE NEEDLE VALVE WHILE

MEASURING FLOAT HEIGHT

FIGURE 6-21. FLOAT LEVEL (GASOLINE)

OF

THE FLOAT MUST

6-24

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

Choke (Prior

Assembly

to

Spec D Gasoline and Spec F LPG*)

Choke Settings: Table 6-2 lists choke settings for

various ambient temperatures. Stop the set and let it cool before adjusting the choke.

1.

Remove the plastic choke cover (see Figure 6-22) and loosen the heating element cover screws.

2. Rotate the heating element until the choke plate is halfway open.

3.

Slowly rotate the cover counter clockwise while

tapping the carburetor choke lever to make it

bounce. Continue until the lever no longer bounces. This is the fully-closed (reference) position.

4.

Refer to Table 6-2 to determine the number of degrees the element cover must be rotated clockwise from the reference position. The marks on the choke housing are spaced at 5° intervals.

5.

Rotate the element cover as specified, then tighten the cover mounting screws.

6. Move the choke lever to test its operation. The lever should return to the free position when released from the open position, without sticking

or binding.

7. Install the plastic choke cover and tighten the

center mounting unit.

* Each

TABLE

Ambient

Temperature

. 40°F(4°C)

45°F(7°C) 50°F(10°C) 60°F(16°C) 65°F(18°C) 70°F(21°C) 24°CW 75°F(24°C) 80°F(32°C) 85°F(29°C) 90°F(32°C) 39°CW 95°F(35°C)

1 00°F(38°C)

mark

6-2.

CHOKE

Air

on choke housing equals

SETTINGS

Rotation from

Reference Mark*

oo

4°CW

aocw

16°CW 20°CW

27°CW 32°CW 35°CW

43°CW 47°CW

so

HOUSING

FIGURE 6-22.

* Beginning Spec

ELEMENT

COVER

CHOKE

F,

LPG models do not incorporate a choke.

ASSEMBLY

(SPEC A

BI-METAL

SPIRAL STRIP

I

GASOLINE

6-25

AND

UP

TO

/

SPEC E

PLASTIC

COVER

LPG)

Choke Replacement: If the choke does not open,

remove the protective plastic cover and check the

The

heating element. heat up after a few minutes ment cover remains cool, start the set, then use an AC voltmeter roughly

to

20

VAC is not present, check for opens

shorts in the control wiring.

If voltage is present, stop the set and remove the heating element cover. Inspect the heating element and replace it if burned the bi-metal coil and replace it if it is damaged or

in

binding

the housing.

When installing a new bi-metal strip, maintain the original direction outer tab must point in a clockwise direction. Make sure that the coil sets squarely in the housing, and that the inner end choke shaft. must engage

The

the

heating element cover should

of

operation. If the ele-

check the terminals on the cover. If

or

out

or

broken. Also inspect

ofthe

spiral {see Figure 6-23). The

of

the coil engages the slot in the

slotted tang on the element cover

bi-metal strip.

2. Disconnect the diaphragm hose from the intake manifold. Apply 4-18 inch ( 13.5-60.8 kPa)

Hg vacuum to the diaphragm.

3.

Apply light finger pressure against the choke

to

lever

take up all free play

in

the pull off linkage

(see Figure 6-24). Check

4.

and correct the alignment

of

the diaphragm stem, pulloff linkage, and slot in the choke lever, viewing them from above.

5.

Measure the distance between the choke plate

at

and the bottom of the carburetor

the point in-

dicated in Figure 6-24. There should be

0.39-0.43 inch (9.9-1 0.9 mm) clearance here;

if necessary, bend the diaphragm mounting

to

bracket

6.

Move the choke lever back and forth

that it does not bind

reach this clearance.

or

stick.

to

verify

7. Remove the vacuum supply from the diaphragm. Install the filter assembly on the carburetor.

OUTER TAB

FIGURE 6-23. BI-METAL COIL

Choke

Pulloff

Diaphragm

Adjustment:

The

choke pulloff diaphragm partially opens the choke

This

plate after engine startup.

inhibits flooding, and promotes smooth engine operation as the set warms up.

1. Remove the air cleaner assembly as described in Air Cleaner Assembly in this section, to ac-

cess the choke plate.

CHOKE

LEVER

FIGURE 6-24. CHOKE PULLOFF DIAPHRAGM

PULL OFF

LINKAGE

DIAPHRAGM

MOUNTING

BRACKET

6-26

Choke Assembly (Beginning Spec D Gasoline)

See Figure 6-25. The choke is operated automatically by a 12 VDC heater/bi-metal assembly and a

of

vacuum break, both side of the carburetor by a bracket. Reassemble the choke components as shown.

The choke bi-metal/heater assembly is adjusted at the factory. If the factory settings have been disturbed, loosen the three bezel ring screws at the

base of the assembly and rotate the body counter-

which are mounted on the

clockwise for a richer setting and clockwise for a leaner setting and retighten the screws.

The choke plate opening should be checked with a gauge each time the vacuum break is remounted.

as

Check and readjust the opening

1.

Apply a vacuum of

at

least 4 inches

follows:

(1

00 mm)

mercury to fully pull in the vacuum break arm.

2.

Insert a 0.337 inch (8.6 mm) drill rod between

the choke plate and the carburetor throat.

3.

Bend the link at the point shown, if necessary, until the lip of the choke plate just touches the drill rod. Use two pliers to bend the link.

JA

CAUTIONJ

KINKS IN THIS VACUUM

HOSE

CAN CAUSE HARD

AND

STARTING

CARBURETOR

IDLING

IF NECESSARY, BEND THIS LINK AT

WHEN

THIS POINT

OPENING

ADJUSTING

OF

THE CHOKE PLATE

THE

~/

CHOKE

PLATE

GAUGE THE OPENING

BI-METAL/HEATER

ASSEMBLY

FIGURE 6-25. CHOKE ASSEMBLY (BEGINNING SPEC D GASOLINE)

IN THE CARBURETOR THROAT WITH A

0.337 INCH {8.6

OF

THE CHOKE PLATE

mm) DRILL ROD AS SHOWN

6-27

Fuel Pump (Gasoline Gensets}

If a problem BLESHOOTING pressure as follows:

1.

Disconnect the fuel line at the outlet pump and connect a pressure gauge at the pump outlet. A gauge calibrated for 0-15 psi

(0-1

the fuel line. This is a static pressure test.

2. Push the Start/Stop switch to START and hold it there for several seconds until the fuel pressure stabilizes. Fuel pressure should stabilize between 3.5 and 6 psi (24 and

3. Repeat the test with the vehicle engine running.

A

fuel acceptable. high when the vehicle engine is not running, check to see that the proper Onan supplied pump is being used. If it is high when the vehicle engine is running,

in

fuel delivery is indicated (see TROU-

in

this section), test fuel pump

of

the fuel

00 kPa) is recommended. Do not tee into

41

kPa).

pressure

greater

Find out why the pressure is high. If it is

than 6 psi

(41

kPa)

is

not

a separate fuel pickup tube equivalent means, will be required.

If the fuel pressure is less than 3.5 psi (24 kPa),

check for fuel restrictions in the system. If the pump is defective, replace it with the appropriate Onan pump. The pump is not serviceable.

lA

CAUTION! Tampering with the seal

ter

of

the

pump

mounting

can cause the

bracket

dry

the electrical components to leak* leading

pump

IAWARNINGl

fuel the flooding

failure. The

Do

not

pump

for

the standard

genset. Other

because

pump

substitute an automotive

pumps

of

the velop. Carburetor flooding can cause formance sible Fuel exceed 6

and

fire

and

pressure

psi

(41

engine damage

severe

at

personal

the carburetor

kPa)

under

in

the fuel tank, or

at

the cen-

on

gas

is

not

pump

the side

which

serviceable.

removed from

of

surrounds

can cause carburetor

high

pressures

they

poor

and

lead

to

pos-

injury

fitting

any

or

death.

must

operating con-

the

to

de-

per-

not

dition.

6-28

LPG

System-Liquid

See Figure 6-26. For liquid withdrawal systems the LPG container(s) must be equipped to withdraw LPG as a liquid. See the Installation Manual for important recommendations regarding the installation of a LPG liquid withdrawal type of fuel supply system.

IAWARNINGI LPG

and

can cause asphyxiation. NFPA 58, Section

all

1.6 requires trained dures.

It is important to understand that the fuel filter, solenoid shutoff valve, vaporizer and demand regulator handle LPG liquid at the same pressure as in the

in

proper

persons

handling

Withdrawal

is

flammable

and

handling

and

operating

explosive

LPG

to

proce-

be

LPG container. Depending on ambient temperature, LPG container pressure can exceed 200 psi (1379 kPa). Therefore, discharge LPG liquid-containing components can result in the escape of large volumes of flammable and explosive gas.

Purging

LPG system be purged before disconnecting fuel

system components.

IAWARNINGI Large volumes

leased

withdrawal type instructions for disconnecting

the LPG System: It is imperative that the

in

the

proper

process in

Section 5. Preparing

procedures

LPG

of

disconnecting a liquid-

LPG

supply

and

fuel

lines.

or

leakage from

of

LPG

can

system. See the

to

Service

precautions

be

re-

when

LPG

REGULATOR

\

LPG

VAPORIZATION

TUBE

EXHAUST

MANIFOLD

REGULATOR

MOUNTING

BRACKET

TOPVIEW

FLEXIBLE

HIGH

PRESSURE

LPG HOSE

SIDE VIEW

I

LPG FILTER

(Note Direction

of Arrows)

FIGURE 6-26. LPG SYSTEM COMPONENTS FOR LIQUID WITHDRAWAL

6-29

Demand Regulator: See Figure 6-27. The two-

stage demand regulator delivers vaporized LPG to the carburetor.

por (and liquid) at LPG container pressure and reduces it to approximately 1.5 psi secondary stage delivers LPG vapor at the rate de-

manded by the carburetor. The regulator should require little attention if the

genset is operated regularly. Most problems are

due to:

• Hardened Diaphragms, Gaskets and

Seats: Diaphragms, gaskets and valve seats

tend to shrink and harden when a genset is stored for long periods of time and may need to be replaced.

.,

Impurities and Dissolved Oils

Impurities can embed on valve seats causing them to leak and oils can clog regulator pas-

The

primary stage receives LPG va-

(1

0.3 kPa). The

in

Liquid LPG:

Valve

sages, resulting and poor load acceptance.

Primary Pressure

1.

Connect a pressure gauge to the primary pres-

sure test port and a source of compressed air (at least 80 psi [550 kPa]) to the inlet port.

2.

The gauge should indicate approximately 1.5 psi

(1

0.3 kPa) and hold steady when the test

pressure valve is opened. The pressure should

not drop off when the test pressure valve is closed.

3.

Disassemble and clean and retest the regula-

tor if it cannot hold the proper pressure. Re-

place it if it still does not function properly.

14wARNINGI Parts cleaning

flammable

burns

manufacturer's instructions.

and

in

hard starting, erratic idling

Test:

and

corrosive

inflammation.

solvents

and

can cause

Follow

are

the

SECONDARY fl

DIAPHRAG~~

SECONDARY

~~E

COMPONENTS

INLET PORT

(Beginning Spec

~

F)

~

INLET PORT

(Prior to

1- Beginning Spec

plunger serves a!so as the primary valve.

The separate part labeled "PRIMARY

VALVE" is no longer provided.

2- Make sure the smailest ho!e in the gas-

ket

Spec

F)

F,

the primary va!ve

lines up with the small hole for the test

Flip the gasket over

if

necessary.

FIGURE 6-27. DEMAND REGULATOR

~'

i

'

I

'

I

'

'l

I~

cJ:?

-----

PRIMARY

PRIMARY GASKET2

VALVE

1

I

.

"'

'

I

'

I

I I

~·

I

'

i~

r .

'

..___________

~

PRIMARY

PRESSURE

TEST

PORT

PLUG

PRIMARY VALVE

PLUNGER AND

SPR!NG

1

ta

I

1

ASSEMBlY

PRIMARY

DIAPHRAGM

6-30.

Fuel Filter: See Figure 6-28. The fuel filter removes

rust and scale and other solid particles from the LPG liquid to keep them from embedding in the valve seats of the shutoff valve and pressure regulator and causing them to leak. A magnet traps iron and rust particles and a filter element traps nonmagnetic particles.

Disassembling

1.

Purge the LPG system as instructed in Section

5.

Preparing to Service.

2.

Remove the four capscrews and lock washers

that hold the filter bowl to the filter body.

3.

Separate the filter bowl from the filter body and

discard the

4.

Remove the nut and washer from the center stud and pull out the filter element.

5.

Wash the filter element particles it has collected. Blow it dry with low pressure (30 psi Replace the filter element if damaged.

IAWARNINGI

flammable burns

and

Cleaning the Fuel Filter:

0-ring

seal.

I 207 kPa) compressed air.

Parts cleaning

and

corrosive

and

inflammation.

in

solvent to remove the

solvents

and

can cause

Follow

are the

manufacturer's instructions.

6.

Wipe the magnet clean of the particles it has collected.

7.

Install a clean filter element using two new gaskets and securely tighten the center stud nut.

Fuel Vaporizer: The fuel vaporizer consists of tub-

ing clamped to the exhaust manifold. See EXHAUST SYSTEM in this section for removal.

Fuel

Shutoff

noid by disconnecting its long lead and jumpering it directly to the battery positive (+)terminal on the

genset. Replace the solenoid if it does not "click''

open when it is powered.

GASKET

0-RING

SEAL

Solenoid Valve: Test the fuel sole-

FILTER

BODY

ce

@J

~

MAGNET

8.

Place a new

groove.

9.

Align the reference mark on the filter bowl with the reference mark on the filter body and torque the capscrews to 651bs-in (7.2 N-m). Check for

and fix leaks at the filter when connections have been made to the fuel supply system. fuel

filter

sure.

0-ring

operates

in the filter bowl sealing

at

fuel

supply

tank

The

pres-

FILTER

BOWL

FIGURE 6-28. LPG FUEL FILTER

(LIQUID WITHDRAWAL SYSTEM)

6-31

LPG

System-Vapor

Withdrawal

mand regulator. These are available as a kit for mounting near the genset. See Figure 6-29.

See the Installation Manual for important recom-

mendations regarding the installation of an LPG vapor withdrawal type of fuel supply system. Gensets equipped for vapor withdrawal of LPG must be equipped with a fuel shutoff solenoid valve and de-

SOLENOID PIGTAIL

CONNECTIONS AT THE GENSET

GAS SUPPLY HOSE TO

THE CARBURETOR INLET

IAWARNINGI

and

can cause asphyxiation.

1.6

requires

LPG

is

flammable

all

persons handling LPG to be

trained in proper handling

dures.

MOUNTING

BRACKET

and

explosive

NFPA

and

FUEL SHUTOFF

SOLENOID VALVE

58,

operating proce-

Section

VENT/PRESSURE-BALANCE HOSE

(Must extend outside the genset compartment to

prevent accumuiation of LPG

event the diaphragm leaks and to prevent erratic fuel

delivery because of pressure fluctuations cause by

the cooling air flow through the compartment)

FIGURE 6-29. LPG SYSTEM

in

compartmePt

in

the

(The regulator must be mounted such that

the diaphragm is in a vertical plane, as

shown, to maintain calibrated gas pressure.)

COMPOf~Et'liTS

FOR VAPOR WITHDRAWAL

6-32

DEMAND REGULATOR

LPG

Supply

be maintained column (WC) under all conditions. Adjust the supply pressure as follows:

1.

Close the gas shutoff valve(s) at the LPG container(s).

2.

Remove the 1/8 inch pipe plug from the regulator test port (Figure 6-30) and connect a manometer calibrated a scale range of at least 14 inches (350 mm).

3.

Open the LPG container shutoff valve and try starting the genset.

4.

While the genset is running, check the manometer and adjust the LPG supply pressure regulator to obtain there is a secondary pressure regulator supply line, adjust the secondary regulator instead of the primary regulator at the LPG container.)

5.

If the genset will not start, jumper the fuel sole-

noid to the battery cable connections on the genset so that it stays open (the regulator will keep gas from flowing)and then check and adjust the LPG supply pressure.

6.

If the genset is operable, check LPG supply

pressure under full load. If it drops below the

minimum required pressure, either the LPG container is too small to provide the rate of va-

porization necessary or it is less than half full or the supply line is too restrictive.

7.

Disconnect any jumpers which may have been

used to energize the fuel solenoid and thread

in

and tighten the pressure test port plug unless

tests are going to be continued.

Pressure: LPG supply pressure must

at

9-13 inches (229-330 mm) water

in

inches

11

inches (279 mm) WC. (If

or

mm WC having

in

the

we.

If

this

sure

Lock-Off

is

a bench test

the diaphragm

Demand Regulator

Lock-off pressure is determined as follows by pressurizing the back (vent) side of the regulator diaphragm to simulate carburetor venturi vacuum:

1.

Continue with the test setup for adjusting LPG supply pressure shown in Figure 6-30. If the

regulator is being tested on the bench, connect it

to

a source of air pressure regulated to

ches (280 mm)

lA CAUTION!

ulator, make

Pressure Test:

11

in-

of

the reg-

is

in

a ver-

tical plane (see Figure 6-29), otherwise the

of

weight

neous readings

2.

''T''

in nected to the regulator vent fitting (3/8 inch I.

D.). Use one hose to provide the test pressure and the other to measure pressure by connecting it to an inclined manometer calibrated with

0.01

ing a range of at least 1 inch (25 mm) WC.

3.

Disconnect the hose to the carburetor and attach a soap bubble to the regulator outlet hose fitting. While reading the pressure indicated by the inclined manometer and watching the soap bubble, blow lightly into the hose being used to pressurize the regulator. Regulator lock-off

pressure is the minimum pressure that will cause gas to flow through the regulator, as indicated by the expanding soap bubble. (At first the soap bubble may expand due to diaphragm

movement but will stop expanding

is not flowing through the regulator.)

For

Gensets

demand regulator if the lock-off pressure does

not fall between 0.15 and 0.25 inch

and 6.4 mm WC).

the diaphragm

of

lock-off

two hoses to the end of the hose con-

inch or 0.2 mm

Beginning

will

cause erro-

pressure.

we

divisions and hav-

if gas

or

Spec F: Repiace the

we

air

(3.8

Fuel

Shutoff

lenoid of gas pressure on the manometer scale vious test) when it is jumpered across the the battery cable connections at the genset.

if

Solenoid Valve: Replace the fuel so-

it fails to open (as indicated by the absence

in

the pre-

6-33

liiwARNINGI

replacement

speed

control fect engine in

the State

Unauthorized

of

fuel, exhaust,

modifications

system components

emissions

of

California.

are

prohibited

air

intake

that

by

or or

af-

law

For

Gensets

pressure as follows:

• If the lock-off pressure inches (6.4 mm)

screw and back out the adjusting screw

(counterclockwise) until the lock-off pressure falls between 0.15 and 0.25 inch (3.8 and 6.4 mm WC). Set the locking screw and test lock-off pressure again. Repeat the procedure if necessary.

• If the lock-off pressure inch (3.8 mm) screw and turn (clockwise) until the lock-off pressure falls between 0.15 and 0.25 inch

6.4 mm WC). Set the locking screw and

Prior

to

Spec F: Adjust lock-off

is

greater than 0.25

we,

remove the locking

is

less than 0.15

we,

remove the locking

in

the adjusting screw

we

(3.8 and

test lock-off pressure again. Repeat the procedure if necessary.

• Replace the demand regulator if it continues to leak after lock-off pressure adjust-

ments have been attempted.

4.

If the genset is mounted

make sure the vent/pressure-balance hose

routed properly to the outside.

5.

Reconnect the hose to the carburetor, discon-

nect any jumpers which may have been used to energize the fuel solenoid and thread tighten the pressure test port plug.

6.

For gensets prior to Spec

as instructed under GOVERNOR AND CAR-

BURETOR ADJUSTMENTS

in

a compartment,

F,

adjust fuel mixture

in

this section.

in

is

and

LOCK-OFF ADJUSTING SCREW

(Beginning Spec

not accessible for adjustments)

LPG iNLET

(11

inch

HOSE

F,

we

pressure)

'T'

TESTING

FOR

this screw is

------

~

LPG OUTLET TO

CARBURETOR

(Place soap bubble on

end of hose fitting)

----t:.\-..;';j

PRESSURE

/

/'

- /

\t?

TEST

MANOMETER

(Connected to LPG supply

pressure test port)

VENT/PRESSURE-BALANCE HOSE

(See Figure 6-29 for a view of the vent hose

fitting when it

is

located

on

the other side.)

..)

FIGURE 6-30. LPG

SUPPlY

PRESSURE AND REGULATOR LOCK-OFF PRESSURE

6-34

ELECTRIC STARTER

Starter Removal and Replacement

Starter Disassembly

To

remove the starter for service or replacement:

1.

Disconnect the negative (-) cable from the

starting battery.

2.

Disconnect the cable

3.

Remove the two starter mounting bolts and remove the starter.

Replacement is the reverse of removal. Torque the mounting bolts to specifications.

METAL

SPRING/

RETAINER &

WASHER

at

the motor terminal.

CLUTCH & SPLINE

ROLL ASSEMBLY

~

I --------i

Motor Disassembly: See Figure 6-31. Remove

the starter from the genset. The drive housing, mo-

tor frame and end bell are separable after the motor

through bolts have been removed. Before loosen-

ing the through bolts, however, scratch register

lines on the drive housing, motor frame and end bell so that these parts can be easily reassembled the same way relative to each other. While removing the end bell, be prepared to catch the brush springs, which tend to spring loose.

SPRING

WASHER

.,

RETURN

SPRING

~----

MAGNETIC

FIGURE 6-31. STARTER ASSEMBLY

HOUSING

-----

BRUSH

END CAP

--

-----

THROUGH

BOLT

15-35

Removing the

Roll

Pin: Remove the return spring,

gear and clutch assembly if necessary by driving out the roll pin. Use a 1/8 to 5/32 inch nail set (Figure

new

6-32). Always use a

roll pin when reassembling

the drive assembly.

5/32-1/8

inch

NAIL

SET

SUPPORT PLASTIC RETAINER WITH A VISE OR OTHER

SOLID SURFACE. USE CARE NOT TO HAVE SPRING

RETURN "LEG" BETWEEN THE PLASTIC RETAINER

AND SUPPORT WHEN DRIVING OUT ROLL PIN

ROLL

Testing Armature

for

Shorts: Use a growler (Fig-

ure 6-34) to locate shorts in the armature. Place the armature

in

the growler and hold a thin steel blade

(hacksaw blade) parallel to the core and just above

the armature, while slowly rotating the armature in the growler. to

vibrate and be attracted

shorted armature with a

A shorted armature will cause the blade

to

the

core. Replace a

new

one.

HACKSA~

FIGURE 6-32. REMOVING

ROLL

Testing and Inspecting the Starter

Testing

meter er lead tions (Figure 6-33). cates a grounded armature. Replace a grounded

armature with a

Armature

for

Grounds: Touch one ohm-

lead to a commutator bar, then touch the oth-

to

the armature shaft and the core lamina-

A

low

resistance reading indi-

new

one.

COMMUTATOR

BARS

FIGURE 6-33. TESTING ARMATURE FOR

GROUNDS

FIGURE 6-34. TESTING ARMATURE FOR SHORTS

Testing Armature

for

Opens: Touch one ohmme-

ter lead to a commutator bar, then touch the other

lead to each

of

the other commutator bars in turn. A

high resistance indicates an open circuit between

the commutator bars and armature windings. Re-

new

place an open armature with a

Brush

and replace them

(11

Inspection: Measure brushes (Figure 6-35)

if

worn to less than 0.425 inch

mm).

0.425 INCH WEAR LIMIT

(11

mm)

FIGURE 6-35. BRUSH INSPECTION

one.

N

0.570 INCH

(14.5 mm)

+

6-36

Starter Assembly

Use this procedure to return the electric starter assembly to service.

1.

Wipe dirt and oil from starter components using

or

a clean cloth; pressure compressed air.

lA CAUTION!

starter. Do

ing

fluid. Use a

gine

oil

to remove

getting

2.

Mount the brush springs on tabs as shown

Figure 6-37. Using a small screwdriver, turn the spring counterclockwise to torque it, so the contact loop is inside the brush holder. The spring should be pushed down to the mounting tab shoulder.

3.

Push the negative brush terminals over the

through-bolt holes on the brush endcap.

oil

blow off dirt with filtered low-

Oil

on

armature

not

immerse bearings

on

brushes

brush

dipped

dirt

from bearings.

or

will

in

commutator.

damage

in

clean-

clean en-

Avoid

in

7.

Place a washer on the commutator end of the shaft, and put the armature into the brush endcap. Push the four brushes toward the commutator, making sure that the springs are correctly positioned on the brushes. Recheck to be certain that the spring is pushed all the way down on the mounting tab.

8.

Make sure that all brush wires are clear of the commutator, and that uninsulated portions of insulated wires do not touch the inside of the

or

housing,

9.

Place the magnetic housing over the armature. Hold down the armature and the end cap using a nut driver pressed over the end of the shaft.

1

0.

Place a spring washer and a flat washer on the shaft, as shown in Figure 6-31.

adjacent brush boxes.

4.

Insert a positive brush stud into the hole, and

torque to 25-30 in-lb (2.83-3.39 N-m}.

5.

Insert a small screwdriver into the brush spring

contact loop to bend the spring back so that

each brush can be inserted into the holder. Be

sure that all brush wires are facing up.

6.

If the brushes are at least 0.430 inch

long, rest the brush springs against the sides of

the brushes to keep them clear during arma-

ture installation. See Figure 6-36.

(1

0.9 mm}

FIGURE 6-36. RESTING BRUSH SPRING ON SIDE

OF BRUSH

6-37

11.

Place the mounting bracket on the motor, facing the exposed end of the sleeve bearing and through-bolt lead-ins toward the inside of the motor. The flat near one mounting hole should line up with the positive stud on the end cap, so the through-bolts can line up.

12. Insert the through-bolts, and torque to 35-45 lbs-in (3.96-5.09 N-m).

13. Wipe dust from the helix and gear, and apply a

light coat

of

GE

Versilube 322-L

to

the outside diameter of the helix, the inside diameter of the gear and the unchamfered end of the gear.

Place the clutch and helix assemblies on the

motor shaft, with flats engaged in the clutch

hole.

14. If the return spring is unassembled,

do

the fol-

lowing:

A. Place a 1-1/16 inch O.D. washer over the

end

of

the shaft.

B.

With the chamfered side of the shaft hole facing up, place a plastic retainer on the

shaft and line up the hole with a hole in the shaft.

C.

Support the plastic retainer with a vise other solid surface. Using a 5/32

or

1/8

inch nail set and hammer, drive in a new

roll pin. The pin should be driven about 1/10th of an inch {2.5 mm) from the edge

of the plastic retainer,

or

in such a way that

it is evenly spaced from each side.

D.

Place the spring cover over the top of the plastic retainer, then place the return

spring on top of the retainer.

E.

With a washer placed over the point of the

plastic retainer, push the metal retainer into the hole of the plastic retainer

as

far as

it will go.

15. Mount the starter on the generator stator housing using capscrews, lockwashers and nuts.

Tighten the mounting screws to 30-33 lbs-ft

(41-45 N-m).

16. Reconnect the starter cable and battery.

POSiTIVE

BRUSH

STUD

BRUSH

/

TO

TORQUE

5-10 LBS-iN

(.57-1.13 N-M)

NEGATIVE TERMINAL

TORQUE

25-30 LBS-IN

(2.83-3.39 N-M)

TO

I

NEGATIVE

BRUSH

TERMINAL

FiGURE 6-37. BRUSH END CAP

IMPORTANT!

BE

ROUTED

SHUNT

WITH

COMMUTATOR

IMPORTANT! SPRING

MUST

BE

ASSEMBLED

i'v10UNTING

SHOWN.

AS

THIS

INSULATED SHUNT MUST

THROUGH UNINSULATED

SHOWN

TAB

AS

TO

PREVENT

IN

FINAL

ON

~..J...,,...,-..,

CONTACT

ASSEMBLY.

Section 7. Control System

INTRODUCTION

The control system governs the following functions:

•Starting

• Monitoring for fault conditions

•Instrumentation

•Stopping

• Engine speed governing (electronic governor sets only)

SPARK PLUGS (TOP ACCESS

TO FRONT AND REAR PLUG)

AC

OUTPUT LEADS

60

OIL

DRAIN KNOB

(3/8 INCH SQUARE

DRIVE)

POSITIVE (

BATTERY

CONNECTION

+)

''4--:~:::::..__NEGATIVE

CABLE CONNECTION

(1

OF

OPTIONAL

0.501NCH FLEXIBLE

CONDUIT

CONNECTION

M-1801s

FIGURE 7-1. BGMINHM GENERATOR SET (MECHANICAL-GOVERNOR VERSION)

INCHES (1.5 M)

LONG

(-)BATTERY

4): LOCATION

CONTROl

DESCRIPTION

(Mechanical governor gensets)

panel. Spare fuses are inside the fuse holder; use only Onan-supplied 5-amp fuses.

The generator set control consists nents listed below (see Figure

• Control panel assembly

• Printed circuit board

• Start/Run/Stop switch (S1)

• Fuse (F1}

• Fuse (F2)

• Start solenoid (K1)

• Stop latch relay (K5)

• Fuel valve solenoid (E4)

• Fuel pump (E3)

• Remote start control

• Circuit breaker(s)

• Voltage regulator (VR1)

• Terminal board (TB1)

Control

The control panel assembly consists of:

Printed

board controls run, and stop functions. It is mounted the rear the control panel. It contains nections control; fuse (F1).

Panel

• Printed circuit board

• Start/Run/Stop switch (S1}

• Fuse (F1)

• Fuse (F2)

Circuit

to

the

Assembly

Board

the

engine start, start disconnect/

the engine, generator, and remote start

start-stop switch

(A

(A 1

1)

):

(S1

of

the compo-

7-1

):

The printed circuit

V\i'iring

harness con-

); and the control

of

Fuse (F2): This slow-blow 5-amp fuse protects the

fuel pump circuit from overcurrent conditions. It is removable from the front Spare fuses are inside the Onan-supplied fuses.

of

the control panel.

F1

fuse holder; use only

Start Solenoid (K1}

The

K1

start solenoid opens and closes the circuit between the starter motor and the battery. The starting current load requires that the solenoid contacts have a 300-amp contact rating. minal connects to the 12-volt solenoid coil. studs provide connection points starter cables; the battery B+ stud connection protrudes through the control housing for convenient access.

the

control panel to the outside

A single ter-

to

the battery and

Two

of

Stop Latch Relay (K5}

The K5 stop latch relay latches the generator set when switch This prevents the set from restarting when the

switch is momentarily placed in the STOP position, then released. The K5 relay is located inside the control box.

Fuel

Pump (E3}, Fuel Valve Solenoid (E4}

The E3 fuel

CR9) at the same time the start solenoid

gized, by closure the set is started, fuel pump relay K6

and the fuel pump then receives its current through

a separate connection. Fuel pump power

fied to

diode to prevent current flow

and fuel pump relay

DC

by

S1

is moved to the STOP position.

pump

is

initially energized (through

K1

of

start relay

K4

contacts. After

is deactivated

CR 1 0.

CR9 then serves

to

start solenoid

KS.

as

a blocking

off

is ener-

is

recti-

K1

Start/Run/Stop

switch which starts and stops the The switch

released. not field-replaceable.

Switch

(S1):S1

is

returns to the center (run)

lt

is mounted on the circuit board,

a

oos~tlm

Fuel valve solenoid serves

when the fuel pump

~~~mote

as

a safety measure by blocking fuel flow

Start Control

remote start control enables the generator set

E4

parallels fuel pump E3; it

is

not activated.

deluxe

Circuit AC output from the generator is supplied to circuit

breakers the control housing.

Breakers (CB1

CB1

and CB2, located on the right side

and

CB2)

of

board are encased in the regulator housing with a potting compound. The wiring harness plug-in P4 is treated with a lubricant prior to connection.

Terminal

Board

(TB1) Voltage The voltage regulator helps provide stable output

voltage under varying loads. During initial start the set, the voltage regulator receives from the starting battery, and begins excitation the rotor through leads J4-9/F1 , and J4-1 ter the generator set starts and runs, it provides AC

power to the voltage regulator through leads J4-11 /Q 1 , and J4-12/Q2 for the excitation system.

The AC voltage is rectified to DC voltage, and the

proper

tor in proportion to changes in demand. Reference

voltage is J4-2/L 1 to J4-3/LO.

The voltage regulator is protected from moisture

and other contamination, reducing the risk of com-

ponent failure. The capacitor and the printed circuit

Regulator

DC

excitation voltage is conducted to the ro-

(VR1)

DC

O/F2.

of

current

of

Af-

The AC output power leads from the generator T2, T3, and T4) are connected to terminal board TB1

at terminals L 1 -

AC power wiring harness terconnect wiring to circuit breakers

These leads provide generator output to the voltage regulator for proper voltage regulation, and to

the circuit breakers for power supply to load.

at

TB1

J4

LO.

terminals is tapped by leads

of voltage regulator VR1, and in-

CB1

(T1

of

and CB2.

CONTROL OPERATION

The schematic diagram shown in Figure 7-2 is in-

of

tended as an illustration However, when troubleshooting, always refer to the wiring diagram that corresponds to the model and

spec numbers of the generator set.

the circuit description.

,

~

•

~

,---·----,----D.·~-~--~

I I I I

I I I

¢r

'L_

r--;:::::::::

·1

I I

I

I 5 1 · 2 I

I l!ll I

1

_,_

~~

I

~!f(')

1

e;:

I --

-=;--=--~

I I I I

1

I

I I

I

I I -

~

_ I I

I

ili~

TT

T

'=

cp~<t::

- LU!f

~~J

- 5

«

-1 : "'

111

= =

=-

-:._'--_--=-

REMOTE

START

PANEL

-OPT I OI<AL

~

~.

_1__"·

••

_[~--4

.,.

~

~-=-

--::-$:

I I

i

"'

~:

...

a:li

!!.0-"-.

sz

f 1

RUH

'!

ST~~.

I - _tn.,

-'::.:-::.:-=-

/STOP

SCHEMATIC

DIAGRAM

,--------------------------------l

I

Cf<1

lc

: I

c•L__L

.ll

_____

J1

••

J

'r-

I

tP2

:r~

I

-!fl.,

1

,l

EP~l

______________________

I

~~

P2

:

P2

_,

·i_-----------------------------

__

..

I I I

~

_Rl.

-+------'--~

_,

~~-----;;r~

1

"'

WI

I

..

~-;---------------t---~~----------~~

I 1

sr~r

.E..

Rl

"'!'

CR2

c~

r 1

""

----

.-J!!l•

W:·

1

·~-------------------,-,

,,LLJ

Ptl

,,L)

BUt

LO

UP

-·

'

.,.

--..

,A------------------,

I

I I

I

,,a.

PJO

pr

,,a.

I

I I

,,u_

PJI

:·

I

,,1}

P1~,

,,IJ_

I

J

EXCITOR

______________ ___________

____

LP

SHUTDOWN

____

- I I

,

sh"'"

I

U,p

I

I I

l

______

NOTES

L CO..ONEHTS

OFF

THE

t

IC1

UL!CTIOH

PCI

SHOWN

, I ., I

I g I - I I I

l I " I

~

;.._Ez ~ ;{'

~ y ~

...

I

~ I ~

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I I I I I

I_--

DUTSIDE H£AVY

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Aft£

SHN't

DI!T!

....

HOE

INED ACCQR[)INGI

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I I

I

I I

, I I

Kll

~

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ffi.,

~

A"'

y

~

Sl

L--L--..L---'

DASH FOR

i~

....

y

:;;i

I I I

t..INE

ARE

LOCATED

IIEFERENCE

ONI..

TO

MODEL.

SPEC.

I I

r.

1d

~.:.

;:;

- I

'l=

I I

6B' 1

Y'

Y.

1

]·

I

FIGURE 7·2. BGM/NHM CONTROL SCHEMATIC (MECHANICAL GOVERNOR SETS)

b

Starting

Placing tion connects battery lay. This energizes K4, open (N. (B+)

Connecting sponses:

the

Start/Run/Stop switch in

ground

0.)

contacts

to

the

following:

• N.C. contacts

• Generator voltage regulator

• Ignition coil {T1)

• Fuel

• Start solenoid

pump

B+

• Flashes adequate age

the

residual

buildup.

that

of

K2

relay (K6)

(K1

produces

field,

to

magnetism

the

(B-)

to

the

which

)

closes

connect

generator

the

make

battery positive

following control re-

sure

to

Start posi-

K4

start re-

the

normally

relay

that

there

induce volt-

is

As

lay (K3). put

voltage erator relay choke tion,

opening

pump

Energizing gize K4, nect

B+

(K3). Energizing provides and

S3

De-energizing gize

K1 energizing tor,

which contacts erator

the

from

(1<2).

heater

and

power, rectified by CR1 0.

element

the

fuel solenoid.

K2

opens

and

closes

to

the

generator

an

alternate

ignition module.

K4

start solenoid

K1

disconnects

stops cranking. De-energizing

which

connect

engine

comes

the

generator

This

through a separate

choke and powering

a set

another

K3

closes

B+

opens

and

up

energizes

AC

voltage activates

of

contacts

set

of

start disconnect/run relay

a set

circuit

contacts

K6

fuel

B+

from the starter

E3 and

E4

to

speed,

contacts

of

contacts

to

T1

which

pump

directly

AC

out-

the

gen-

the connecthe

fuel

to

de-ener-

to

con-

which

ignition coil

de-ener-

relay. De-

mo-

K6

closes

to

gen-

• Energizes producing a activated.

• Energizes

B+

nects

• Energizes its N.O. contacts

• Energizes ing fuel

• Energizes pumping fuel to

• Energizes the contacts to switch

Closing the

to

the

starter motor.

tor, which

starting.

to

be

energized

S2

K1

begins

the

ignition coil

spark

when

the

fuel

pump

to

the fuel

the

start solenoid

in

the

solenoid fuel valve (E4), allow-

the

carburetor.

the

fuel

pump

the

stop

latch relay (K5)

to

ground,

through

after

engine

start solenoid

This

to

crank

{T1

),

ignition

relay (K6),

pump

carburetor.

which

and

(K1

starter

{E3},

allows

closure

startup.

contacts

energizes

the

engine

so

module

fuel solenoid.

),

motor

which

of

the

it

can

begin

S3

which

run relay

oil pressure

connects

starter

circuit.

to

open

to

con-

closes

begins

mo-

initiate

is

its

K3

B+

Opening fect lel

with

the

When to

center

Relays (stop latch relay) (start solenoid), relay)

these

on

engine

the

ignition coil.

start-stop switch

(run) position,

K2

are

K4

operation, because

closed

(generator relay), K3 (run relay},

de-energized.

contacts

K3

contacts

are

K4

(start relay)

at

this

which

S1

is

released

the

engine

energized

and

time

has

they

are

in paral-

connect

and

continues

while

relays

K6 (fuel

no ef-

B+

to

returns

to

run.

and

K5

K1

pump

Stopping

Moving start-stop switch grounds

lay K3. from ignition coil T1, and stop latch relay K5. Deenergizing ground. and

S1

resistors This

K5

This

prevents

is

released from

R1

opens

allows its N.C. contacts

prevents K3 from being energized,

the

set

S1

to

the

and

R2

to

de-energize

its contacts

from restarting

the

STOP

position.

STOP

to

disconnect

to

when

position

run re-

B+

close

to

switch

Starter

When (82)

the

closes

lockout-Run

engine

starts,

to

connect battery

the

low

oil pressure switch

ground

to

the

run re-

Without output deenergizes. All ergized

ignition,

voltage drops,

position following set shutdown.

the

engine stops.

generator

components

As

return

the

relay

to

their

generator

K2

also

de-en-

---~-

~

-------

STATOR

HOU~

BRUSH

BLOCK

./ASSEMBLY

~;------~

/ASSEMBLY

J3

VOLTAGE

REGULATOR

CONTROL PANEL

ASSEMBLY

FIGURE 7-3. BGM/NHM CONTROL COMPONENTS

(MECHANICAL-GOVERNOR GENSETS ONLY)

7-6

G1212-5

BATTERY,

STARTER AND

GENERATOR

WIRING HARNESS

CONNECTOR (P1)

ENGINE WIRING

HARNESS

CONNECTOR (P3)

REMOTE CONTROL

WIRING HARNESS

CONNECTOR (P2)

RGURE

START/STOP SWITCH (S1)

7-4. BGM/NHM CONTROL PCB ASSEMBLY (A1)

ES1774

7-7

CARBURETOR

WITH AUTOCHOKE

(AUTOCHOKEIFUEL

PUMP RELAY K4 BEHIND

CARBURETOR)

SPARK PLUGS

FRONT

AND

(fOP

ACCESS

REAR PLU )

TO

NEGATIVE (-)BATTERY

.25 INCH HOSE (GASOUNE)

·~~V"

CABLE CONNECTION

FUEL

INLET

.25 INCH NPTF (LPG)

AC

OUTPUT LEADS

SO

INCHES

M)

(1.5

LONG

OIL DRAIN KNOB

(3/8 INCH SQUARE DRIVE)

FIGURE

7D5.

BGM/NHM GENERATOR SET (ELECTRONIC-GOVERNOR VERSION)

CONTROL DESCRIPTION

(Electronic

The generator set control consists nents listed below (see Figure 7-5):

• Control panel assembly

• Printed circuit board

• Start/Run/Stop switch (81)

• Fuse

e Start solenoid

• Fuel pump {E3) and fuel valve solenoid

• Remote start control (optional)

• Circuit breaker(s)

• Voltage regulator (VR1)

• Terminal board (TB1)

(Fi)

governor

(A

1)

{K1

)

CB1

and CB2

gensets)

of

POSITIVE ( +)

BATTERY

CONNECTION

(SPEC D GENSET SHOWN)

the compo-

These components are described below. The des-

Ignations In these descriptions refer control board schematic In Figure 7-7; they not

In Control Panel Assembly

The control panel assembly consists of:

M1801-3s

• Governor controller board {A4}

• Fuel pump/autochoke fuse (F2) (Spec

• Fuel pump/autochoke relay (K4) (Spec

only

necessarily correlate

any

other

• Printed circuit board

• Start/Run/Stop switch (S1)

• Fuse (F1)

schematic

with

the designations

or

wiring diagram.

(A

1)

D)

to

D)

the

do

1·8

Printed

board controls the engine start, run, and stop functions. It is mounted behind the control panel. It includes the following parts:

The printed circuit board is not repairable in the field.

Circuit

• Wiring harness connections to the engine, generator, governor control board and remote start control

•Start-stop switch (S1);

• Control fuse (F1)

• Relays K1, K2 and K3 (see schematic)

Board

(A 1

):

The printed circuit

E3

is activated through K4 contacts.) See the set

11

schematic diagram, in Section

Remote Start Control

The optional remote start control enables the user to start and stop the set from a remote location. The deluxe control includes a running time meter and battery condition meter.

Circuit

The set AC output is supplied for operator use through circuit breakers the right side

Breakers (CB1 and CB2)

of

the control housing.

(A1

;P2/J2) {optional)

CB1

of this manual.

and CB2, located on

Start/Run/Stop

switch, mounted and stops the generator set. The switch returns to the center (run) position when released.

Fuse

(F1): This slow-blow 10-amp fuse protects

circuit board A 1 from overcurrent conditions. It is

removable from the front of the control panel. Spare fuses are inside the fuse holder; use only Onan-supplied 1 0-amp fuses.

SWitch

on

(51):

S1

is

a SPOT rocker

the circuit board, which starts

Start Solenoid (K1)

Start solenoid tween the starter motor and the battery. Two termi-

nals provide connection points to the battery and

starter cables; the battery B+ connection protrudes through the control panel to the outside trol housing for convenient access.

K1

opens and closes the circuit be-

of

the con-

Fuel Pump (E3)

Fuel pump

start solenoid

E3

is energized at the same time that

K1

is energized. (Spec D gensets:

Voltage Regulator (VR1)

The voltage regulator helps stabilize output voltage under varying loads by providing age to the generator rotor. AC voltage is rectified to

DC

voltage, and the proper DC excitation voltage is conducted to the rotor in proportion to changes in demand.

DC

excitation volt-

Terminal Board (TB1)

AC output power leads

generator are connected to terminal board terminals to voltage regulator

and CB2.

L 1 -

LO.

T1

, T2, T3, and T 4 from the

Wiring harness

VR1

and circuit breakers

J4

connects

TB1

CB1

at

{Spec D gensets)

Fuel Pump/Autochoke Relay and Fuse

(K4 and F2)

Relay K4 opens and closes the circuit that powers fuel pump E3 and autochoke K1. A connection to control assembly A 1 energizes K4. K4 is located on the rear

of

the air cleaner adapter.

7-9

FIGURE 7·6. GOVERNOR CONTROLLER BOARD

A4

Governor

Governor controller board set mounting tray. It accepts inputs from the electronic ignition module and

B+

and ground connections power the board.

Figure 7-6.

Governor controller board that drives

moves the carburetor throttle to maintain

speed

module and the governor controller board to shut the engine off der

the following adverse conditions:

•If

• If genset speed goes beyond

Controller

Board (A4)

A4

is located on

the

oil pressure sensor.

A4

outputs a DC voltage

the governor actuator, which in turn

of

1800 RPM. The inputs from the ignition

oil pressure sensor can signal

power

(B+) is lost

to

the controller

2700 RPM

the

an

gen-

See

engine

the un-

•If

oil pressure switch S2 closes

•If

the signal from the ignition module stops

•If

genset speed goes below 1760

seconds

Under board controller board is a non-serviceable component.

all these circumstances, governor controller

A4 shuts down the genset. The governor

RPM

for 30

CONTROL OPERATION

The schematic diagram shown in Figure 7-7 is intended as However, when troubleshooting, always refer to wiring diagram that corresponds

spec numbers

an illustration

of

the generator set.

of

the circuit description.

to

the model and

the

7-10

~

i"

......

1

,-------

1

I

1

I

·-·--·-·- I

c---

:.

•

I...

w

1

~

i ' " I • I I

. lo-

T9.

_,

i ' '

I ' ! ,J,, ,"w.J I

I I I

r

I

l

I

-

·-·-·-·--·-·-

"---'

l

·---

,-----==-===::c

I.

c---

Is

I

ffi

----t---

I I"'

9

---~-

1

REMOTE

!f

::;

1 " I -"'I '

I:;

~

z I .

y.

,~,,.:::"'"'"''.;;;:-J

,_.,I

I I

I c

STAR'fl

I

--'-----+-

·-·-·

___

I

. I

!'

".J._

I I 1

r---

I 1

l'l

\'

_.,

,••I

"

I I d

" "

---'>1

- - _I

'

I I r '"""""' I I

_.,I

.,1

.,

-----

">L

--------

-----

----

-·---·----

---

-;;1"

·"I

•"

:·I~"'""'""'""

....

/'

,"I

,,1 " I I I I I

__

------

>'---

"·

'-'

""'"""

I " I I

oo~~~

-----.-..,

I 1

: :

rc--

,

',1

----------,

>"----

,.

)-'--

"•

'\

I

I IOVFR SPEED I s { I I I

I I I I I

I I : I : I

j

I I :

I>-"----

NOfES,

1.

2.

-

-----

------"

0

GOVERNOR

""

~

'"

'"""'I

""'"

----~-L-~

COMPONENTS

OUT'S I DE

OfF

THE

PCI

D&TEMfiiiiiNED

HEAVY PtWfTOM l I

LOCATED

tct 5ElEI:TION IS

"1

• I " I • "

113 I 15

E~

~-

.,

' ' "

' !

1 I I I I

! I I I

I I I I I

AHO

IJIE

SHDIIIIN

AOOORDINCJ

I I

1 l

I "

I T

0 0 I 0 I

= I :! I

FOR

)!.!

I"

N1!

TO

M!

REF

VI

"•

_

...,DEl

"'

I i I

I

"'

'

I',!

Y"

1 1

_._

_

' I

ONt.

Y.

SPEO.

~

-T--

I

:

I

_;

I

FIGURE

7·7.

BOM/NHM

CONTROL

SCHEMATIC

(ELECTRONIC

GOVERNOR

SETS)

Starting

Moving the Start/Run/Stop switch tion connects battery ground (B-) and A 1-K1. Normally-open contacts

close, connecting

•

Governor

•Relay

• Ignition coil

• Start solenoid of A 1-K2

• Relay K2 (through resistors

Normally-open contacts on relay connecting

• Voltage regulator

NOTE:

Pre..Spec

B+

to

the

control board

K4

T1

K1

(through N.C. contacts

relay

B+

to

the following:

VR1

D generator sets have fuel pumps

that are powered directly rather than through

to

the Start posi-

to

relays A

on A 1-K3

following:

A4

R1

and R2)

K1

close,

(to build-up exciter)

1-K3

K4 contacts. Otherwise their control functions are Identical

to

those described here.

When

the

ground to relay opens another ter

Starter

When

switch is bypassed until

ing speed. Normally,

switch is open. released engine continues opening the B+ line to control board, start solenoid, fuel valve solenoid. gized, and A start solenoid from being activated while the set is running. tinue

solenoid, ignition coil

governor

generator

the

exciter

circuit

K3

is

de-energized.

Lockout-Run

the

and

Another

to

provide

control board

reaches

A 1-K2. A

circuit

to

the fuel

engine

When

returns

to

At

1-K2

contacts open which block the

set

power

A4

1150

1-K2

contacts open, which

after

initial start and closes

pump

cranks, the

the

engine reaches operat-

with

the engine running, the

the

StarVRun/Stop switch is

to

center

run. A

the

and

1-K3

the

field exciter,

same

of

to

time, A

K2 contacts close

the

fuel pump, fuel valve

governor

determines that

RPM, it connects

and ignition coil af-

low

oil pressure

(Run) position, the

is de-energized,

governor

pump

and

1-K2

is

to

controller.

fuel

ener-

con-

The following control responses take place:

•

Governor

to

an

K4

relay contacts close

• pump

The

• ism

gized.

• Ignition coil

ing sparks vated.

• Start solenoid to

the

for

starting.

1,\1

Solenoid tuel valve

control board A4

open position

E3 and fuel

field

is

flashed

to

T1

when

starter motor, which cranks

releasing fuel

after

pump to

provide residual

is energized,

ignition

K1

is energized, connecting

moves

a 1-second delay.

to

provide

solenoid E4.

buildup.

module

E4

(see Figure

to

the

power

magnet-

J1-3

is

to

begin

produc-

83

the

carburetor"

throttle

to

fuel

ener-

is acti-

B+

engine

iS

(On electronic-governor can

be

started and run, pressure switch is disconnected as

this lead is not grounded.)

Off

the

control board, bridge rectifier C R 1 0 receives AC voltage through provides DC voltage tor

R1

to

charge D gensets, the B1/B2 connection is paralleled power

choke. directly

the

On

by

choke

Spec

B+

voltage.

the

D sets, the autochoke

generator

even

generator

through

starting battery.

heater

element, opening the

sets, the engine

ifthe

lead

to

the

low

or

missing,

leads

battery charge resis-

81/82,

On

pre-Spec

is

powered

as

long

Stopping

Moving start-stop switch grounds actuator 'fuel dlsconnecting :gnition coil.

resistors A 1-R1 responds

to

the engine. Relay A 1-K2 Is de-energized,

the

by

B+

S1

to

the

STOP

and

A 1-R2. The

closing the throttle, cutting

line from the fuei

position

governor

pump

oil

and

to

off

and

shutdown.

,

---,"----

.1._.--:;::-

~

-,_,

-~-------~----------

"----

~

~~

~---

------~---------l

____

.J

~CIRCUIT

~

.......

~.,

~

GOVERNOR

CONTROLLER

ASSEMBLY

(M)

VOLTAGE

REGULATOR

ASSEMBLY

(VR1)

MAGNETIC BREAKERS

(CB1, CB2)

FIGURE 7-8. BGMINHM CONTROL COMPONENTS

(ELECTRONIC-GOVERNOR GENSETS ONLY)

7-13

G1212-4

BATTERY, STARTER, ENGINE

AND GENERATOR WIRING

HARNESS CONNECTOR (P1)

FUSE (F1)

REMOTE CONTROL

WIRING HARNESS

CONNECTOR (P2)

START/STOP SWITCH (S1)

FIGURE 7-9. BGM/NHM CONTROL PCB ASSEMBLY (A1)

ES1774

CONTROL TROUBLESHOOTING

Use the following troubleshooting guide to help locate problems related to the control circuits. Figures

7-1

and 7-5 show the location of most of the control components. Refer to the appropriate wiring diagram/schematic in Section of

all terminal connections.

IAWARNINGI Many troubleshooting procedures

vere

persona/Injury

electricity,

and

precautions on Inside

or

death.

machinery hazards

cover

8 for the location

Only

qualified service should

page.

Trouble Possible Cause

Engine Does Not Crank

1.

Control fuse

2.

If engine cranks at set but not at

remote control panel, fault is due to: a. PC board P2/J2 connection not

secure.

b.

Open circuit in remote control.

c.

Remote start switch faulty.

F1

may be open.

The troubleshooting guide is divided into sections. After identifying the problem, refer to the guide for the possible cause and the recommended correc-

tive action.

Many

of

the components listed In the following procedures are governor Marquis gensets. Follow dures that apply Iced.

present

personnel

not

present on the newer, electronic

only

to

the particular genset being serv-

hazards which can result

with knowledge

of

the proce-

in

se-

fuels,

perform service procedures. Review safety

Corrective Action

1 . Replace fuse

Onan-supplied fuse only.

2a. Ensure that wiring harness jack

connections are fully seated to

2b. Check for continuity and correct if circuit

is open.

2c. Replace remote start control switch.

F1

if

open with

PC

board.

3.

If

engine cranks control panel but not at set, fault is due to faulty

4.1nsufficient voltage for cranking due to:

(See Low Battery Voltage also.)

a.

Battery not charged.

b.

Terminal connections loose or

dirty.

c.

Battery cable too small.

at

S1

remote

switch.

3. Replace PC board A 1.

of

4a. Check condition

or

replace.

4b. Clean and tighten all connections at

K1

battery, motor.

4c. Increase cable size.

lA

WARNlNG

can

result

nect

the

start solenoid, and starter

I

Short

In severe persona/Injury. Discon-

negative(·)

battery and recharge

circuiting

battery cable

tery terminal before servicing.

7-15

the battery cables

at

the bat-

lA wARNlNG! Many troubleshooting procedures present hazards which can result In se-

or

vere persona/Injury

and

electricity,

machinery hazards should perform service procedures. Review safety

dea_th.

precautions on Inside cover page.

Only qualified service personnel with knowledge

of

fuels,

Trouble

Engine Does Not Crank

· Engine Cranks But Does Not Start

Possible Cause

5. Connect a voltmeter between terminalS and ground. Check for battery voltage when START position. If voltage is present, fault is due to:

K1

a. b. Defective c. Defective starter.

6. If voltage is not present as described in step 5 test, fault is

due to:

a. Open circuit between

and control PC board.

b. Defective control PC board.

on the start solenoid

S1

is placed in

start solenoid not grounded.

K1

start solenoid.

K1

relay

7. B+ fuse (F1) is open.

to

worn

1 . Faulty ignition due

fouled spark plugs, faulty plug wires, faulty ignition coil control module.

or

Corrective Action

5a. Tighten solenoid bracket mounting

screw.

K1

5b. Replace 5c. Refer to

test and service procedures.

6a. Check for continuity and correct if circuit

is open.

6b. Replace control PC board.

start solenoid.

Electric Starter (Section 6) for

7. Replace fuse.

1 . Refer

test and service procedures.

to

Ignition System (Section 6) for

2. Faulty tuel system due to low fuel level in tank, supply valve

not open, sticking choke, faulty fuel pump/fuel solenoid, carburetor mixture screws incorrectly adjusted.

3. Bad reiay K4 and/or fuse F2

4. Connect a voltmeter between

1

I

positive(+)

il'

coil

and_

voltage when 81 is placed

tery

in

START

1

1 not present, fau

I a. Open

terminal

ground. Check for bat-

position.

It

due to:

E1

coil-to-control circuit.

or

E1

ignition

if

voltage

j Defective control PC board,

I

to

2. Refer and service procedures.

3. Replace relay and/or fuse.

4. a. Check for continuity and correct circuit is open.

4. b. Test/replace control PC board.

Fuel System (Section 6) for test

6

if

IAWARNINGJ Many troubleshooting procedures present hazards which can result In se-

or

vere persona/Injury

death. Only qualified service personnel with knowledge

of

fuels,

electricity, and machinery hazards should perlorm service procedures. Review safety

precautions on Inside cover page.

Trouble

Engine Cranks But Does Not operating properly (electronic

Start governor sets)

Engine Starts But Stops When Start Switch is Released

Possible Cause

5.

Governor controller board not

1.

Low oil pressure switch S2 not opening due to: a.

Low oil level.

b.

Open circuit between switch

and governor controller.

c. Defective low oil pressure

switch.

d. Low oil pressure.

2.

(Spec A sets only)

Ignition relay K5 contacts not

opening due to:

a.

K5 relay circuit open.

b.

Defective K5 relay.

3.

Output voltage from generator

not being supplied to control

due to:

a.

Open circuit in wiring between generator and control.

b.

No output voltage from generator.

Corrective Action

5.

Verify that throttle goes wide open after1 second of cranking. If governor controller. Check electrical

connections to actuator, governor control,

ignition. If board is defective, replace.

1 a. Check oil level and add oil if low. 1b. Check for continuity, correct

open.

c.

Replace low oil pressure switch.

1 1 d. Refer to Section 6, Troubleshooting, for

procedures to follow.

2a. Check for continuity and correct

circuit is open.

2b. Replace K5 relay.

3a. Check for continuity and correct if

circuit is open.

3b. Refer to

and service procedures.

Generator section for test

so,

problem is not

if

circuit is

if

Low Battery Voltage

4.

Defective control

1.

Weak

due to:

a.

b.

c. Improperly wired battery.

2.

Load connected to battery while set is turned off.

or

discharged battery

Low electrolyte level in battery. Long periods

PC

of

non-use.

board A 1 .

7·17

4.

Replace PC board A

1 a. Replenish electrolyte and recharge

battery.

1 b. Connect a separate battery charger to

bring battery up to full charge.

1

c.

Reconnect and check battery connection.

2.

Turn off/disconnect load and recharge battery.

1.

!A WARNING I Many troubleshooting procedures

vere

persona/Injury

electricity,

and

precautions on Inside

or

death. Only qualified service

machinery hazards

cover

page.

should

perform service procedures. Review safety

present

personnel

hazards which can

with knowledge

result

of

In sefuels,

Trouble Engine Starts

And Runs; Then Stops. Set Restarts

Immediately Set Restarts After Cooling

Down

REMOTE CONTROL (if equipped)

Run Lamp, Time Meter, Battery Con- 1 dition Meter

Does Not Operate

or

or1

Possible

Cause

1. Fuel level is below generator set

fuel pickup tube is low.

2. Dirty fuel filter restricting fuel flow.

or

oil level

3. Faulty ignition module.

4. Contaminated fuel.

1. Open circuit between control

A1

and

board of

remote terminal 6 connector plug P2/J2 and start-stop switch S2.

I

terminalS

or

5 on

2. Open circuit between ground

terminals on lamp

and terminal 1 start-stop switch.

on

or

meters

remote

5

Corrective

1. Check fuel and oil levels and refill as

necessary.

2. Clean fuel filter. Refer to Fuel System (Section 6) for test and service procedures.

Action

3. Replace ignition module.

4. Refill tank with fresh fuel.

1. Check for continuity and correct

circuit

2. Check for continuity and correct circuit

is

open.

if

3.

If battery condition meter and

run lamp does not operate, time meter is defective.

4.

If

time meter works but battery condition meter connect a voltmeter between the

positive terminal charge the following to determine fault: a.

If reading equals battery

voltage minus 1 0 voits, battery condition meter is

b.

If battery voltage minus zener

work

but time meter

does

not operate,

on

battery

meter

and ground. Use

aev·ectnt

reading does not equal

1 0

diode is defective.

3. Replace time meter.

4a. Replace battery condition meter. 4b. Replace zener diode.

.:.

IAWARNINGI Many troubleshooting procedures present hazards which can result

or

vere persona/Injury

death. Only qualified service personnel with knowledge

of

In

se-

fuels, electricity, and machinery hazards should perform service procedures. Review safety precautions on inside cover page.

Trouble

REMOTE CONTROL

(if equipped} Run Lamp,

Time Meter,

or

Battery Con-

dition Meter

Does Not

Operate

Generator Set Does Not Stop After Switch Is Pushed to Off

Always

remove

a

before ping

-Ito down.

few

load

minutes

stop-

to

allow

cool

Possible Cause

5. Meters and switch function properly but run lamp does not illuminate. Lamp (internal to switch) is burned out.

6.1f remote switch functions

OK (starting and stopping genset) but meters and run lamp do not operate, current sensing resistor

R4 on control board A 1 has opened, caused by a short in the remote control wiring between

control board P2/J2 terminal 6/5 and remote control time meter,

run lamp/battery condition meter.

1 . Faulty set control start/stop

switch (S1)

2. (Spec A sets only) K5 relay not energizing due to:

a. Open circuit to K5 relay coil. b.

Faulty K5 relay.

Corrective

Action

5. Replace remote start-stop switch S2.

of

6. Check for continuity

remote wiring harness and wiring on remote control series with terminals 6 and

5.

Replace

wiring of control circuit.

1 . Check start/stop switch and replace

if defective.

2.

a.

Check for continuity and correct if circuit is open.

2.

b.

Replace K5 relay.

in

7-19

TESTING CONTROL

Confirm that control board A 1 is faulty before re- placing perform the following tests.

it. Use a DC voltmeter and an ohmmeter to

BOARD

A 1

1. Disconnect the negative (-) battery cable.

2. Remove the control box cover (Figures

and 7 -5) and separate it from control board A 1 by removing the four screws on the back of the board.

7-1

3. With an ohmmeter, check for electrical conti-

nuity across each

the

on place the socket portion

has a measurable resistance (greater than

zero ohms)

control board (Figures 7-2 and 7 -6). Re-

or

P1/J1

has begun to corrode.

and P3/J3 connector

of

each connector that

4. Reconnect the battery and try to start and run

the set.

5. If the engine does not crank, measure voltage at connector P1-2 while pressing the panel start switch (the negative (-) test probe of the voltmeter should be grounded at connector

P1-8). If the voltmeter indicates zero volts, replace control board A 1. If the voltmeter indicates at least the control board. Go back to the

9 volts, the problem is not with

Trouble-

shooting Guide.

6. If the engine cranks, but does not start, meas-

ure voltage at connectors P3-3 and P3-6 while

(-)

the engine is cranking {the negative probe connector P1-8). Replace control board the voltmeter indicates zero volts at either con-

nector. If the voltmeter indicates at least

at both connectors, the problem is not with the

control board. Go back to the

of

the voltmeter should be grounded at

Troubleshooting

Guide.

7. If

the

engine starts, but stops when the Start

switch is released, the problem could be with

the low oil pressure switch or generator (no

voltage). Go back to the

Guide.

sure switch and generator are functioning properly.

8. Reassemble the control board and cover.

Replace control board A 1 if the oil pres-

Troubleshooting

test

A 1

9 volts

if

7-20

Section 8. Generator

GENERATOR/CONTROL COMPONENT

DESCRIPTIONS

The generator and its control components consist of the following elements (see Figure

• Control printed circuit board (A

•Brushes

• Rotor

• Stator and housing

• Terminal board (TB1)

• Voltage regulator {VR1)

• Circuit breakers

• Wiring harness to load

The ignition module and rotor are mounted inside the generator; for this reason, their removaVreplacement are described in this section.

(CB1

/CB2)

8-1

1)

} :

K1,

Start solenoid pump E2 are activated. After initial start, control board is activated, opening the exciter circuit and closing another circuit to the governor control board, fuel pump and ignition coil after energized. Governor control board A4 is energized, which moves the throttle to an open position.

solenoid fuel valve

E3

K2

K3

and fuel

on the

is de-

Brushes

DC

excitation voltage brushes and rotor slip rings to the rotor windings. The brush block assembly consists of a single brush block with two brushes. The brush block

mounts directly over the rotor slip rings inside the

generator housing, and may be accessed by re-

moving the small plate at the rear of the housing.

is

induced through the

Rotor

Control Printed

Circuit

Board (A 1)

(Mechanical-governor generator sets)

The starting battery supplies initial excitation voltage to the generator rotor. While the engine cranks, battery

N.C. contacts of generator relay K2 (on control board A 1 ), through voltage regulator VR1, to the brushes and slip rings of the rotor. When the engine starts and generator voltage builds up, generator relay K2 is energized, opening the N.C. contacts in the battery B+ circuit to the voltage regulator and closing a set of disconnect/ run relay K3 circuit of board A circuit keeps relay K3 energized while the set is in operation. If relay K2 becomes de-energized, the

set shuts down.

Control Printed

DC

voltage is supplied through the

N.

0.

contacts in the start

Circuit

Board (A 1)

1.

This

(Electronic-governor generator sets)

Moving the Start/Run/Stop switch to the Start posi-

K3.

K1,

VR1

Nor-

N.C.

(to

tion connects battery ground (B-) to relay

on

K3

mally-open contacts

governor control board A4 (see Section 7), fuel

E2,

pump

contacts of K2 relay, voltage regulator

build-up exciter), and relay K2 (through resistors

R1

and R2). The field (rotor) is flashed through the

N.C. contacts

ignition coil

of

K2 . Ignition coil

close, connecting B+ to

E1,

start solenoid

E1

is energized.

The 4-pole rotor provides the rotating magnetic

field that is required to generate an AC voltage po-

tential in the stator windings. The

quired for field excitation is supplied through two slip rings on the rotor shaft.

of

The engine end the engine crankshaft with a tapered seat/shaft coupling and through-bolt. The outer end of the rotor is supported by a single bearing that is pressed onto the rotor shaft. The bearing slip-fits inside the generator housing.

Cooling airflow for the generator is provided by a centrifugal fan that mounts on the inner end of the rotor shaft. The fan also serves as a mount for the starter ring gear.

the rotor is connected directly to

DC

current re-

Stator and Housing

During genset operation, AC current is produced in the windings routed into the set control housing compartment, for control component connection as follows:

• Leads T1, T2, T3 and T4 to terminal board TB1.

• (Mechanical-governor sets) Leads

to control board A 1, to rectifier

electric choke, and for battery charging.

of

the stator. Stator winding leads are

B1

and B2

CR1

0, to the

• (Electronic-governor sets) Leads CR

rectifier battery charging through R1.

• Leads

wiring harness J4, for excitation

voltage from stator is rectified VR1).

The stator mounts inside the generator housing and is held in position with clamps and capscrews. A series

housing allow cool ing for generator cooling. vides a mounting for the engine starter, rear rotor bearing, exciter brush block, control components, and fuel pump. assembly bolts to

of

10, to the electric choke, and for

01

and

02

to voltage regulator VR1,

air

intake openings in

air

to

be

drawn inside

The

complete stator and housing

the

engine-to-generator adapter.

81

of

rotor. (AC

to

DC voltage in

the

end

housing

and

the

also

82

of

the

hous-

pro-

to

Terminal Board (TB1)

potting compound. The wiring harness plug-in is treated with a lubricant prior to connection.

Circuit

AC breakers C81 and the ers quency. Refer to dering replacement parts.

Wiring Harness

A wiring harness is provided to connect to per protected with flexible conduit from the set control housing to the switching/disconnect device, which must Load conductors are black, neutral conductors are white, and

Breakers

output

control housing. Ampere rating

may

the

wire,

from the generator is supplied to circuit

differ, depending

electrical system. All leads are stranded cop-

to

withstand vibration. The leads must be

be

provided by the vehicle manufacturer.

the

(CB1

,CB2)

C82,

located on the right side

of

these break-

on

the set modeVfre-

the

proper

to

Load

ground conductor is green.

Parts Manual when or-

the

P4

of

genset

The AC output T2, T3, TB1

AC

wiring harness terconnect wiring to circuit breakers C81 and

These leads provide generator

age regulator for proper voltage regulation, and the circuit breakers

Voltage

The voltage regulator helps provide stable output

voltage

the set, the voltage regulator receives DC current

from

the rotor through leads J4-9/F1 , and

ter the to the voltage regulator through leads and voltage is rectified

DC excitation voltage is conducted

proportion to age is

The voitage regulator and contamination, {educing

'"'"'''"'eo'"l'

and

at terminals L 1 -

power

under

the

genset

J4-12/02

J4-2/L

failure.

power

T4) are connected to terminal board

at TB1 terminals is tapped

,.14

Regulator

varying loads. During initial start

starting battery, b-egins excitation

starts and runs, it provides AC

for

changes 1 to J4-3/LO.

The

leads from

LO.

of

voltage regulator VR1, and in-

for

power

(VR1)

the

excitation system.

to

DC voltage,

in demand. Reference

is

protected from

capacitor and the printed circuit

the

generator

by

leads

C82.

output

supply to load.

regulator housing with a

to

J4~

1 O/F2. Af-

J4-~ 1

and

the

to

the

risk nom-

the

power

The

proper

rotot

moistur~e

(T1

of

volt-

to

of

iQ1

AC

in

volt~

,

Refer to Section the wfring diagram/schematic that corresponds to the specific genset

lems. When

rotating field (rotor) is momentarily connected to

battery positive age build-up. As the engine starts and speed increases, the ture winding

voltage.

mately

erned speed.

,

Voltage regulator

provide a stable

load conditions. Leads from J4-2

these leads sense voltage changes

the generator.

The

voltage regulator, depending on load. voltage

;egulator Increases DC excitation voltage ro-

'mting

GENERATOR OPERATION

the

wiring diagrams and schematics in

11

while reviewing this text. Always refer to

when

the

start-stop switch is moved to START,

(8+)

to provide magnetism for volt-

the

rotating field induces an AC voltage in

stator windings. AC voltage from

(01,

02)

AC

voltage output stabilizes

128

volts when

VR1

AC

output voltage

and -3

sensing leads provide reference voltage to

are

connected

field proportionate

field

current

troubleshooting prob-

the

quadra-

is

rectified for field excitation

at

approxi-

the

engine reaches gov-

enables the generator

under

VR1

to

terminal board TB1:

of

to

the

!oad, continuously

as

load changes,.

varying

wire harness

the

load on

the

to

the

Efficient set performance depends frequency (engine speed) regulation. chanical governor generator set, output load changes can significantly decrease or increase engine speed. If the governor does not maintain

on

voltage and

On

the me-

proper engine speed, too large a burden may be imposed to be supplied and troubleshooting is discussed manual.

on

the voltage regulator for proper current

to

the load. Governor adjustment

in

Section 6 of this

,,

8-3

RESISTOR

(SPEC C GENSETS}

R1

RESISTOR

RESILSOA

R7

Ra

00

•

~

GENERATOR

HOUSING \ •

0-RING

STATOPRS CLAM

THRO'l?~'l.ocT

"\l~~~~

~-

'"""

~...;.

""-._

--

...&11--

,;.J.))"\

-------:::::-~-

<-~

'

,......._

TERMINAL

--~LOCK

.......,.

11

-~

TB1

~

""-~----

\ . I

~;~

<~https://manualmachine.com/

~~

~

'.......

"-

'>

'""

-~

BRUSH

BLOCK ELECTRONIC GOVERNqR

ASSEMBLY CONTROL

BOARD

A4"

/

..nt~~~~LATOR~r-

o<"-~

'-

.....

->

MOUNTING

~

BRACKET

-

----------

-~

• , , CB1, CB2

::::::::<

~CIRCUIT

BREAKERS

~

~RELAY

BRACKET

ASSEMBLY*,

~

F~D~~~~f

''>

-------

------

\

'0.

START

SOLENOID

K1

WIRE

TO LOAD

~

L-ESS

ONTROL

~OARDA1

,/

liff?~l~

CONTROL

v'

FUSE

F1

FIGURE

SLIP

RINGS

8·1. GENERATOR CONTROL COMPONENTS

*MECHANICAL-GOVERNOR

**ELECTRONIC-GOVERNOR

GENSETS ONLY

G1212-7C

GENSETS ONLY

GENERATOR TROUBLESHOOTING

This troubleshooting guide provides solutions to many common generator problems. Figure location minal connections. If these suggestions do not help, contact an authorized Onan service representative.

Trouble

No AC Output Voltage Note: This

condition may

cause the generator set to stop when

start switch S 1

is released.

of

the generator components. Refer to the wiring diagrams/schematics in Section

IAWARNINGI Many troubleshooting procedures present hazards which can

persona/Injury

vere electricity,

and

precautions

on

Possible Cause

1. Open circuit breaker.

2. Open circuit between voltage regulator and brush block.

3. Open circuit between generator windings regulator.

or

death. Only qualified service personnel with knowledge

machinery hazards

Inside

cover

(01,

02)

page.

and voltage

should

perform service procedures. Review safety

Corrective Action

1 . Locate cause of overload and correct

as required. Reset breaker.

2.

Check for good wiring connections and correct as required. Check for continuity and correct

3. Check for good wiring connections and correct as required. Check for continuity and correct

if

circuit is open.

if

circuit is open.

11

result

of

8-1

shows the

to locate ter-

In se-

fuels,

4.

Open circuit between terminal block

TB1

and voltage regulator;

wiring harness

5.

Brushes stuck in holder making good contact with slip rings.

6. Defective voltage regulator.

7.

Open, grounded, in rotor

or

J4

stator.

leads.

or

short circuit

not

4. Check for good wiring connections and correct as required. Check for continuity and correct

5.

If there are 12 on the brush block while cranking, then release brushes if jammed

in holder, and clean slip rings

if

dirty. If not, the problem is in the

control or wiring harness.

6. Replace voltage regulator.

7.

Test each component for open,

grounded, or shorted windings and

replace

if

or

defective.

if

circuit is open.

more volts

---

~----------

IAwARNINGI

persona/Injury

vere electricity, precautions

Trouble

AC Output

Voltage Too

Low

or

Too

High

Many troubleshooting procedures

or

death.

and

machinery hazards

on

Inside

cover

Only

page.

qualified service personnel with knowledge should

perform service procedures. Review safety

Possible Cause

1. Engine governor (mechanical) out of adjustment.

2. Brushes worn

contact with slip rings. (Low intermittent AC output voltage.)

3. Poor wiring connections to/from voltage regulator.

4. If generator frequency is within

specified limits but voltage is incorrect, voltage regulator is defective.

5. Open, grounded,

or

rotor

stator.

or

not making good

or

short circuit in

or

present

hazards which can result

Corrective Action

1. Refer to governor adjustments

Section 6.

2.

Check length of brushes and replace

if

worn excessively. Clean

slip rings.

3. Check for good wiring connections and correct as required. Check for continuity and correct

or

if

circuit is open.

4. Replace voltage regulator.

5.

Test each component for open, grounded, replace if defective.

or

shorted windings and

in

se-

of

fuels,

in

replace

Noisy generator

1. Loose brush holder.

2.

Worn generator end bearing.

3. Rotor and stator rubbing together

due to: a. Varnish lumps. b.

Rotor misaligned with crankshaft.

1. Tighten brush holder.

2. Replace end bearing.

3a. Check for varnish lumps between

rotor and stator, remove as required.

3b. Follow specified assembly procedures

to correct rotor to crankshaft alignment.

8-6

IAWARNINGI Many troubleshooting procedures

persona/Injury

vere

electricity,

and

precautions

on

or

death.

Only

machinery hazards

Inside

coverpage.

qualified service should

perform

present

hazards which can

personnel

with knowledge

result

service procedures. Review safety

of

In sefuels,

Trouble

Generator Overheats

Possible Cause

1. Generator overloaded due to defective circuit breaker.

2.Airflow restricted due to dirt debris covering vent openings in stator housing.

3. Stator windings covered with oil or

dirt.

or

4. Open, grounded,

or

rotor

5.

Defective voltage regulator.

stator.

short circuit in

or

Corrective

1. Remove part circuit breaker.

2.

Clear away all dirt

3.

Clean stator windings.

4. Test each component for open,

grounded, replace if defective.

5.

Replace voltage regulator.

Action

of

load and replace

or

debris

or

shorted windings and

as

required.

8-7

GENERATOR SERVICE

This section describes generator disassembly/assembly procedures. Refer to Figure

8-1

to locate

and identify the various generator components, and the diagrams in Section

11

for wiring intercon-

nect information. Generator

Disassembly

Procedure

1. After allowing the engine to cool, drain the en-

gine oil while the genset is mounted in the vehicle.

2. Remove the set from the vehicle and place it on a sturdy work bench. Refer to Section 5 this manual for set removal procedures.

3. Remove the top cover from the generator set.

4. Remove the carburetor and intake manifold to

provide clearance to lift the generator stator

assembly. Disconnect the following parts:

• choke heater lead wires

• throttle linkage (mechanical governor: at carburetor} (electronic governor:

•

fuelline

at

actuator clip)

• crankcase breather hose

• air preheater tube

Remove the intake manifold screws, and lift off

the carburetor and intake manifold

sembly. Refer to the

Fuel System description

as

in Section 6 for detailed removal procedures and important safety instructions.

5. Disconnect the leads to the charge resistor, the low oil pressure cut off switch, and the B+ terminal on the ignition coil.

6. Remove the brush block cover and disconnect the

F1

(+)(outboard) and F2 (-)(inboard) lead

wires from the brush block terminals.

7. Pull each brush outward from the holder, and at

the same time insert a piece

the small hole in the end

of

stiff wire into

of

the stator housing

of

an as-

(see Figure 8-2). Carefully guide the wire through the brush block, then release each brush. Verify that each brush is held off the slip rings

by_

the wire.

lA CAUTION! The brushes

during disassembly

If

not

will

held

be

damaged

off

the

slip rings. Make certain wire Is In place before removing

FIGURE 8-2. BRUSH BLOCK ASSEMBLY

8. Remove the two control panel screws from the housing, lift off the control panel and disconnect plug/jack connections

the control printed circuit board.

9.

Place a 3/8

rotor through-bolt. Use a rubber mallet and

sharply strike the allen wrench so the throughbolt is driven in a counterclockwise (viewed from generator end) direction. Several sharp taps should break loose the generator.

stator

inch

allen

assembly.

BRUSH ,

LEAD WIRE

P1/J1

wrench

...

HOLE

in

the

~

G1178s

and P3/J3

head

of

the

8-8

UFTING

EYE

~T(9/16-12j

G1176-2

15. Remove the four capscrews, lock washers, and nuts that secure the stator housing to the engine-to-generator adapter.

16. Remove the lifting eye bolt (Figure 8-4).

FIGURE 8-3. GENERATOR

1 0. Remove the rotor through-bolt and thread the

special lifting eye (9/16-12) into the end

housing. Refer to Figure 8-3.

or

11. Place a pad protect the scroll. Attach a hoist device to the lifting eye. Tip up the set until completely vertical and resting on the scroll.

Remove the lifting plate when finished.

lA

CAUTION!

the rotor. Do by

this method.

12. Remove the capscrew and two EIT lock washers that hold the ground strap to the drip pan.

13. Remove the vibration-isolator center screws

from the underside of the drip pan, and lift the

drip pan away from the set.

14. Disconnect the lead wires attached to the

starter motor. Loosen the fasteners that mount the starter to the stator housing, and remove the starter.

cushion in front

Careless

not

handling

lift

the entire generator

UFT

of

the engine to

or

other lifting

can damage

the

it is

set

G1175-1

FIGURE 8-4. REMOVAL

17. Carefully lift the stator assembly straight up unti

I it clears the rotor. Set stator assembly to rest

on smooth, clean surface.

lA

CAUTION!

Careless handling can damage the Insulation windings. · against

18. Install the tool shown in Figure 8-5. Use a screwdriver to turn the rotor tool in a clockwise direction until the end breaks loose from crankshaft. Remove capscrew from end of rotor when complete.

Do

the

housing

it bottoms. Install a capscrew in

of

the rotor shaft and tighten until rotor

not

OF

UFTING EYE BOLT

of

the

on

the

brush

as

It

Is

the

lifted

stator

stator windings clear.

• 01 ,

•

C.

D.

ROTOR

10 IN. (254 mm)

/

TOOL

E.

(7/16-14)

02,

F1

and F2 from voltage regulator

VR

1 harness J4

81

and

82

from control printed circuit

board harness Pull the stator leads from the control box. Remove the three stator clamps and

cap screws. Carefully lift the stator straight up until it

clears the stator housing. Set the stator down on a smooth, clean surface.

J1

G1175

FiGURE 8-5. ROTOR TOOL

19. Carefully lift the rotor assembly the engine crankshaft and remove rotor tool.

20.

Uft

the brush wires and remove brush holding

wire from housing. Remove the brush block

mounting screw and carefully remove the

brush block assembly from the stator housing.

off

the end

21. Remove the stator from the stator housing

follows {see Figure 8-6):

A.

Rotate the stator/housing assembly onto a smooth, clean surface, resting on endbearing face (bel! shape up).

B.

Disconnect stator leads:

of

housing facing

* T1, T2, T3, and T 4 from terminal board

TB1

of

as

G1213s

FIGURE 8-6. STATOR/HOUSING DISASSEMBLY

Rotor Bearing Removal

Use a

gear

puller

to

remove the bearing from the ro-

tor

shaft. Attach the

puller arms contact the inner race of the bearing

(Figure 8-7).

lA

CAUTION!

pulled

reused,

The bearing

by

the

It

must

outer

be

gear

race.

pulled

puller so that the

will

be

damaged

If

the bearing Is to

by

the

Inner

race.

gear

be

If

8-10

Ignition

Rotor

Removal/Replacement

FIGURE8-7. ROTOR BEARING REMOVAL

Rotor

Bearing

Replacement

ES-1495/ G-1175

To remove the ignition rotor, simply pry

it off using a

dull-edged pry bar or other implement. To install the ignition rotor, place it over the end of the crankshaft, line the key on the rotor up with the corre-

of

sponding slot in the end

the crankshaft, and tap

the rotor gently into place. Ignition

Module

Removal/Replacement

1. Unscrew the red and black wires extending from the ignition module to the ignition coil. Make certain to note which wire attaches to which terminal on the coil.

2.

Unscrew the two screws holding the ignition

module in place on the generator adapter.

3. When the ignition module is loose, pull the red and black wires through the gap in the generator adapter.

To replace the module, perform the steps listed above in reverse order.

1 . Clean the bearing and shaft mating surfaces.

2.

Apply Loctite #680 adhesive to the shaft mating surface.

3.

Apply Loctite #747 activator to the bearing mating surface.

4. Install the bearing and allow ten minutes curing time before handling the assembly.

Ignition

Components

The ignition rotor and ignition module are located inside the generator. When the stator in its housing

has been removed, the ignition rotor can be removed/replaced on the crankshaft, and the ignition module can be removed/replaced on the generator adapter housing as follows (see Figure 8-8).

IGNITION

ROTOR

ES.1&H.

FIGURE 8-8. IGNITION COMPONENTS

8-11

Generator

1. Install the stator in its housing Figure 8-6):

lA CAUTION! Careless handling

can damage the Insulation on the

windings. Do against the housing as housing,

the

Assembly

A.

Position align with ing. Carefully lower the stator straight down into

and

stator

on

Procedure

as

follows (see

the

stator so the output leads

the

access hole to control hous-

the

stator housing.

of

the

not

brush the windings

It

Is lowered Into

take care

not

to drop

work area outside

or

of

stator stator

stator

housing.

B.

Install

cap screws.

C. Pull

D.

Connect stator leads;

~

T1, T2,

$

01,

VR1

•

81

harness

E.

Rotate

a smooth, clean surface, resting

bell face up).

2. Install the brush block assembly in the housing. Lift brush holding wire in

holds

sembly (see Figure 8-10).

3. Carefully place the rotor assembly

of

the

through-bolt. Tighten

only enough

lA CAUTION! Tightening the

bolt

to the specified torque before the

tor

assembly Is Installed can result shaft misalignment. Follow the mended Installation procedures to any

possibility

4. Carefully plaDe the stator assembly straight down

the

three stator clamps

the

stator leads into control box.

T3

02,

harness

and

82

and T 4

F1

to

terminal board TB1

and F2 to voltage regulator

J4

control printed circuit

J1

the

stator/housing assembly

shape

the brushes

engine crankshaft, and replace

of

the housing (end bearing

the

brush wires and install

the

housing.

off

the

slip rings during as-

on

the rotor through-bolt

to

hold the rotor in place.

rotor

of

shaft misalignment.

over

the

rotor and into position for as-

board

on

stator

The

the

through-

rf!:'com-

avoid

drag

and

onto

the

wire

end

rotor

sts~

rotor

sembly The rotor end-bearing should fit snugly into bearing bore hole.

lA CAUTION I Careless handling

to

the

engine-to-generator adapter.

of

the

stator

can result In damage to the stator windings.

not

Do

the

5.

Install capscrews that secure the engine-to-generator adapter. Tighten cap screws to each locking capscrew head.

brush the

rotor

the

as

It

four nuts, locking washers, and

6. Tighten the rotor through-bolt

torque.

7. Mount

ing using capscrews, lock washers and nuts. Tighten

the

to

starter

the

8. Connect the leads

9. Hold

1 0. Secure

11. Attach

the

drip pan in position derside lator center screws. Note that washers are isolator position). Tighten the

capscrew and that

locking

connection.

the

of

the set,

used

specified torque.

the

ground strap to

the

ground strap is installed between

washers

the

lifting bolt (Figure 8-3) to

stator housing.

12. Attach a hoist

bolt. Carefully tilt the

drip tray.

complete.

stator

windings against

Is lowered Into position.

the

stator housing to

the

specified torque. Note that

washer

specified torque.

two

or

other

Remove

is installed

on

the

generator stator hous-

to

the

starter terminal stud.

to

and

install the vibration-iso-

(large flat washers

the

under

to

the

specified

mount to

proper

center screws

drip tray using a

EIT locking washers. Note

to

ensure a good electrical

the

lifting device to

the

set

back

the

lifting bolt

the

until it rests

the

at

end

the

un-

flat

each

to

the

of

lifting

on

when

13. Connect plug/jack connections P1/J1 and

of

the

P3/J3

the

stall

housing. Tighten

14. Pull

the

wire holding

Make certain

the

slip rings. loosen the brush block mounting screws and adjust. Retighten complete.

control printed circuit board. In-

control panel assembly

the

mounting screws.

brush leads outward and remove

the

bn.Jshes

that

the

brushes

if

the

brushes are not centered,

the

mountina screws when

off

on

the

are

centered

generator

slip rings.

~

the

on

15. Connect the B+ lead minal and the minal. Install the brush block cover and tighten the

cover

16. Connect the leads to the charge resistor, low oil pressure cut-off switch, and ignition coil B+ terminal.

17. Place new intake manifold gaskets on the engine block, and install the carburetor and intake manifold assembly. Tighten the intake manifold screws nect the preheater tube, crankcase breather hose, fuel lines, throttle linkage, and choke heater wires (gasoline units). Refer to Fuel System (Section 6) for detailed assembly procedures.

B-lead

mounting screws.

to

the outboard brush ter-

to the inboard brush ter-

to

the specified torque. Con-

t

11N. (25 mm)

_l

PAINTED OR

MARKED SECTION

OF

""

WIRE

G1174s

18. Install the top cover on the generator set.

19. Install the set in the vehicle and securely fasten all mounting screws and hardware. Connect the fuel, exhaust, and electrical systems in reverse order

Removal section for more information.

20. Fill crankcase with oil of the recommended classification and viscosity.

of

disassembly. Refer

to

the

Set

BRUSHES AND SLIP RINGS

Brush Inspection

Remove the brush block cover and inspect the brushes and brush holder for burns age. If the brushes use a piece to check for excessive brush wear. Insert

through the hole above each brush. Make sure the

wire is resting on the brush and not on part spring. If the painted part the brush is excessively worn and must placed.

of

appear

wire (marked

to be in good condition,

as

of

the wire is not visible,

or

other dam-

shown in Figure 8-9)

the

wire

of

the

be

re-

FIGURE 8-9. CHECKING BRUSH WEAR

Always replace the brush springs when installing new brushes tained.

to

ensure that proper tension is main-

Brush Replacement Procedure

1. Disconnect the negative ( battery terminal.

air

2. Remove the filter element.

3. Remove the brush block cover from the stator

housing.

4. Disconnectthe

board) lead wires from the brush block terminals.

5. Remove the brush block mounting screws and

lift out the brush block.

6. Remove brushes and brush springs from

holder and replace with new parts.

7. Pull and hold both brush lead wires outward

from brush holder. Place brush block assembly into mounting position inside stator housing.

cleaner cover and

F1

(+)(outboard) and F2

-)

battery cable at the

air

cleaner

(-)(in-

8-13

~2~·

8. While continuing to hold the brushes

~~---------------------------------------------

from slip rings, insert from outside stator housing hole, through brush block assembly. Release both brush lead wires.

See

the

brush retainer wire

Figure 8-10.

..----BLOCK

BRUSH

away

Slip

Ring

Inspection

Remove the brush block rings for grooves, pits,

not

in

rings are ished using a black surface exposed brass.

Slip

Ring

good

commutator

is

normal, with

Service

and

or

condition, they

Procedure

Maintenance

cover

and inspect

other

damage. If the slip

stone. A shiny

one

or

two

may

areas

the

be

refin-

brown/

with

slip

RETAINER

...--------

FIGURE

9. Install brush biock mounting tighten only enough to hold brush sembly

1

0.

Lift both brush taining wire compiete!y from

11 . Adjust

are block the

12.

Connect wires board lead.

13. Instal! brush block

14. !nstal!

15.

Connect terminaL

8s10.

BRUSH REPLACEMENT

in position.

!ead

wires

and

brush block

aligned on slip rings, and tighten brush

mounting screws. Do not overtighten,

plastic will crack.

the

voltage regulator

to

brush block terminals;

brush lead, and F2

air

filter element

assembly

with(-)

cover

onto

and

air

{-) battery

WIRE

G-11Ns

screws

remove brush restator

housing.

so

that

and

brush lead

Fi

with (+) out-

inboard brush

stator

cleaner

cable

and

block

to

as-

brushes

housing.

cover.

battery

or

1. Remove

filter.

2. Disconnect

terminals Tie cess

3. Remove

out

lift

4. Insert a 3/8 inch allen wrench into

through-bolt tor tion

ing, continue

need refinishing, follow steps 9 through

the Brush Replacement section.

5. Move

crank

to engine for 3 a rest period between, overheat.

During stone (Onan tooi 420-0259) against rotating slip rings. Remove each cranking period and being removed are smoothed out.

IAWARNINGI Contact with rotating machin-

the

air

cleaner

the

lead

and

then insulate the lead wire ends.

the

lead wires

to

the

the brush

one

full turn. While rotating, inspect

of

slip rings. If

the

Start-Stop switch

the engine. During this step,

engine

to

slip rings.

brush block mounting screws and

block

and

rotate

to

next step. If slip rings

to

6 second cranking periods with

cranking, hold a

and

cover

wires

from the brush

one

side

to

assembly.

the

engine

the

slip rings need refinish-

to

so

the starter will

the

commutator

check

all roughness

and

air

allow

clear

the

and

genera-

START

crank

commutator

stone

that carbon

and

grooves

cleaner

position

ery can cause severe persona/Injury" Keep hands, fingers,

clothing and jewelry clear

while servicing slip rings.

6. Remove insulating material from

age

regulator lead install brush through

14

in the Brush Replacement section.

wires

F1

block

assembly. Follow steps 6

ends

and

F2, and then

block

ac-

rotor

condi-

do

not

14

the

not

after

of

volt-

in

is

GENERATOR TESTING

This section describes test procedures for check-

ing field voltage, rotor, and stator.

Field Voltage Test

To check the field voltage, remove the brush block

DC

cover and connect a

block terminals. Connect the positive lead to the B+ (outboard) terminal and the negative lead to the B(inboard) terminal.

Start the genset and allow the field voltage with no load applied and then with full load applied. Both readings should fall between 18 and 60 volts DC, and be stable If field voltage fluctuates at constant load, refer to Troubleshooting in this section; a possible gover-

or

nor Stop the genset, remove the test leads and replace

the brush block cover when the test is complete.

voltage regulator problem exists.

voltmeter to the brush

it

to stabilize. Measure

at

constant load.

Rotor Test

The rotor may be tested for grounded, open,

shorted windings using an ohmmeter. Figures

and 8-12 show the rotor removed from the generator for testing. However, tor without removing it from the generator. To ob-

tain access to the slip rings, remove the brush block

cover. Lift the brush lead wires and insert a brush

retaining wire from outside stator housing, through

brush block assembly to hold the brushes off the

slip rings during testing.

it is possible to test the ro-

or

8-11

FIGURE 8-11. TESTING ROTOR FOR GROUNDS

Ground

ter to the highest resistance scale. Touch one test

prod to the rotor shaft and hold other test prod to one of the slip rings {Figure A reading less than one megohm indicates that the rotor is grounded. Replace a grounded rotor with a new rotor.

Open

windings, set the ohmmeter for the highest resistance scale. Place test prods

shown in Figure 8-12. The ohmmeter should indicate continuity between slip rings. A high resistance reading indicates a poor connection or an open winding. Check the connection between the slip rings and rotor lead wires. Replace the rotor the rotor winding is open.

To test for shorted windings, set the ohmmeter for the lowest scale. Place the test prods on the slip

rings as shown in Figure 8-12. Resistance reading should be 20.25 to 24.75 ohms

Replace a rotor with shorted windings with a new rotor.

Test: To test for grounds, set the ohmme-

it there. Touch the

Or

Shorted Windings Test: To test for open

on

the slip rings as

at

77° F (25° C).

8-11

}.

if

8-15

Insulate not touch the set housing within the control. Set the ohmmeter to its highest resistance scale, then connect generator housing. Touch the other test prod (see Figure 8-13) to the listed leads individually. A reading less than one megohm indicates a ground. Replace a grounded stator with a

or

position the lead wire ends so they

or

other components

one

test prod

new

stator.

to

do

the

FIGURE 8-12. TESTING ROTOR FOR OPENS

OR SHORTS

Stator Test

The stator windings by using shorted windings requires a digital ohmmeter that can read

Figures 8-13 and from the generator for testing. However, tested without removing

move the control panel

specified lead wires during testing.

Ground Test:

transformer and stator leads

• Stator leads

may

be

tested for grounded

an

to

within 0.01 ohms.

8-14

To

test for grounds, disconnect the

T1

and

T3

or

open

ohmmeter. Testing for

show

it

the stator removed

it

may

be

from the generator. Re-

to obtain access to the

listed below:

from TB1

Open

opens, disconnect the following leads:

Set the ohmmeter to the highest resistance scale. Connect the test prods (see Figure 8-14} generator lead and nuity between lead ends. indicates an open winding. Replace with a new stator.

To test that reads to within tor Connect the test prods (see Figure 8-14) to the leads in pairs The readings for lead pairs should be (plus

or

Shorted Windings Test:

• Stator leads T1, T2, T3 and

• Stator leads

01/02.

B1

and

B2

from A 1

01

and

02

from

ends

in pairs: T1/T2, T3/T4, B1/B2,

The ohmmeter should indicate conti-

A high resistance reading

for

shorted windings, use a digital ohmmeter

0.01 ohms. Disconnect the sta-

leads as specified in

as

specified

or

minus 1 0%):

Leads T1/T2: 0.327 Leads Leads B1/B2: 0.058 ohms Leads

T3/T 01

/02:

4: 0.327

2.089 ohms

the

Open Test section.

in

the

ohms ohms

T4

VR1

an

Open

from

To

test for

TB1

to

the

open stator

Test section.

as

follows

• Stator lead

B1

from A1/P1-1

01

from VR1/J4-11

A reading less than these values indicates shorted windings. Replace a shorted stator with a new stator.

8-16

G1214s

FIGURE 8-13. TESTING STATOR FOR GROUNDS

TEST LEADS:

T1

{f2,

T3ff4, 81/82, AND Q1/Q2

FOR OPEN OR SHORTED

WINDINGS

81/82

FIGURE 8-14. TESTING STATOR FOR

OPENS OR SHORTS

G1214s-1

8-17

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

Section

9.

Engine Block Assembly

GENERAL

The engine block assembly includes:

• Pistons and connecting rods

• Crankshaft

•Camshaft

• Valves and lifters

• Cylinder heads

• Lubrication system

• Timing gears

• Governor mechanism (mechanical)

•Bearings

• Cylinder block

Performing major service on the block assembly re-

be

quires that the genset (see

Set Removal section}. The control, generator,

electronic governor actuator, and all primary engine systems must also access to the block assembly. Refer to the previous sections for disassembly and removal procedures.

removed from the vehicle

be

removed for complete

OIL FILTER AND ADAPTER

Disassembly

1. After allowing the engine

drain valve and drain the crankcase oil.

Procedure

to

cool, open the oil

2. Remove the filter (see Figure 9-1) by turning it

counterclockwise with Onan filter wrench

420-0550.

3. Loosen the two capscrews that secure the

adapter to the engine block and remove the adapter and gasket. The low oil pressure cutoff switch is installed in a threaded hole in the filter adapter.

Assembly To assemble the oil filter and adapter, perform

these steps in reverse order. Install a new adapter

gasket

with the oil holes

installed dry. Coat the threads of

with non-hardening sealer, and tighten to the recommended torque.

Procedure

so that the two small oil holes are aligned

in the block. This gasket should be

each

capscrew

OIL ALTER

LS1175s

FIGURE 9-1. OIL FILTER AND ADAPTER

(BGMSHOWN)

CYLINDER HEADS

Removal/Cleaning

1. Remove the cylinder head capscrews by using a cylinder head.

lA

CAUTION

removed while hot. Also,

parts

the engine has heads.

may

2. After removing the heads, clean out all carbon

deposits. Be careful not to damage the outer sealing edges where the gaskets fit. The heads are made

damaged by careless handling.

Assembly

Procedure

or

1/2 inch socket wrench. Lift off the

I The heads

cause

cooled

may

warp

If

they

contact

burns

of

(BGM)

to skin. Walt

before removing the

aluminum, and may be

with

until

1. Use new head gaskets, and clean both the

heads and the cylinder block thoroughly where the gaskets rest.

2. Place the heads in position, and follow the

head torque tightening sequence shown in Figure

lbs {7

all bolts fied torque (see

9-2. Start by tightening all bolts to 5 ft-

N•m),

then

10

fHbs

(14

N•m),

or

stud nuts are tightened to the speci-

Torque Specification section).

etc., until

nuts

are hot

9-1

COMPRESS!~./

WASHERS

(llj

II NUTS

HEAD

HEAT

TREATED

LEFT* RIGHT*

*

AS

VIEWED

FIGURE

Assembly

1 . Use new head gaskets, and clean both the

heads and the cylinder block thoroughly where

9~2.

TIGHTENING SEQUENCE

Procedure (NHM)

FROM

FRONT OF ENGINE

BGM CYLINDER HEAD

C1002s

the gaskets rest.

2.

Place a head gasket on the cylinder head and align the stud holes in the gasket with the stud holes in the cylinder head. While holding the gasket against the cylinder head, carefully install the cylinder head on the engine. Do not attempt out the cylinder head behind

may tear.

to

slide the gasket over the studs with-

it or the gasket

3. install a flat washer, two compression wash-

of

ers, and nut on each

Figure 9-3 for correct sequence). When properly installed, only the outside edges compression washers will each other. Install a flat washer and nut on

of

each

the four bottom studs.

the top six studs (see

of

be

in contact with

the

-~~-

6 LONG 4 SHORT

STUDS/HEAD STUDS/HEAD

FIGURE 9-3. NHM CYLINDER HEAD WITH

COMPRESSION WASHERS

4. Follow the head torque tightening sequence shown in Figure 9-4 for the NHM. Start

ening all bolts to

5 ft-lbs (7 N•m), then 10 ft-lbs

(14 N•m), etc., until all bolts

tightened to the specified torque (see

........._HEAD

GASKET

M191h

by

or

stud nuts are

Torque

tight-

Specification section). Recheck all nuts for

correct torque.

lA CAUTION I

compression washers

Too

much torque

and

will

could

flatten the

result In

engine damage.

5. Recheck torque before engine has run a total

of

50 hours.

lA CAUTION! Do

when they are hot. Warpage The gasket surface

before removal.

10~

F,

the gasket

difficult

block

to remove from the surface

and

not

cylinder

torque

or

remove heads

may

must

At

will

be

below

temperatures above

become

gummy

head.

occur.

10~

F

and

of

the

·~

..

9-2

LEFT*

RIGHT*

* AS VIEWED FROM FRONT

OF

FIGURE 9-4. NHM CYLINDER HEAD

TIGHTENING SEQUENCE

BGM

VALVE

INSERT

NHM

GUIDE

ENGINE

CLEARANCE

M1871c

VT10:U.

VALVE

VALVE STEM

SEALONTAKE

ONLY)

FIGURE 9-5. VALVE SYSTEM

9-3

VT1005s

~ROTAIDR

(EXHAUST ONLY)

(NOTE:

ROTATORS ARE PRESENT

BOTH INTAKE AND

ON

LPG NHM, VALVE

EXHAUSl)

ON

VALVE SYSTEM

A properly functioning valve system is essential for the engine to perform well. Onan gensets use an

as

L-head valve design,

valve system may be accessed by removing the cylinder heads and valve covers on top gine.

der

A valve spring compressor must

remove the va!ves (see Figure 9-6) from the cylin-

block. Use the procedures described below to

inspect

and service the valve system.

shown in Figure 9-5. The

of

the en-

be

used to

VT1017s

FIGURE 9-7.

Burning and pitting are caused by the valve failing

to seat tightly. This condition is often caused by

hard carbon particles

caused by

clearance, valve warpage, Warping occurs chiefly

it is exposed sults from warping, valve whose head is not in line with the stem and guide. If a valve face is burned stem

weak

valve springs, insufficient tappet

to

intense heat. Out-of-round

is worn, install a

VALVE

on

the seat. It may also

in

the

when

the

new

FACE

and

misalignment.

upper

seat is pounded by a

or

valve.

be

stem, because

wear

re-

warped,

or

the

FIGURE 9-6.

VALVE

SPRING COMPRESSOR

Valve Inspection Procedure

Valve Face: Check the valve face for evidence

burning, warping, out-of-round, and carbon deposits {see Figure 9-7).

of

air

Excess clearance in the intake guide admits

the

oil into buretion, increasing oil consumption, and making heavy carbon deposits. Carbon prevents heat dissipation. Clean metal is carbon insulates and retains heat. This increases combustion chamber temperatures, causing warp-

and

ing valve stems, causing them

Valve Stem Seal: A valve stem seal

intake valve guides.

each time

Stems

guides gauge clearance with ance

by 0.002 inch (0.05 mm), replace either the

or

valve

if

seat newly installed guide.

combustion chamber, upsetting car-

a

good

heat conductor, but

burning. Unburned carbon residue gums

to stick in the guide.

is

used on the

This

seal

must

be replaced

the

valve

is

removed.

and

Guides:

for

wear,

as

to

measure

the

guide

necessary,

or

both,

Check

shown

the

stem exceeds

to

in

valve guide. When valve

as

necessary. Regrind the

make

valve stems and

Figure 9-8. Use a hole

the

original clear-

it concentric with the

and

FIGURE 9-8. VALVE STEM AND

VALVE GUIDE INSPECTION

VT1021s

FIGURE 9-9. VALVE INTERFERENCE ANGLE

VT1020s

The valves must not be hand lapped, because the sharp contact between the valve and the seat will be destroyed. This is especially important where chrome cobalt faced valves and seats are used.

Valve faces must be finished to 44 degrees, in a machine.

Springs: Check the valve springs for cracks, worn

If

ends, distortion and tension. worn, check the valve spring retainer for wear. Check for spring distortion by placing each spring on

a flat surface next to a square. Measure the height of the spring and rotate it against the square edge to measure its distortion. Check the spring tension at the installed height in both the valve open and closed positions, using a valve spring tester.

Replace any valve spring that is weak, cracked,

worn, or distorted.

Reconditioning Valves and Valve Seats

The interference angle method of valve seating is used on all B and N series genset engines. This

method uses different seat and face angles, and line contact is made between the valve face and seat.

The valve face angle is angle is 45 degrees. This 1-degree interference angle results in a sharp seating surface between the valve and the top of the valve seat (see Figure 9-9).

44

the spring ends are

degrees. The valve seat

Each valve must have a minimum of 1/32 inch (0.8

9-1

mm) margin (see Figure margin than this, retain this heat during the compression stroke, and pre-ignite the mixture, causing loss of power and economy. This valve is also susceptible to warping and breakage.

it will heat up excessively. It will

0). If the valve has less

KNIFE EDGE

\ 7

l (

GOOD MARGIN

\ )

I(

FIGURE 9-10. VALVE MARGIN

Not all valves can be reconditioned. A badly

warped valve must be replaced, because the

amount of grinding required to make it seat correctly removes its margin. To make a valve gas-

tight, remove all pitting from the valve face and

1 (

_!_

T

0.301NCH

MINIMUM (0.8

111184a

mm)

9-5

seat. Deeply pitted because grinding removes the margin.

or

cut valves must be replaced,

A suggested method ure

9-11.

of

installation

is

shown in Fig-

Grind valve seats with a 45-degree stone. The width

of

the

seat band should be 1/32 inch

(0.

79

to

inch be sure

Place each valve

valve for a tight seat. Make several marks at regu-

lar intervals across the valve face using machinist's bluing. Observe the valve is rotated part The valve seat should contact the valve face evenly at all points. The line of contact should be center

Valve

Worn valve stem guides can

side the valve chamber. the tapered valve guides must face toward the

valve head.

Tappets

ber, after the valve assemblies are removed first.

Valve

of

Guides

Guide

1.2 mm) wide. Grind only enough to

of

proper valve seating.

in its proper location. Check each

if

the marks rub off uniformly when

of

a turn against the seat.

the valve face.

be

replaced from in-

The

smaller diameter

are also replaceable from the valve cham-

Removal

Procedure

to

3/64

at

the

of

ROD

5/16-18 HEX. NUT (2 REQUIRED)

5/161N. FLATWASHER

(2 REQUIRED}

~~®

"""

1 . Before removing the valve guides, use

tric drill with a wire brush other foreign material from the top surface

the guides. Failure to damage

2.

Drive the guides out with a valve forming this procedure.

lA CAUTION I Driving

to

the guide bores.

guide driver. Wear goggles while per-

out

damage the tappet bores.

the

to

remove carbon and

do

this may result in

hammer

old

valve guides can

Be

careful

an

and a

not

strike the bores with the driver.

Valve

Guide

Installation

Procedure

1. Run a small polishing rod with crocus cloth

through the vaive guide holes, to clean out car-

bon and

2. Coat the outer edge

other foreign materials.

of

each new guide with

it in

rests against the cylinder

elec-

of

to

oit

FIGURE

Valve

9~11.

Seats

(178mm)

7iN.

2-3/8"~

f

5/8 iN. (16

VALVE GUIDE

mm)

/4

5/16-18 THREADED

ROD

~NSTALLATION