Generac 86640 User Manual

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Manual Part No. 86640

SERVICE

Manual

NP and IM Series

RECREATIONAL

VEHICLE AND

INDUSTRIAL MOBILE

AC GENERATORS

Liquid-Cooled 1.2 Liter Gas Engine Models

CORPORATION

♦ P. O. Box 8 ♦ Phone: (414) 544-4811

♦Waukesha, Wisconsin 53187

♦ FAX: (414) 544-4851

Original laaua (02/28/93)

Printed In U.SJt.

Foreword

PURPOSE OF MANUAL:

This Service Manual has been written and published by Generac Corporation to aid our Dealers" mechanics and company service personnel In the maintenance, servicing, troubleshooting and repair of the products described herein. All information, illustrations and specifications are based on the latest product Information available at the time of publication.

Proper service and repair Is important to the safe, economical and reliable operation of all recreational vehicle and Industrial mobile generators. Troubleshooting, testing and servicing procedures recommended by Generac and described In this manual are effective methods of performing such operations. Some of these operations or procedures may require the use of specialized equipment Such equipment should be used when and as recommended.

Generac could not possibly know of and advise the generator service trade of all conceivable procedures by which a service or repair might be performed or of the possible hazards and/or results of each method. We have not undertaken any such wide evaluation. Therefore, anyone who uses a service procedure, method or tool not recommended by Generac must first completely satisfy himself that neither his nor the product’s safety will be endangered by the procedure or method selected.

USER’S RESPONSIBILITY:

It Is assumed that service personnel are familiar with the servicing procedures of these products or like or similar products manufactured and marketed by Generac. It Is further assumed that such personnel have been trained In the recommended servicing procedures for these products; and that such training Includes the use of mechanic’s common hand tools, special Generac tools, and tools from other suppliers.

■-!

SAFETY:

When working on this product, it must be remembered that the generator AC electrical system produces high and dangerous voltages that can cause severe electrical shock. Contact with high voltage terminals, bare wires, etc., can result In dangerous and even fatal Injury.

To prevent accidental engine cranking and startup, always disconnect battery cables before working on or around the generator.

Cover all openings Into the engine-generator, to prevent entry of foreign materials. Such materials could enter the engine cylinders and cause extensive damage when the engine Is started.

It Is Important to note that the manual contains various DANGER, CAUTION and NOTE blocks. These should be read carefully In order to minimize the risk of personal Injury or to prevent methods or practices from being used which could damage equipment or render It unsafe.

FASTENERS:

Replacement fasteners must have the same measurements and strength as the fasteneres they will replace. Numbers on the heads of metric bolts and on surfaces of metric nuts indicate their strength. Customary nuts do not have strength markings. Mismatched or incorrect fasteners can cause damage, equipment malfunction or possible Injury.

REPLACEMENT PARTS:

Many parts used on recreational vehicle generators and engines are designed and manufactured to comply with rules and regulations established by the Recreational Vehicle Industry Association (RVIA), American National Standards Institute (ANSI), and the National Fire Protection Association (NFPA). Strict compliance with such rules and regulations help to minimize the risk of fire or an explosion. Use of any replacement part that does not comply with such rules and regulations could result in fire or explosion hazard and should be avoided.

SERVICE

MANUAL

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

TABLE OF CONTENTS

PART

1 2 ENGINE MECHANICAL 3 ENGINE LUBRICATION SYSTEM 4 5 GASOLINE FUEL SYSTEM 6 GASEOUS FUEL SYSTEM 7 ENGINE SPEED CONTROL SYSTEM 8

9 ENGINE DC ELECTRICAL SYSTEM 10

11 SPECIFICATIONS & ELECTRICAL DATA

ENGINE COOLING SYSTEM

ENGINE IGNITION SYSTEM

OPTIONS AND ACCESSORIES

TtTLE

THE AC GENERATOR

MOBILE

GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Models

Part 1

THE

SECTION

1.1

1.2

1.3

1.4

1.5

1.6

TITLE

How Generators Produce Electricity

Major Generator Components

Insulation Resistance Tests

Introduction to Troubleshooting

Troubleshooting Flow Chart

Troubleshooting Test Procedure

GENERATOR

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERATORS

Liquid Cooled 1.2 Liter

Gas Engine Models

Manual Familiarization

This Service Manual has baan dividad Into alevant (11) PARTS.' Each PART consists of ons or mors SECTIONS. Each SECTION Is divided Into two or more SUBSECTIONS. Each SUBSECTION may be made up of one or more PARAGRAPHS.

A DIVIDER page separates each PART of the Manual. The DIVIDER page provides a TABLE OF CONTENTS which lists the SECTIONS that may be found In that PART.

Page numbers at the bottom of each page Identify the PART number, SECTION number, and the specific page. For example. Page 2.3-4 Indicates PART 2, SECTION 2 J, and Page 4 of that SECTION. This type of numbering system allows Individual SEC TIONS to be kept current without affecting page numbers In the entire Manual.

Section 1.1- HOW GENERATORS PRODUCE ELECTRICITY

It has long been №own that a relationship exists between

Magnetic Induction

magnetism and electricity. Revolving field AC generators depend on this relationship for their operation. If generator problems are to be properly diagnosed, the service techriician must understand this relationship. Magnetism can be used to create an electrical voltage in a conductor. Conversely, elec trical current flow through a conductor will create a magnetic field around that conductor.

See Figure 1, below. When a conductor is moved through a magnetic field, an electromotive force (EMF or voltage) is induced Into the conductor. Movement of the magnetic field so that It cuts across the conductor will also create a voltage In the conductor. If the ends of the conductor are connected to form a complete circuit, current will flow through the conductor. The direction in which the current flows depends on the polarity of the magnetic field and the direction in which the magnetic field (or conductor) is moved. The amount of voltage Induced into the conductor depends on the strength or concentration of the magnetic field, i.e., the stronger the magnetic field, the higher the induced voltage.

See Rgure 2. When current flows through a conductor, a magnetic field is created around that conductor. The strength of the magnetic field depends on (a) the amount of current flow, (b) the number of turns or loops in the conductor. The polarity of the magnetic field depends on the direction of current flow through the wire. The following facts should be evident:

□ If current flow through a conductor can be regulated, the

strength of the magnetic field around the conductor can be regulated.

D If the strength of a magnetic field can be regulated, the

amount of voltage induced into a conductor by such a

magnetic field can also be regulated.

Figure 3 represents a simple AC generator, in which the

A Simple AC Generator

rotating magnetic field (Rotor) Is a permanent magnet. As the

magnet rotates, its magnetic field cuts across a stationary coil of wires called a STATOR. When the magnet’s North mag netic pole moves past the stator windings, current moves through the wire in one direction. As the South magnetic pole of the magnet passes the stator wires, current reverses itself and moves through the stator in the opposite direction.

in the simple generator shown, the strength of the mag net is fixed. That \ the magnetic field strength cannot be changed since a permanent magnet is used. Because the magnetic field strength is fixed, the voltage induced into the stator coil is constant

If some method of regulating the magnetic field strength of the magnetic could be found, the voltage induced into the stator coil could be regulated as well.

Figure 3. A Simple Revolving Field Generator

Paga 1.1-1

A More Sophisticated Generator

Figure 4 Is a diagram of a more sophisticated generator.

A regulated direct current (DC) is delivered to the rotating magnet (Rotor), via CARBON BRUSHES and SUP RINGS. This creates a regulated magnetic field around the Rotor which cuts across the stationary Stator windings to Induce a

regulated voltage into those windings. When the Stator circuit is corfipleted by connecting a load, current will flow through

the Stator windings to the load.

Rgure 5, below, Is an operating diagram of a typical AC

A Typical AC Generator

generator. Operation of this typical generator may be briefly

described as follows:

D The ROTOR is attached to the engine’s power takeoff

(PTO) shaft and turns at the same speed as the engine.

D As the ROTOR turns, its magnetic field cuts across the

stationary coils of a STATOR EXCITATION WINDING and dual STATOR AC POWER WINDINGS. A voltage is induced into these stationary widings.

□ Unregulated alternating current (AC) is delivered from

the STATOR EXCITATION WINDING to the VOLTAGE

REGULATOR, via an EXCITATION CIRCUIT BREAKER.

n "Sensing" leads deliver a signal of ACTUAL AC POWER

WINDING voltage to the VOLTAGE REGULATOR.

n The VOLTAGE REGULATOR electronically compares

the ACTUAL AC POWER WINDING voltage to a preset

REFERENCE VOLTAGE and changes №e STATOR EXCITATION WINDING output to direct current (DC).

□ If ACTUAL POWER WINDING voltage Is less than the

REGULATOR’S preset REFERENCE voltage, REGU LATOR action will increase direct current flow to the

ROTOR windings. The ROTOR magnetic field strength will then increase and the voltage induced into the STA TOR AC POWER WINDINGS will then increase.

□ When ACTUAL POWER WINDING voltage is greater

than the REGULATOR’S preset REFERENCE voltage,

direct current flow to the ROTOR will be decreased by

REGULATOR action to reduce ROTOR magnetic field

strength.

-S-

Rgure 5. Operating Diagram of a Typical AC Generator

ITEM

i 2 3

4 5 6 7 SLIP RINGS

DESCRIPTION

RÓTOF1

STATOR POWER WINDING STATOR EXCITATION WINDING

FIELD BOOST ENGINE BRUSHES

VOLTAGE REGULATOR SENSING LEADS THERMAL PROTECTOR THERMAL PROTECTOR BYPASS

EXCITATION CIRCUIT BREAKER

ELECTRICAL LOAD

MAGNETIC FIELD

Page 1.1-2

□ The VOLTAGE REGULATOR will continue to increase

or decrease direct current flow to the ROTOR, In an attempt to maintain STATOR AC POWER WINDING voltage at the same value as the REGULATOR’S preset

REFERENCE voltage.

□ When the STATOR AC POWER WINDING circuit is

completed by connecting a load to the winding's AC output leads, current will flow through the windings and to the load.

Rotor Residual Magnetism

The Rotor may be considered a permanent magnet since

some residual magnetism is always normally present In the

Rotor windings. As a general rule. Rotor residual magnetism atone (without regulated excitation current and without field boost current) will produce a STATOR AC POWER WINDING output of approximately 2 to 7 volts.

Field Boost

When the engine Is being cranked, direct current is delivered to the Rotor windings from a source other than the Stator excitation windings and Voltage Regulator. This direct current, in effect, Hashes the field" every time the engine is cranked. By applying field boost current to the Rotor during cranking, an early "pickup" voltage Is induced into the Stator windings to turn the Regulator on sooner and provide AC output more quickly.

Failure of the field boost circuit rrray or may not result In toss or dropout of AC power winding output voltage, depend ing on the characteristics of the Individual generator. The following general rules apply:

D If Rotor residual magnetism atone (without field boost) is

sufficient to turn the Voltage Regulator on and provide

the required pickup voltage, the generator will operate

normally with normal AC output voltage.

G If Rotor residual magnetism atone (without field boost) Is

NOT sufficient to turn the Regulator on and provide the

needed pickup voltage, generator AC output voltage will

not build and will be commensurate with Rotor residual

magnetism (about 2 to 7 volts AC). G If regulated excitation current to the Rotor is lost. Stator

AC power winding output voltage will drop to a value that

is commensurate with Rotor residual magnetism (2 to 7

volts AC). The magnetic field strength created by field

boost current cannot be considered since it is available

only while cranking.

Figure 6. Field Boost Circuit (Gasoline Fuel System)

STARTER CONTACTOR

-TO STARTER

11 CHOKE

* MODULE

° 1 FROM

TO ROTOR •

Figure 7. Field Boost Circuit (LP Gas Fuel System)

BATTERY

-Q)

ENGINE CONTROL CIRCUIT BOARD

La/v-J

RESISTOR 47 OHM. 2 WATT

TO IGNITION COIL

9 RESISTOR ^9°^

-----

W\ T-

too OHM 200V.

1 WATT 1 WATT

W-

ENGINE CONTROL CIRCUIT BOARD

DIODE

AMPY 1 AMf

TO ROTOR

UNITS WITH GASOLINE FUEL SYSTEM;

See Figure 6. Units equipped with a gasoline fuel system

use a choke module (CM) which closes and opens a choke solenoid (CS) during engine cranking to open and close the carburetor choke.

UNITS WITH LP GAS FUEL SYSTEM:

Units equipped with a gaseous fuel system do not require a carburetor choke and do not have a choke module. The field boost circuit for such units Is shown in Rgure 7. While cranking, battery voltage is delivered to Terminal No. 8 of an

engine control circuit board, to Wire No. 9, a field boost

assembly. Wire No. 4, and to the Rotor via brushes and slip

rings.

The field boost assembly, shown In Figure 8, consists of

a 100 ohm, 1 watt resistor (1^) and a 200 volt, 1 amp diode

(D2). The diode ensures that current will flow in one direction

only in the circuit. The resistor reduces the battery voltage

(12 volts DC) to approximately 9-10 volts DC.

GENERAL:

The excitation system is shown schematically in Figure

9. During operation, unregulated AC current from the Stator excitation winding is delivered to the Voltage Regulator via a Thermal Protector, Wires 2 and 6, an excitation circuit breaker (CB4), and Wires 2A and 6. The Voltage Regulator rectifies and regulates the current flow, which is then deliv ered to the Rotor windings via Wires 4 and 1, and the brushes and slip rings. Major components of the excitation system include the following;

D Stator Excitation (DPE) Winding, n Thermal Protector (TP). D Excitation Circuit Breaker (CB4).

D AC Voltage Regulator.

D Brushes and Slip Rings, n Rotor Assembly.

Excitation System

THERMAL PROTECTOR:

A Thermal Protector (tP) is physically imbedded in the wire windings of the Stator assembly and electrically con nected in series with the excitation winding AC output leads

to the Voltage Regulator. The device is a normally-closed (N.

C.), temperature sensitive switch. Should Stator tempera tures exceed a preset level, the switch contacts will open. The switch is self-resetting. That is, its contacts will close when Stator temperatures decrease below a safe, preset level.

If the switch contacts open, excitation winding output to the Regulator will terminate and the Regulator will shut down. Generator AC output voltage will then drop to a value com mensurate with the Rotor’s residual magnetism (about 2 to 7 volts AC).

The thermal protector is NOT accessible and cannot be

replaced. If it has failed open, it can be bypassed by connect ing excitation lead No. 2 to a bypass lead No. 5. Once the switch has been bypassed, overtemperature protection is no longer available.

EXCITATION CIRCUIT BREAKER (CB4):

If this circuit breaker has failed open, the results will be the same as a Thermal protector that has failed open. That is, generator AC output will drop to about 2-7 volts AC

(residual).

Page 1.1-4

AC VOLTAGE REGULATOR:

See Figure 12. Sensing leads deliver ACTUAL AC power winding voltage signals to me Regulator via Leads 11 and 22 and Regulator terminals 5 and 6. The Regulator electronically compares this ACTUAL signal to a preset REFERENCE voltage, then acts to maintain an ACTUAL voltage that Is equal to the REFERENCE voltage.

If ACTUAL voltage is less than the preset REFERENCE voltage, the Reoulator will increase excitation current flow to the Rotor. The Rotor's magnetic field will then strengthen and the AC output voltage will increase.

If ACTUAL voltage is greater than preset REFERENCE voltage. Regulator action will decrease excitation current flow to the Rotor. The Rotor’s magnetic field strength will drop and ACTUAL voltage will decrease.

The typical AC Voltage Regulator shown in Figure 12 has a single amustable potentiometer, used to establish the de sired REFERENCE voltage.

BRUSHES AND SLIP RINGS:

The Brushes and Slip Rings (Figure 13) allow excitation current flow to be transmitted rrom a stationary member to a

rotating member. The Slip Rings are actually a part of the Rotor assembly. As a general rule, the positive slip ring is the one nearest the Rotor bearing. Wire No. 4 is the positive

brush lead; Wire No. 1 is the negative baish lead.

NOTE: At the time thie Manual was written, all NP/IM Series generators were equipped with the dual, 1-phasa stator configuration. Some other possible stator config urations will be mentioned here to cover future possibil ities.

Stator AC Power Connection Systems

GENERAL:

Any one of several different connection systems are

used on NP and IM Series generators. Theses are(a) dual

1-phase, (b) 3-phase Delta, and (c) 3-phase Wye-Connected

systems.

DUAL WINDING. 1-PHASE SYSTEM:

Figure 14 is a schematic representation of dual 1-phase

Stator AC power windings. Each Stator winding can supply a

120 volts AC output. When the two windings are connected In series to form a 3-wire connection system, a 240 volts AC output results.

Connected for Dual Voltage Output Some dual wind

ing systems may have been connected to provide a dual voltage output (120 and/or 240 volts AC). See Figure 15.

Stator AC output leads 11 (T1) and 44 (T3) form the two hot

leads. The Junction of Stator leads 22 and 33 form the

"Neutral’ line (T2).

Connected for Single Voltage Output: If desired, the Stator AC ou^ut leads can be reconnected for single voltage output only (Figure 16). When this Is done, a jumper wire must be connected between the two main circuit breakers (CB1 and CB2).

Page 1.1-5

stator AC Power Connection Systems (Continued)

3-PHASE DELTA STATOR SYSTEM:

Figure 17 is a schematic representation of a 3-phase Delta Stator configuration. Phase rotation is L1-L2-L3. The “Neutral" line is designated “LO".

3-PH^ASE WYE-CONNECTED SYSTEM:

See Figure 18. This type of Stator consists of six (6) coils and twelve (12) leads coming out of the Stator. The twelve leads are reconnectable to supply several different voltages.

Page 1.1-6

Section 1.2- MAJOR GENERATOR COMPONENTS

This section will discuss generator disassembly, Inspec

tion of components, and reassembly. See Figure 21 on Page

1.2-2.

Generator Disassembly

To disassemble the generator, proceed as follows. See

Figure 21.

1. Remove the four capscrews, lockwashers and flatwashers (Items 22, 23 and 24) that retain the REAR BEARING CAR RIER PLATE (Item 20) to the REAR BEARING CARRIER (Item 15). Remove the REAR BEARING CARRIER PLATE (Item 20).

2. Remove the Rear Bearing Carrier GASKET (Item 18).

3. Disconnect wires from BRUSH HOLDERS (Item 16).

4. Remove SCREWS (Item 17) that retain the BRUSH HOLD ERS (Item 16) to the Rear Bearing CARRIER (Item 15). Remove the BRUSH HOLDERS (Item 16).

5. Remove hardware that retains the Rear Bearing CARRIER (Item 15) to the generator mounting base.

6. Remove the four long CAPSCREWS (Item 21), along with

four LOCKWASHERS (Item 10).

7. A REAR BEARING CARRIER PULLER tool Is available.

See Figure 19. To order the tool, specify Part No. 74078.

a. Retain the PULLER TOOL to the Rear Bearing CAR RIER (Item 15) using the same M6-1.00 x 8mm screws

ltem 22) that were used to retain the Rear Bearing Carrier »LATE (Item 20).

b. Turn the center bolt on the PULLER TOOL (Figure 19) clockwise until the Rear Bearing CARRIER (Item 15) is free of the Rotor bearing.

c. Completely remove the Rear Bearing CARRIER (Item

' 15).

8. Free the STATOR ASSEMBLY (Item 14) from the BLOWER HOUSING (Item 2). Completely remove the STA TOR ASSEMBLY (Item 14).

Introduction

12. Remove the ROTOR ASSEMBLY (Kern 1) with the FAN

& RING GEAR (Item 25) attached.

13. Remove CAPSCREWS and LOCKWASHERS (Items 34 and 36) that retain the FLEX PLATE (Item 28) to the engine flywheel. Remove the FLEX PLATE (Item 28).

14. If the FAN & RING GEAR is to be removed from the

ROTOR (Item 1), proceed as follows:

a. Remove CAPSCREW and LOCKWASHER (Items 30 and 31) that retain the FAN & RING GEAR to the ROTOR. b. Remove the SPACER (Item 27).

c. Remove the FAN & RING GEAR (Item 25) from the ROTOR.

NOTE: The FAN & RING GEAR ASSEMBLY (Item 25) Is retained to the ROTOR shaft by a KEY (Item 26).

Inspection of Major Components

REAR BEARING CARRIER Pj^TE:

Air slots in the Rear Bearing Carrier Plate allow cooling air to be drawn into the generator by fan action during operation. These air slots must be kept open and unob structed. Clean the plate and check for cracks, obvious damage. Replace the Plate, If necessary.

BRUSHES:

Inspect both Brush Holders and their Brushes. Look for cracks, chipping, excessive wear. Replace any damaged Brush Holder. Brushes should be replaced as a complete set. Inspect Boish Leads No. 1 and 4, replace any damaged or defective Brush Lead.

Figure 20. Brush Holders, Brushes and Leads

9. Remove the hardware that retains the STARTER (Item 40) to the ENGINE PLATE (Item 29). Remove the STARTER.

10. Remove all fasteners that retain the BLOWER HOUSING (Item 2). Remove the BLOWER HOUSING.

11. Remove CAPSCREWS (Item 33) that retain the FLEX PLATE (Item 28) to the FAN & RING GEAR (Item 25).

BRUSH WITH RED LEAD CLOSEST

BRUSH

TO ROTOR BEARING

HOLDER

SCREW

n-rf

REAR BEARING CARRIER:

The Rear Bearing Carrier is an aluminum casting. Clean the casting and blow dry with compressed air. Inspect care fully for cracks, damage. An insert is pressed into the bearing carrier center bore, to accept the Rotor bearing. Use an Inside micrometer to check the diameter of the Insert. Replace the Rear Bearing Carrier If its insert’s inside diameter (I.D.) is not within the following limits:

2.384-2.386 Inches (71.996-72.012mm)

Page 1.2-1

Figure 21. Exploded View of AC Generator Assembly

ITEM 1 1 2 1 3 4 5

5 5 6

8 9 10 9 11 3 12 2 13*

14 1

15 16 2 17 18

19 20 21 22 23 24 4 25 26

* User

QTY

i to mount the generator control panel. ** Part of Engine Governor system.. See Part 7.

DESCRIPTION ITEM QTY DESCRIPTION Rotor Assembly 27 Blower Housing

4 1 1 2

4 1 4

1 1 1

4 4 8

1 1

Air Outlet Screen 29 1

Pan Head Machine Screw 30 1

Lockwasher

Flatwasher 32 Hex Head Capscrew 33 4 Hex Head Capscrew

Flatwasher

Lockwasher 36

Hex Nut

Dowel Sleeve

Vibration Dampener 39 3

Stator Assembly

Rear Bearing Carrier 41 1

Brush Holder

Hex Head Screw 43 1

Rear Bearing Carrier Gasket

Flame Arrestor

Rear Bearing Carrier Plate

Hex Head Capscrew Hex Head Capscrew

Lockwasher 51

Flatwasher

Rywheel & Ring Gear Assembly

3/8* square x 1" Key

28 1

34 35 7

37 1 38 1

40 42 44

45 46

47- 1

50 1 52

1 2 1

1 1

Magnetic Pickup Assembly

Spacer

Flex Plate

Engine Plate

Hex Head Capscrew

Lockwasher Hex Head Capscrew Hex Head Capscrew

Lockwasher

Hex Nut Hex Head Capscrew Hex Head Capscrew

Hex Nut

Flatwasher

Starter Motor

Starter Adapter

Hex Head Capscrew

Fan Access Cover

Ignition Coll

Ignition Coll Bracket

Screw

Rubber Grommet

Hex Head Capscrew

Hex Nut

Page 1.2-2

STATOR ASSEMBLY;

Clean the Stator can exterior surfaces with a soft brush or cloth. Use clean, dry, low pressure air (25 psi maximum) to clean the Stator.

Use an ohmmeter or a volt-ohm-milliammeter (VOM) to test the resistance of Stator AC power windings and excita tion (DPE) windings. See Section 1.6.

Use an insulation resistance tester (megohmmeter or

hi-pot tester) to check the condition of stator insulation (see Section 1.3). If stator insulation is breaking down, dry the

stator by blowing warm, dry air across it for several hours. Do

NOT exceed 185* F. (85‘ C.). If insulation resistance Is still low after drying, replace the stator assembly.

BLOWER HOUSING:

Clean the cast aluminum blower housing. Inspect the

housing carefully for cracks, damage.

FLEX PLATE;

The flex plate is of 16 gauge steel. Clean the flex plate,

then inspect it carefully for cracks, damage, wear. Check all

holes for elongation and wear.

ROTOR ASSEMBLY;

Use clean, dry, low pressure air (25 psI maximum) to clean the rotor. Use a volt-ohm-mllliammeter ^OM) to check the resistance of Rotor windings (Section 1.6).

Check the Rotor bearing for binding, seizing, roughness. The bearing is pre-lubricated and sealed; It requires no addi tional lubrication for the life of the bearing. If the bearing Is defective, replace the Rotor assembly.

Check the keyway in the Rotor’s tapered shaft for wear or damage. Also, inspect the drive key.

Inspect the slip rings. A dull or tarnished appearance indicates oxidation on the slip ring surface. If necessary, clean the slip rings with fine sandpaper. DO NOT USE ANY

METALLIC GRIT TO CLEAN SLIP RINGS.

Use an Insulation resistance tester (megohmmeter or hi-pot tester) to check fhe Rotor for Insulation breakdown. If insulation resistance Is low, dry the Rotor with heated, dry air.

DO NOT EXCEED 165* F. (85 C.). If the insulation resistance is still low after drying, replace the Rotor assembly.

FAN AND RING GEAR ASSEMBLY:

During factory assembly, the ring gear is heated to 400* F. and the blower fan is installed. The entire assembly is then statically balanced. If the fan and ring gear must be replaced, replace It as an assembly.

Page 1.2-3

Section 1.3- INSULATION RESISTANCE TESTS

Effects of Moisture and Dirt

The insulation in RV and IM generators is moisture resistant. However, prolonged exposure to moisture will grad ually decrease the resistance of Stator and Rotor insulation. If moisture is allowed to remain in contact with generator

windings, some of the moisture will be retained in cracks and voids of the iunsulation. This will result in a reduced insulation

resistance and, eventually, the unit’s AC output will be af

fected.

Dirt can make the problem worse since it tends to hold

the moisture Into contact with the windings.

Salt, as from sea air, can also worsen the problem since salt absorbs moisture from the air. When salt and moisture combine, they make a good electrical conductor.

Because of the detrimental effects of dirt and moisture,

the generator should be kept as clean and dry as possible. Stator and Rotor windings should be tested periodically with an insulation resistance tester such as a megohmmeter or hi-pot tester. If the insulation resistance is excessively low, drying may be required to remove moisture. After drying, a second test of the Insulation should be performed. If resis tance Is still low after drying, replacement of the defective windings may be necessary.

Insulation Resistance Testers

Figure 22 shows Just one type of hi-pot tester. The tester

shown is one of many brands that are commercially available. It has a "Breakdown^ lamp which will glow to Indicate insula

tion breakdown during the test.

Normally, the resistance of insulation is measured on the

order of millions of ohms, it can be measured w'rth a device called a 'megger', which is a megohm meter (meg is for million) and a power supply. The power supply voltage varies but the most common Is 500 volts. A megger voltage over 500 is NOT recommended.

When using a hi-pot tester or megger to measure Insu

lation resistance, be sure to follow the manufacturer's instruc tions carefully.

CAUTION: Before attempting to measure Insula

tion resistance In any winding, first disconnect any electronic components, regulators, diodes, surge protectors, protective relays, etc., from the

circuit. Such components will be destroyed by the high voltages generated by a megger or hl-pot

tester.

To measure Insulation resistance, connect one tester

lead to the leads for the winding to be tested and the other

tester lead to the generator frame. Make sure no leads of the

part being tested are touching any metal parts of the gener ator. If the 'Neutral' is grounded, it must be disconnected. Follow the tester manufacturer’s instructions and perform the resistance test.

Insulation Resistance- Main Stator

All stator leads (No. 11, 22, 33, 44, 2 and 6) must be Isolated from ground and connected together. Connect one hi-pot or megger test lead to the main stator leads. Connect

the other hi-pot or megger lead to the generator grounding

stud. Set the hi-pot tester or megger voltage to '500'. Follow

the tester manufacturer’s Instructions and take the reading.

Do not apply the voltage for longer than one (1) second.

If a hi-pot tester like the one shown in Figure 22 is being used, a 'Breakdown' lamp on the tester will glow during the one second test to indicate an Insulation breakdown.

If a megger is used to perform the test, the minimum acceptable value can be calculated using the following for mula:

Minimum Insulation в Resistance (Megohms)

Example: For a generator rated 240 volts AC:

2^+1b 1.24 Megohms

Generator Voltage +1

-------------TOOO

------

1000

H the reading Is below the recommended value, the winding must be dried out

Rotor insuiation Resistance

Before testing Rotor insulation, гтшке sure the Rotor Is completely Isolated. This can be done by removing both brush holders with their brushes.

Connect one hi-pot tester or megger lead to the positive Rotor slip ring, the other test lead to a clean frame ground (such as the Rotor shaft). Set the tester to '500' volts and apply voltage - DO NOT APPLY VOLTAGE LONGER THAN ONE SECOND.

If a hi-pot tester is used. Its 'Breakdown' lamp will come on to Indicate an insulation breakdown.

If a megger Is used, the minimum acceptable value Is 1.5 megohms. ,

If insulation Is breaking down under the applied voltage, the Rotor must be dried out. After drying, retest the Rotor. If insulation still breaks down after drying, replace the Rotor assembly.

Greasy dirt or dirt that Is caked may be loosened with a soft brush or a clean, damp cloth. A vacuum system may be used to clean up loosened dirt. Loose dust and dirt may also be blown away with clean, dry, low pressure air (25 psi maximum).

Drying the Generator

To dry the generator without disassembling it, proceed as follows:

1. Open the generator’s main circuit breaker. NO ELECTRI

CAL LOADS MUST BE APPLIED TO THE UNIT WHILE

DRYING.

Page 1.3-1

Cleaning the Generator

Drying the Generator (Continued)

2. Disconnect Wires No. 4 from the Voltage Regulator.

3. Provide an external source to blow warm, dry air through the generator. DO NOT EXCEED 185* F. (85* C.).

4. Start the generator and iet it run for 2 or 3 hours.

5. Stop the engine and retest Stator and Rotor insulation for breakdown.

Page 1.3-2

Section 1.4- INTRODUCTION TO TROUBLESHOOTING

A revolving field RV/IM type generator does not have a

Introduction

large number of parts. However, the parts are expensive. For that reason, a 'parts replacement' method of troubleshooting Is not cost effective. A basic understanding of generators is required if one Is to achieve effective troubleshooting and repair. The technician must understand why generators be have or don’t behave as they should. This section is Intended to introduce the service technician to some of the fundamen tals of troubleshooting generator problems.

DANGER: RV AND IM TYPE GENERATORS PRO DUCE EXTREMELY HIGH AND DANGEROUS VOLTAGES. CONTACT WITH LIVE WIRES AND TERMINALS MAY RESULT IN HAZARDOUS AND POSSIBLY FATAL ELECTRICAL SHOCK. ONLY

PERSONNEL WHO HAVE BEEN TRAINED IN THE SERVICING AND REPAIR OF RV/IM GENERA TORS SHOULD ATTEMPT TO TROUBLESHOOT, TEST OR REPAIR SUCH EQUIPMENT.

Tools and Equipment

The generator service technician should have a well stocked tool box having a good selection of common hand tools. Such a tool box should be equipped with wrenches in both english and metric sizes. A selection of nut drivers (english and metric) is also recommended. In addition to common hand tools, the following specialized equipment should be available;

Figure 24. A Typical Frequency Meter

1. Volt-Ohm-Milliammeter or VOM a. An accurate VOM Is necessary fortesting, adjusting and troubleshooting. b. Simply having a VOM is not enough- the technician must

be familiar with electrical circuits, must be able to read wiring diagrams and electrical schematics, and must be able to use the VOM effectively.

C. An accurate digital type VOM is recommended.

2. Frequency Meter a. Frequency meter reads alternating current (AC) fre

quency, in HERTZ or CYCLES PER SECOND. b. Generator AC output frequency must be known in order

to check and adjust engine-generator operating speed. See "ROTOR ROTATIONAL SPEECt in this section.

3. Insulation Resistance Tester a. See Section 1.3, ‘INSULATION RESISTANCE TESTS". b. This tester will allow the user to test Rotor and Stator

Insulation for breakdown under an applied voltage.

4. Load Bank- will permit a known electrical load to be applied

to the generator, i.e., fortesting and adjustment of the gener ator under load.

Rotor Rotational Speed

The revolving field (Rotor) is directly connected to the engine crankshaft and will rotate at the same speed as the engine. Engine speed is held nearly constant by an engine governor. Some generator models utilize a constant speed, MECHANICAL governor; other models may be equipped with an ELECTRONIC governor. See Part 7, "ENGINE SPEED

CONTROL SYST^Kr.

Generators may be equipped with either a 2-pole or a 4-pole Rotor. A 2-poie Rotor has a single North magnetic pole and a single South magnetic pole. A 4-pole Rotor has two

North magnetic poles and two South magnetic poles. The

following apply to 2 and 4-pole Rotor assemblies:

A. 2-Pole

Figure 25. Typical 2 and 4-Pole Rotors

B. 4-Pole

Page 1.4-1

Rotor Rotational Speed (Continued)

1. A 4-Pole Rotor must be operated at 1800 rpm to supply a 60 Hertz AC output frequency: or at 1500 rpm for a 50 Hertz AC output frequency.

2. A 2-pole Rotor must be operated at 3600 rpm for a 60 Hertz AC output frequency: or at 3000 rpm for a 50 Hertz frequency.

The following formulas apply to (a) frequency, (b) rpm, and

FREQUENCY = RPM X NO. OF ROTOR POLES

2x60

RPM o

NO. OF ROTO№ 2 X 60 X FREQUENCY POLES RPM

2 X 60 X FREQUENCY

NO. OF ROTOR POLES

Relationship of Voltage & Frequency

The generator’s AC voltage regulator mounts a single

adjustable potentiometer, used for adjustment of tne

Regulator’s REFERENCE voltage (see ’EXCITATION S/S-

TEAf on Page 1.1-4). The potentiometer is called simly a 'Voltage Adjust Potentiometer* and is adjusted with the gen erator running at no-load and at a specific operating speed.

It is important that the engine speed governor be properly adjusted before the Voltage Adjust Potentiometer setting is attempted. The no-load AC frequency and voltage settings should be as follows:

1. Shut the generator engine down.

2. Connect a voltmeter to the generator’s AC output

leads.

3. Disconnect Wires No. 4 and 1 from the Voltage Reg

ulator.

4. Connect a jumper wire from terminal #1 (Wire #15) of the engine control circuit board to the terminal end of Wire #4 (just disconnected from the Reguiator).

5. Connect a jumper wire from terminal #2 of the engine control circuit board (Wire #0, ground) and to the terminal end of Wire #1 Gust disconnected from the Regulator).

6. Start the generator and let It run at no-load (main breakers open) and at its rated speed.

7. Read the generator’s AC output voltage from the voltmeter connected In Step 2. Reading should be approxi mately one-half rated voltage (about 40-60 volts line-to-neutral or 80-120 volts line-to-line).

8. Shut the generator down.

9. Reconnect Wires No. 1 and 4 to the Voltage Regulator.

If voltage reading is normal in Step 7, the Wires #1 and 4 circuit, brushes and slip rings. Rotor and Stator are working satisfactorily. The problem is In the circuit that Includes (a) stator excitation windings, (b) thermal protector, (c)excitation circuit breaker (CB4), (d) Wires 2 and 6, and (e) Voltage

Regulator.

NOTE: Field boost current la available to the Rotor only

while the engine Is cranking. Loss of excitation current flow to the Rotor will result In a decrease In generator AC output voltage to a value commensurate with Rotor re

sidual magnetism (about 2 to 7 volts AC),

1. For Units Rated 120/240 Volts at 60 Hertz: Set AC frequency to 60.5-63.5 Hertz and Voltage to 121-127 volts AC (line-to-neutral), or 242-254 volts AC (line-to-line).

2. For units rated 110/220 volts at 50 Hertz: Set AC fre quency to 49-52 Hertz and voltage to 108-112 volts (line-toneutral).

Visuai inspection

Quite often problems that occur in the generator can be detected by making a thorough visual inspection. Remove covers and look for any obvious problems. Burned windings, broken connections, leads, mounting brackets, etc., can usu ally be Identified. Also look for loose or frayed insulation, loose or dirty electrical connections, broken wires.

Verify that the generator AC output leads are properly connected for (a) single voltage outpiut, or (b) dual voltage output. See 'STATOR AC POWER CONNECTION SV%-

TEMSr on Page 1.1-5.

Check for any foreign objects, loose nuts, bolts, and electrical connectors. Clear away paper, leaves, snow, build ing materials, etc., that might be sucked into the generator.

Constant Excitation Test

The generator’s AC output voltage will vary with Rotor speed, generator design, connected loads, and excitation current to the Rotor, if the generator speed and excitation cunenttothe Rotor are known, the no-load AC output voltage can be measured and compared to the design value. A problem can be isolated to (a) Stator Excitation (OPE) wind ings to Voltage Regulator circuit, including the Regulator, or (b) Voltage Regulator to Rotor circuit, excluding the Regula tor, or (c) the Stator assembly. Perform the test as follows:

a DC or AC voltage.

The DC voltage most often measured will be battery

voltage (12 volts DC).

When measuring AC voltages, the generator will have to

be running at rated speed and may have some of the protec

tive guárete and covers removed. BE CAREFUL. It is best to

shut the unit down when connecting meters. Use the meter’s instruction manual to verify its operation and limitations.

Page 1.4-2

Alternating current measurements can be taken with a

Measuring Current

'clamp-on* type ammeter. Amperage should never exceed the nameplate rating when running the intended electrical load(s).

Resistance of the main stator windings is very low. Some meters are not able to read such a low resistance and, for that reason, use of a very sensitive digital type meter is recom mended. A standanj VOM can be used to check for continuity, shorts or grounded condition.

Effects of Engine Power

The generator engine must provide adequate power to operate the generator at rated load. The greater the load current (amperage) or load watts, the greater the engine power that is needed. As a general rule, approximately 2 engine horsepower is needed for each 1000 watts (1.0 kW) of generator power.

If the generator’s wattage/amperage capacity is ex

ceeded, engine power may not be sufficient to handle the

Increased load. The result will be a decrease in engine speed (rpm) and a corresponding reduction int AC output frequency

and voltage.

A badly worn engine, one that has lost compression, or one with a mechanical problem may not be able to handle a

load within the generator’s rated capacity. Problems with

generator AC output are often the direct result of an engine

problem, rather than a generator problem.

If engine speed, AC frequency and voltage are normal when the generator Is running aty no load, but deteriorate when electrical loads are applied, an underpowered engine

may be the cause of the problem.

Measuring Resistance

Page 1.4-3

Section 1.5- TROUBLESHOOTING FLOW CHART

TEST 1-CHECK NO-LOAD

VOLTAGE AND FREQUENCY

VOLTAGE & FREQUENCY BOTH GOOD

VOLTAGE &

FREQUENCY

BOTH HIGH

IVQEVOLTAGE LOW,

FREQUENCY

GOOD

VOLTAGE

AND

FREQUENCY

Page 1.5-1

Using the Troubleshooting Flow Chart

When a problem occurs with an RV/IM series generator

set, the first step is to determine exactiy what that problem is. The nature of the problem can usually be found by checking the unit’s no-load AC output voltage and frequency. This is Test 1 in the Flow Chart. A check of the no-load voltage and

frequency will usually end with one of the following results;

1. Voltage and frequency are both good. If this is the case,

the next step is to check voltage and frequency with electrical

load applied.

2. Voltage and frequency are both high or bw, usually an

engine governor problem, I.e., governed speed too high or

too low.

3. Voltage is low, but AC frequency is good. The cause of this problem can often be found by perfomiing a "Fixed Excitation" test

4. Voltage and frequency read "zero". Once the nature of the problem is defined, the cause of

the problem can usually be found by following the explana tions and arrows in the Flow Chart

Use the'TROUBLESHOOTING FLOWCHART in con

junction with test instructions in Section 1.6, 'TROUBLE

SHOOTING TEST PROCEDURES'.

r-\

Page 1.5-2

Section 1.6- TROUBLESHOOTING TEST PROCEDURES

The following numbered tests may be performed in con

Introduction

junction with identically numbered tests in the "TROUBLE

SHOOTING FLOW CHART (Section 1.5). The "FLOW

CHART* has been carefully planned to prevent guesswork and to locate most common generator problems.

NOTE: Quite often the cause of a problem can be deter mined by completing a close visual Inspection of the generator. See "VISUAL INSPECTION" on Page 1.4-2.

Test 1> Check No-Load Voltage and Fre

quency

DISCUSSION:

When a generator problem occurs, the first step Is to identify the problem. This can usually be accomplished quickly by checking the no-load AC ouÿut voltage and fre quency. Once the exact problem has been identified, the cause of the problem can usually be isolated by continuing orderly tests as shown in the "TROUBLESHOOTING FLOW CHART".

NOTE: You will have to determine whether the AC leads have been connected for single voltage output only (120

volts, 60 Hertz orilo volts, SO Hertz); or for dual voltage output (120/240 volts, 60 Hertz or 110/220 volts, 50 Hertz). See "STATOR AC POWER CONNECTION SYSTEMS" on

Page 1.1-5.

PROCEDURE:

1. Connect an AC voltmeter and AC frequency meter across

the generator’s AC output leads. Open main circuit breaker.

a. If connected for single voltage AC output, connect the meters across leads T1 and 12.

b. If connected for dual voltage output, connect meters across leads T1 and 12 or 12 and T3 for a 120 volts, 60 Hertz (or 110 volts, 50 hertz) reading. For a 240 volts, 60 Hertz (or 220 volts, 50 hertz) reading, connect meter test leads across generator leads T1 andT3.

2. Start the generator engine, let It stabilize and wami up.

3. Read the AC output voltage and frequency. Readings

should be as follows:

a. For units rated 120/240 volts, 60 hertz; readings should be 121 -126 volts at 61 -63 Hertz; or 242-252 volts at 61 -63 Hertz.

b. For units rated 110/220 volts, 50 hertz; readings should be 111 -113 volts at 51 -53 Hertz; or 222-226 volts at 51 -53 Hertz.

RESULTS:

1. If the no-load voltage and frequency are good, go to Test

2. If no-load voltage and frequency are both high or low, go

to Test 5.

3. If frequency reads good but voltage Is low, go to Test 6.

4. If voltage and frequency read "zero", go to Test 1.0.

Test 2- Check Load Voltage and Fre

quency

DISCUSSION:

Generator problems are sometimes caused by exceed

ing the wattage/amperage capacity of the unit. What appears

to be a generator problem may, in fact, be caused by an

engine that has lost power. The following facts apply:

D Quite often, the maximum wattage that can be supplied

by a generator Is limited by available engine power. When connected loads exceed a critical point, engine speed will droop. With a reduction in engine speed will come a voltage and frequency loss.

O It is possible that an engine can lose power to the extent

that even normal rated generator output power can be achieved. Engine speed, frequency and voltage can then droop before a unit's rated maximum capacity has been reached.

PROCEDURE:

If no-load AC output voltage and frequency were within limits, but operational problems occur when electrical loads are applied, check the output voltage and frequency under load as follows:

1. Connect an AC voltmeter and frequency meter across the

generator’s AC output leads. Close the main circuit breaker.

2. Start the generator, let it stabilize and warm up.

3. Apply an electrical load to the generator equal to its rated maximum wattage/amperage capacity.

4. Read the voltage and frequency.

a. Units rated 120/240 volts, 60 Hertz: Readings should be at least 116 volts and 58 Hertz (or higher).

b. Units rated 110/220 Volts, 50 Hertz: Readings should be at least 107 volts, 48 Hertz (or greater).

RESULTS:

1. If load voltage and frequency are below limits, go to Test

2. If voltage and frequency are good, discontinue tests.

Test 3- Check Load Watts and Amperes

DISCUSSION:

If the unit's AC output frequency and voltage drop below

limits when electrical loading is applied, it is possible that the rated capacity of the generator has been exceeded.

PROCEDURE:

Add up wattage ratings of all electrical loads applied to

the generator at one time. This total should not be greater

than the unit’s rated maximum wattage capacity. If desired, a clamp-on ammeter may be used to measure load current. The unit’s rated maximum amperage capacity should not be ex ceeded.

Page 1.6-1

Test 3- Check Load Watts and Amperes

(Continued)

NOTE; The best way to check load wattage and amperage la to use a load bank. A load bank will allow the operator to apply a known wattage/amperage load to the generator and win permit voltage, frequency and amperage to be read directly from the load bank.

RESULTS;

1. If the generator Is overloaded, reduce the load to the unit’s rated capacity.

a. If voltage and frequency are excessively low at the unit’s rated capacity or less, go on to Test 4.

b. If voltage and frequency are acceptable at the unit’s

rated capacity, discontinue tests.

2. If the load Is within the unit’s rated capacity, but load voltage and frequency are excessively low, go on to Test 4.

Test 4- Check Engine Power

DISCUSSION:

If excessive rpm and frequency droop occurs when electrical loads are applied, the engine may be underpowered due to a malfunction.

PROCEDURE:

Check the engine for (a) adequate air flow, (b) clogged air cleaner, (c) incorrect timing, (d) mechanical failure, etc.

RESULTS:

1. If engine problems are found, repair the engine as neces sary.

2. If engine checks good, go on to Test 5.

Test 5- Check & Adjust Engine Governor

DISCUSSION:

If engine speed (and frequency) droop excessively under load, the engine governor may require adjustment

PROCEDURE:

Refer to Part 7, "ENGINESPEED CONTROL SYSTEM-. Governor adjustment procedures for both the mechanical and electronic type governors can be found in Part 7.

RESULTS:

1. It, after governor adjustment, voltage and frequency output at no-load and under load are good, discontinue tests.

2. If, after governor adjustment, frequency Is good, but volt age is excessively low, go on to Test 6.

Test 6- Do a Fixed Excitation Test

DISCUSSION:

See "CONSTANTEXCITATION TEST on Page 1.4-2.

PROCEDURE:

’TEST" on Page 1.4-2.

RESULTS:

1. If voltage is excessively low, go to Test 7.

2. If about 1/2 rated volts is indicated, go to Test 12.

Test 7- Check Wires 1 and 4

DISCUSSION:

the fixed or constant excitation test (Test 6) consisted

of applying battery direct current to the Rotor windings (12

volts DC). With the normal excitation circuit disconnected,

application of battery current should result In approximately one-half rated voltage output (about 60-80 volts AC).

If batteiy current is applied and AC output voltage te excessively low, a problem exists in Wires 1 and 4 from the Regulator, or the brushes and slip rings, or the Rotor or stator windings.

If the application of battery current results in an AC output of about one-half rated volts, but AC output voltage is low during normal operation, a problem exists in the stator exci

tation (DPE) windings, in the excitation circuit between the

stator DPE windings and the Regulator, or in the Regulator itself.

PROCEDURE:

1. Visually inspect Wires 1 and 4, between the Voltage Regulator and the brushes.

2. Use a VOM to test Wire 1 (between the brushes and Regulator) for continuity.

3. Check Wire 4 (between the brushes and Regulator) for continuity.

4. Check that Wires No. 1 and 4 are properly connected at

the Regulator and at the brushes.

RESULTS:

1. Repair, replace or reconnect wires 1 and 4 as necessary.

2. If Wires 1 and 4 are good, go to Test 8.

Test 8- Check Rotor

DISCUSSION:

Problems will be encountered if the Rotor Is (a) open, (b)

shorted, or (c) grounded. This test will determine If any of

these problems exist in the Rotor.

PROCEDURE:

1. If Rotor Is installed, remove the bearing carrier cover to

gain access to the Rotor brushes and slip rings.

2. Disconnedct Wires 1 and 4 from the brushes, to prevent Interaction.

3. Connect the positive test lead of an ohmmeter to the positive slip ring, the common test lead to the negative slip ring. The positive slip ring Is the one nearest the Rotor bearing (see Figure 28). The meter should indicate the resistance of

the Rotor windings, approximately 8.5 ohms (plus or minus

10%) for both 8 and 10 kW models.

4. Set a VOM to a very high resistance scale, such as

■Rxl 0,000" or "RxlK". Zero the meter. Connect the positive

VOM test lead to the positive slip ring. Connect the negative VOM test lead to a clean frame ground, such as the Rotor shaft. The meter should read "infinity".

RESULTS:

1. In Step 3, a very high resistance or "infinity" Indicates an

open or partially open condition. Replace the Rotor.

2. In Step 3, a very low resistance indicates a shorted or

groundea condition. Replace the Rotor.

3. In Step 4, any reading other than "infinity" Indicates a

groundea condition. Replace the Rotor.

4. If all Rotor readings are good, go to Test 9.

Page 1.6-2

Figure 28. Checking Rotor Resistance

Test 9> Check Brushes and Slip Rings

DISCUSSION:

if the fixed (constant) excitation test did not result in an AC output voitage of approximateiy one-haif rated voits, one possibie cause of the probiem might be defective brushes and/or slip rings.

Test 10- Test Main Circuit Breaker

DISCUSSION:

■ If AC output voltage and frequency are "zero", one pos sible cause of the problem is an open or failed main circuit breaker.

PROCEDURE:

Make sure the main circuit breaker Is set to Its ’Closed’

position, if the breaker Is closed, check it for continuity.

RESULTS:

1. Replace main circuit breaker. If It Is defective.

2. If main breaker is good, go to Test 11.

Figure 30. Main Circuit Breaker (Typical)

PROCEDURE:

Remove Wires 1 and 4 from the brushes. Then, remove

the brush holders from the rear bearing carrier. Inspect the

brushes and brush holders. Replace, It cracked, damaged,

worn excessively, etc.

Inspect the slip rings. If they are dull or tarnished, they can be cleaned with fine sandpaper. DO NOT USE ANY METALLIC GRIT TO CLEAN SLIP RINGS. Use low pressure air (25 psi or less) to blow away cleaning residue.

Reassemble brushes and brush holders to rear bearing carrier. Make sure brushes are properly seated in brush

holders and are contacting the slip rings properly. Reconnect Wires 1 and 4 to brushes. Rotate the Rotor several times to seat the brushes against the slip rings.

RESULTS:

Clean slip rings, replace bad brushes or brush holder(s)

as necessary.

Test 11- Check AC Power Lead Connec

tions

DISCUSSION:

The stator's AC output leads must be property connected as outlined under ‘STATOR AC POWER CONNECTION SYSTEMSr (Page 1.1-5).

PROCEDURE:

Check that Stator AC output leads 11,22,33 and 44 (as well as T1, T2 and T3) are property connected as shown In the appropriate wiring diagram/schematic. Reconnect wires as necessary.

RESULTS:

Reconnect, repair or replace stator AC output leads as

necessary.

Test 12- Test DPE Circuit Breaker

DISCUSSION:

The excitation (DPE) circuit breaker is connected in series with lead 2 (or 2A) between the stator excitation (DPE) windings and the voltage regulator. If the breaker should open, excitation winding AC output to the Regulator will be lost and AC ou^ut from the generator will drop to a voltage that is commensurate with the Rotor’s residual magnetism (about 2 to 7 volts AC). Application of fixed excitation current p est 6) will result in an AC output voltage equal to approxi mately one-half rated voltage.

Page 1.6-3

Test 12< Test DPE Circuit Breaker (Con

tinued)

PROCEDURE:

1. With the generator shut down, disconnect the leads from the two breaker terminals, to prevent interaction. Then, connect the test leads of a volt-ohm-milliammeter (VOM) across the two circuit breaker terminals. The meter should read continuity or a very small resistance.

a. If meter indicates 'continuity' or a small resistance, go to Step 2.

b. If the meter reads 'infinity' replace the circuit breaker.

2. Reconnect the two leads to the circuit breaker terminals.

3. Start the generator engine.

4. Check the generator's AC output voltage (see Test 1).

a. if AC output voltage is excessively low, go to Step 5. b. If AC output voltage is normal, discontinue tests.

5. Connect a jumper wire across the two terminals of the excitation (DPE) circuit breaker. Again, check the unit’s AC output voltage.

RESULTS:

1. In Step 1, if the meter reads 'infinity' it should be replaced.

2. If AC output voltage was excessively low in Step 4, but normal in Step 5, replace the excitation (DPE) circuit breaker.

RESULTS:

1. If the VOM indicated excitation winding resistance in Step 4, but read 'infinity' in Step 6, the thermal protector will have to be bypassed as follows:

a. Cut Wire 2 as close as possible to the end of Wire 5. b. Strip the Insulation from the end of Wire 2 that goes to

the excitation circuit breaker.

c. Strip the iunsulation from the end of Wire 5. d. Connect the stripped ends of Wire 2 and 5, retain with

the wire nut.

2. If the meter indicated excitation winding resistance In both Steps 4 and 5, go to Test 14.

Figure 32. Thermal Protector In the Circuit

Test 13- Test Thermal Protector

DISCUSSION:

Also see 'THERMAL PROTECTOR' on Page 1.1-4. A thermal protector that has failed open will cause the same effects as an excitation circuit breaker that has failed open.

PROCEDURE:

1. Disconnect lead 2 from the excitation circuit breaker.

2. Disconnect lead 6 from the Voltage Regulator.

3. Locate lead 5. This lead is brought out of the Stator and is

unattached. A wire nut covers its end.

4. Connect the test leads of a VOM across leads 5 and 6. The

meter should read a small resistance (the resistance of the

Stator excitation winding).

5. Now, connect the VOM test leads across leads 2 and 6. Again, the resistance of the Stator excitation windings shouid be indicated (about 0.73 ohm for 10 kW units; 1.00 ohm for 8

kW units).

A. Pictorial

Figure 33. Thermal Protector Bypassed

B. Schematic

CXCrTATtON

rr*T)ON I

^ ^ WINDINO

-.-t

ÓO

TO EXCrTATION

A. Pictorial

Test 14- Test Stator DPE Windings

DISCUSSION:

An open condition in the stator excitation windings wiii

result in loss of excitation output to the Voltage Regulator. The Regulator will then shut down and generator AC output voltage will drop to a value commensurate with Rotor residuai

magnetism (about 2-7 volts).

A grounded or shorted condition will also result in prob lems with generator AC output. This test will test the Stator excitation windings for (a) open condition, and (b) for a grounded condition.

ClftClHT BBBAKER

B. Schematic

Page 1.6-4

NOTE: Before attempting to test the Stator excitation winding, be sure the thermal protector has not failed open. See Teat 13.

PR^OCEDURE:

1. Disconnect Wire 2 from the excitation circuit breaker (CB4).

2. Disconnect Wire 6 from the Voltage Regulator.

3. Use a VOM to test the resistance of the excitation windings. Connect the VOM test leads across leads 2 and 6. The VOM should indicate the resistance of the excitation windings.

a. For 8 kW units, reading should be approximately 1.00

ohm (plus or minus 10%).

b. For 10 kW units, resistance should be approximately

0.73 ohm (plus or minus 10%).

4. Now, set the VOM to a high resistance scale such as "Rxl 0,000’ or *Rx1 K’. Zero the meter. Connect one VOM test lead to Wire 6, the other test iead to a clean frame ground on the Stator. The meter should read 'Infinity'.

RESULTS:

1. If stator excitation windings fall the test, replace the Stator assembly.

2. If excitation windings check good, go to Test 15.

Test 15- Test Stator AC Power Windings

DISCUSSION:

An open or shorted condition in the Stator will adversely affect generator AC voltage output. This test will check the AC power windings for (a) open condition, (b) grounded condition, and (c) short between parallel windings.

PR^OCEDURE:

1. Disconnect and isolate Stator leads 11,22,33 and 44. Also

disconnect and isolate Stator leads 5 and 6.

2. Set a VOM to Its 'Rxl' scale and zero the meter.

3. Connect the VOM test leads across stator leads 11 and

22.

a. For 8 kW units, the meter should read approximately

0.21 ohm. b. For 10 kW units, the VOM should indicate approximately

0.14 ohm.

NOTE: The actual realatance will vary slightly with tem perature, with a nominal variation as much as plus or mlnua 10 percent.

4. Connect the VOM test leads across stator leads 33 and 44. Resistance readings should be the same as In Step 3(a) and 3(b).

5. Now, set the VOM to a high resistance scale, such as ’Rx10,000' or 'RxlK'. Zero the meter. Connect one meter test lead to stator lead 11, the other test lead to stator lead

33.

a. The meter should read 'infinity'. b. Any reading other than 'infinity' Indicates a short be

tween parallel windings.

6. With VOM still set for a high resistance, connect one VOM test lead to stator lead 11, the other test lead to a clean frame ground on the stator. Repeat the test with one test lead attached to stator lead 33 and the other connected to a clean frame ground on the stator.

a. The VOM should read '1011011/. b. Any reading other than 'Infinity' Indicates a grounded

condition.

7. With the VOM still set for a high resistance, connect one VOM test lead to stator lead 11, the other to stator lead 5.

Repeat the test with one VOM test lead connected to stator lead 33, the other to stator lead 5.

a. In both cases, the meter should read 'Infinity'. b. Any reading other than 'infinity' Indicates a short be

tween windings.

RESULTS:

1. If any reading is bad, replace the stator assembly.

2. If stator checks good, go to Test 16.

Test 16- Check Sensing Leads

DISCUSSION:

The Voltage Regulator must sense ACTUAL AC power winding voltage. Itr must then electronically 'compare' the ACTUAL voltage to a REFERENCE voltage that is preset In the Regulator. The Regulator acts to maintain an actual voltage that is the same as the reference voltage by regulat

ing excitation current flow to the Rotor.

If ACTUAL voltage sensing signals to the Regulator become lost for any reason, the normal reaction of most Regulators would be to think' that ACTUAL voltage Is too low. The Regulator would then Increase excitation current flow to the Rotor in an attempt to increase the ACTUAL voltage. That is, the Regulator and Rotor would go to a 'Full Field''^ condition and the generator’s AC output vdtage would go to a very high maximum value.

However, the Voltage Regulator used on RV/IM models is equipped with a 'sensing loss cutout' feature. That is, when loss of sensing signals occurs, the Voltage Regulator will shut down. When the Regulator shuts down, a complete loss of excitation current flow to the Rotor will occur. The actual AC output voltage will then drop dramatically to a value commen surate with Rotor residual magnetism (about 2 to 7 volts AC).

PROCEDURE:

1. With the generator running, observe the red LED (light emitting diode) on the AC voltage regulator. If sensing voltage is available to the regulator, the light should be ON.

a. if the light is OUT, complete Step 2 below. b. If the light is ON, go to Test 17.

2. Connect an accurate AC voltmeter across the Voltage Regulator sensing terminals (leads 11 and 22). The meter should Indicate line-to-neutrai voltage. If not, complete the following:

a. Carefully Inspect sensina leads 11 and 22, between the engine control circuit board and the Voltage Regulator.

b. Inspect leads 11 and 22 between the engine control circuit board and the AC connection panel.

c. Use a VOM to check sensing leads 11 and 22 for an open or shorted condition.

RESULTS:

1. Reconnect, repair or replace any damaged, open, shorted or defective sensing leads.

2. If sensing leads are good, go to Test 17.

Test 17- Check Voltage Regulator

DISCUSSION:

The Voltage Regulator Is discussed under Test 16 above, as well as on Page 1.1-4. The Regulator Is equipped with two safety features, as follows:

Page 1.6<^

Test 17- Check Voltage Regulator (Con

tinued)

1. Sensing loss shutdown- if sensing is not availabie to the Regulator (sensing leads 11 and 22), the Regulator will shut

down.

a. With the Regulator shut down, loss of regulated excita tion current to the Rotor will occur.

b. The generator’s AC output voltage will drop to a value commensurate with Rotor residual magnetism (approxi mately 2-7 volts AC).

c. The red LED (light emitting diode) on the Regulator is a sensing indicator. The light will go OUT when sensing signals to the Regulator (wires 11 and 22) are not avail able. It should remain ON during operation, indicating that sensing voltage is available.

2. Voltage limiting- maximum AC output voltage is limited to a maximum of approximately 140-145 volts AC (llne-to-neutral).

PROCEDURE:

If a zero or low AC output voltage condition exists and

you have completed all previous tests Indicated in the Trou

bleshooting Flow Chart", you might try adjusting the Voltage Regulator. If attempts to adjust the Regulator do not produce positive results, replace the Regulator. Then, adjust the Regulator and test generator operation.

Page 1.6-6

Part 2

ENGINE

MECHANICAL

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERATORS

Liquid Cooled 1.2 Liter

Gas Engine Models

SECTION

2.1

2.2

2.3

2.4

2.5

2.6

TABLE OF CONTENTS

TITLE

Basic Engine Mechanical

Timing Belt

Cylinder Head Oil Pan and Oil Pump Oil Seal Replacement

Engine Overhaul

Section 2.1- BASIC ENGINE MECHANICAL

This section covers some of the basic engine servicing

Introduction

tasks. Included In the Section are commonly used tightening

procedures for cylinder head bolts, manifold nuts and carbu retor bolts. Also covered are valve clearance adjustment and drive belt checking procedures.

Tightening Cylinder Head Boits

RetIghten cylinder head bolts while the engine Is cold, at

approximately 68* F. (20* C.). Tighten the bolts as follows:

1. Remove all spark plugs, oil pump drive gears, retainer and bolts (Figure 1).

1. Set No. 1 cylinder at top dead center (TDC) of Its compres

sion stroke. Then, adjust valve clearance 1,2,3 and 6.

2. Set No. 4 cylinder at top dead center (TDC) of its compres sion stroke and adjust valve clearance 4, 5, 7 and 8.

3. Set valve clearance as follows:

VALVE CLEARANCE HOT

INTAKE s 0.010 Inch (0.25mm) EXHAUST = 0.012 Inch (0.30mm)

Figure 3. Valve Clearance Adjustments

(i) d) (z)

4. When valve clearances are properly set, tighten the adjust ing screw locknut to 8-11 foot-pounds (11-15 N-m).

2. Tighten bolts to 47-51 foot-pounds (64-69 N-m) in the sequence shown below.

Tighten Manifoid, Exhaust Manifoid and

Carburetor Fasteners

INTAKE MANIFOLD NUTS:

Tighten to 12-15 foot-pounds (16-21 N-m).

EXHAUST MANIFOLD NUTS:

Tighten to 12-15 foot-pounds (16-21 N-m).

CARBURETOR BOLTS:

Tighten to 4.3-5.8 foot-pounds (6-8 N-m).

Adjusting Vaive Clearance

Adjust valves while engine is warm, but not running, as

foltows:

Inspect drive belts for cracks, fraying, wear, ollllness.

Checking Drive Beits

Replace, if necessary. The belts should not touch the bottom of the pulley groove. To check belt tension, apply a force of approximately 22 pounds (10 kg) midway between pulleys. Belt deflection should be as follows:

NEW BELT a 0.59^).75 inch (15-19m)

USED BELTaO.71-0.87 inch (18-22mm)

Measuring Compression Pressure

Warm up the engine. Then, shut down and remove ail spark plugs. Use a standard automotive type compression gauge. Hold the throttle and choke valves on carburetor wide open.

Page 2.1-1

Measuring Compression Pressure (Continued)

then crank the engine and read the compression pres

sure. The pressure reading shouid be as follows:

^TANDAR^^^9278MiT5kg7clT?)at35^^

MINIMUM n 164 psi (11.5 kg/cm^) at 350 rpm DIFFERENCE BETWEEN CYLINDERS SHOULD NOT

EXCEED 14 PSI (1.0 kg/cm^)

If the compression reading is low in any cylinder, pour a small amount of clean engine oil into the cylinders through the spark plug opening. Then, retest compression and eval

uate as follows:

D If compression pressure increased after adding the oil,

check for worn or damaged piston rings or worn cylinder

walls. n If pressure did NOT increase after adding oil, valve(s)

may be sticking or seating improperly. D If compression in any two adjacent cylinders is low and

adding oil did not increase compression, check for a

leaking head gasket

Page 2.1-2

Section 2.2- TIMING BELT

Timing Belt Precautions

Comply with the following precautions when removing,

Installing or inspecting the timing belt:

D Make sure the timing belt, pullies and belt tensioner are

free of oil and water.

□ Prior to installing the timing belt, make sure that No. 1

cylinder is at top dead center (TDC) of its compression stroke.

D Align the arrow on the timing belt in the direction of

engine rotation.

G Remove all spark plugs before adjusting timing belt

tension.

□ Once the timing belt has been removed, DO NOT rotate

the crankshaft and camshaft separately, or the valves will strike the piston heads.

Q Do NOT bend or twist the timing belt too tightly.

Timing Beit Removai

1. Drain the radiator.

2. Remove the radiator, fan guard and fan. See Part 4,

“ENGINE COOLING SYSTEM".

3. Remove tension from the drive belt, then remove the drive belt.

4. Remove the crankshaft pulley.

5. Set No. 1 cylinder at top dead center (TDC) of its compres

sion stroke. Then, remove upper and lower dust covers and

gaskets.

6. Loosen timing belt tensioner and return spring, then re move timing belt.

Timing Beit Inspection

BELT IS BROKEN;

Caused by improper han dling, poor belt cover sealing, coolant leakage at water

pump.

Timing Belt Inspection (Continued)

TOOTH BROKEN OR TOOTH ROOT CRACKED:

Caused by camshaft jamming, distributor jamming, damaged crankshaft or camshaft oil seal.

BACK SURFACE CRACKED OR WORN:

Caused by tensioner jamming, overheated engine, interference with

belt cover.

SIDE SURFACE WORN:

Caused by Improper belt instal lation, defective crank pulley and/or timing belt plate.

CAUTION: The timing belt must be clean and free of oil and water. Do NOT bend the belt. Arrow on belt must point In normal direction of rotation.

Figure 14. Tensioner and Return Spring

NOTE: Replace the timing belt If (a) side surface Is worn

to such an extent that cutoff performed during the man ufacturing process cannot be seen, (b) belt comers are worn or rounded, or (c) belt fibers are frayed and coming out.

BELT TEETH ARE WORN:

Caused by poor belt cover seal

ing, coolant leakage at water pump, defective camshaft, defective distrib utor, excessive belt tension. Some problems that might be found under

Belt Teeth are Worn” include (a) can vas on tooth face worn, (b) canvas on tooth is fluffy, (c) rubber layer worn or faded white, or (d) weft worn or invis

ible.

Timing Belt Installation

1. Check that No. 1 cylinder is at top dead center (TDC) of Its

compression stroke. Align the camshaft and crankshaft pulley

marks. See Figure 13.

2. See Figure 14. Install tensioner and return spring. Hook the return spring to its stopper.

3. Slide the tensioner to the left and tighten the lock nut

temporarily (Figure 15).

4. Check that the water pump and tensioner pulleys can be

rotated smoothly and with no evidence of binding. Then,

install the timing belt.

Page 2.2-Z

Timing Beit instaiiation (Continued)

5. Loosen the tensioner lock nut. With all spark plugs re moved, rotate the camshaft pulley two full turns counterclock wise. Tighten the tensioner lock nut.

6. Check belt tension. With a force of 1.06-1.28 pounds applied, the belt should deflect about 0.08 Inch (2mm).

7. Tighten the tensioner lock nut to 11-12 foot-pounds (15-17 N-m).

Section 2.3- CYLINDER HEAD

Cylinder Head Removal

1. Remove timing belt (Section 2.2). Then, remove OIL PUMP IDLER GEAR.

Figure 21. Remove Valve Component Parts

2. Remove the cylinder head. Loosen bolts in 2 or 3 stages, in the sequence shown above.

screwdriver.

4. Remove the Camshaft (Figure 20).

5. Remove valve components parts (Figure 21).

6. Use a suitable puller to remove valve oil seals (Figure 22).

Checking Cylinder Head Distortion

Use a thickness gauge and a straightedge to measure

cylinder head distortion. See Figure 23 (next page). Lay the

straightedge across the cylinder head surface as shown. Surface warpage must not exceed 0.004 inch (0.1 mm). If the cylinder head exceeds the stated value, it must be replaced.

Resurfacing Limit: The amount of resurfacing that can be done on the cylinder head depends on the amount of resur facing on the cylinder block. If the amount of HEAD surfacing

is "A^and the amount of BLOCK surfacing is "B“, the maxi

mum limit is as follows:

Page 2.3-1

Checking Cylinder Head Distortion (Con

tinued)

Use a suitable dial indicator to measure valve stem to

Valve Guide Clearance

guide clearance. The valve should be moved parallel to the rocker arm, since most of the wear occurs in this direction. See Figure 24.

Figure 24. Valve Guide Clearance

Stem to guide clearance:

Maximum limit

0.10 mm (0.0039 in) Max. allowable deflection (Dial indicator readirrgi

0.2 mm (0.008 in)

Valve Guide Replacement

If valve guides must be replaced, proceed as follows:

1. Heat the cylinder head to 302‘-320‘ F. (150‘-160' C.) in an

oil bath (Figure 25).

2. Use a press exerting a 2.2 U.S. ton (20 kN) force to remove valve guides. If a press is not available, use a hammer and a suitabfe driving tool (Figure 26).

3. Ream the cylinder head's valve guide hole (Figure 27).

Page 2.3-2

5. Ream the valve guides to a finished size of 0.2758-0.,2764 inch (7.005-7.020mm).

Camshaft Bearing Clearance

Check camshaft bearing clearance (Figure 31). Check both the bore and the bearing outside diameter (O.D.). The difference between the two measurements is the bearing clearance. Maximum bearing clearance is shown below:

MAXIMUM CAMSHAFT BEARING CLEARANCE

0.0059 Inch (0.15mm)

Inspect valve inserts for evidence of pitting at valve

Valve Inserts

contact surfaces. Reseat or replace, if worn or pitted exces sively. The following rules apply:

D When repairing valve inserts, first check the valve and

valve guide for wear. If worn, replace them. Then, correct the valve seat.

□ When cutting, use both hands for more uniform cutting.

Figure 30.

Use a suitable measuring device to check camshaft

runout (Figure 33).

If necessary, replace valve inserts as follows:

1. Ream the cylinder head recess.

2. Heat the cylinder head to 302‘-320’ F. (150'-160‘ C.).

3. Install the insert. Make sure it bends at bottom face of its recess and caulk at more than 4 places.

4. Use a suitable tool to grind newly fitted valve seats. Grind

the seats to the specifications listed in the applicable SPEC

IFICATIONS chart.

5. Apply a small amount of valve grinding compound to the

valve contacting face and place valve into guide.

Page 2.3-3

Check dimensions of all valves. Refer to the appropriate

Valve Dimensions

SPECIFICATIONS chart.

Figure 34. Valve Dimensions

T (Margin thickness!

NOTE: When the valve head Is worn to 0.020Inch (0.5mm) margin thickness, replace the valve. Grinding allowance

for valve stem end surface Is 0.008 Inch (0.2mm) or less.

Valve Spring Squareness, Free Length

and Tension

Valve spring out-of-squareness must not exceed 0.079 inch (2.0mm). Refer to appropriate SPECIFICATIONS chart for spring free length and tension.

2. Install camshaft assembly. Note positioning of camshaft front face when No. 1 cylinder is at top dead center (TDC) of its compression stroke.

3. Measure camshaft end play with thermostat housing and gasket installed.

1. Install valve oil seal. Then, install valve component parts.

Cylinder Head Assembly

Apply engine oil to camshaft oil seal and install the seal.

Page 2.3-4

5. Install bolt stoppers. Always use NEV\/ bolt stoppers. See Figure 40, next page.

Cylinder Head Assembly (Continued)

6. Install oil pump Idler gear and oil pump regulator spring. Make sure the spring faces in the proper direction.

Figure 41.

Oil pump spring stopper

Oil pump regulator spring ^

Oil pump drive gear

Installation

1. Set No. 1 cylinder head at top dead center (TDC) of its

compression stroke by first aligning the CAMSHAFTTIMING

PULLEY MARK with mark on the main bearing cap.

2. Install cylinder head with a new gasket. The following rules apply:

D Always use a new cylinder head gasket. D Before tightening the cylinder head bolts, check that the

oil pump drive gear can be turned freely by hand. D Always installwashers between bolts and head. D Tighten cylinder head bolts in the sequence shown in

Figure 43.

3. Tighten cylinder head bolts as follows: a. First, tighten all bolts to 22 foot-pounds (29 N-m). b. Then, tighten all bolts to 47 foot-pounds (64 N-m). c. Loosen all bolts completely. d. Tighten all bolts to 22 foot-pounds (29 N-m). e. Tighten all bolts to 47-51 foot-pounds (64-69 N-m).

NOTE: When RETORQUING cylinder head bolts for nor mal periodic maintenance, first loosen all bolts slightly.

Then (with engine COLD), tighten all bolts In correct

sequence to 47-51 foot-pounds (64-69 N-m).

4. Install timing belt. Install oil pump Idler and oil pump

regulator spring (make sure spring direction is correct). Install upper dust cover, making sure its gasket mates with cylinder head properly.

CAUTION: DO NOT rotate crankshaft and cam shaft separately or valves will hit the piston heads.

Page 2.3-5

Installation (Continued)

5. Tighten upper dust cover bolts to 2.9-3.6 foot-pounds

(4-5 N-m) (Figure 45).

6. Instail spark plugs and tighten to 14-22 foot-pounds

(20-29 N-m).

Figure 45A. Engine Cylinder Head Assembiy

Figure 45. Tighten Dust Cover Bolts

Oil pump Spring itopptr *

Oil pump regulator spring . 8# careful of its direction.

Rocker —^0 pivot retainer

<S>

Rocker shaft Be sure to align rocker

shaft front mark to

timing belt side.

Page 2.3-6

Whtn inttalling tliding parti su eh ai bearìngs, ba su re to appiy angina oil on tha iliding lurfacai.

Usa naw gaikati and oil laaii.

Whan inrtallirtg walch plug. apply

saaiant.

Camshaft oil seal '

intake valve insert -

Exhaust valve insert -

Cylinder head gasket

Section 2.4- OIL PAN AND OIL PUMP

Drain engine oil. Then, remove oil pump assembly with oil strainer. BE CAREFUL NOT TO DROP THE OIL PUMP DRIVE SHAFT.

Inspection

Oil Pump Removal

Refer to Part 3, ‘ENGINE LUBRICATION SYSTEM'.

Installation

1. Install the oil pump assembly and tighten to 13-16 foot

pounds (18-22 N-m).

CAUTION: Before tightening the oil pump assem bly, rotate the oil pump drive gear to make sure that the pump drive shaft does not interfere with

inner wall of cylinder block.

2. Apply RTV gasket sealant to oil pan as shown in Figure 47.

3. Install oil seals. Apply RTV sealant to upper and lower surfaces of gaskets as shown (Figure 48).

4. Install gaskets and oil pan. Tighten bolts to 2.9-3.6 foot pounds (4-5 N-m).

__________________________

Figure 47. Apply RTV Gasket Sealant

Apply sealant

Page 2.4-1

Section 2.5- OIL SEAL REPLACEMENT

Camshaft Oil Seal Replacementjpi

Remove timing belot, oil pump idler gear. Remove bolt

stoppers and rocker shaft with rocker arms. Remove cam

shaft. Remove camshaft oil seal. Apply engine oii to new camshaft oil seal and install.

dler

Crankshaft Front Oil Seal Replacement

Remove Timing Belt and Cover. Remove oil pan. Re move main bearing caps. Remove crankshaft oii seai. Appiy engine oil to new crankshaft front oil seal and install.

Page 2.5-1

Section 2.6- ENGINE OVERHAUL

1. Place engine on workstand. Remove timing belt cover and

Disassembly

timing belt Remove cylinder head and oil pan. Remove

pistons.

2. Remove crankshaft rear oil seal retainer. Remove bearing caps. Remove the crankshaft.

RING TO GROOVE SIDE CLEARANCE

MAXIMUM LIMIT

Гор Ring = 0.0016-0.0029 inch (0.040-0.073mm) 2nd Ring = 0.0012-0.0025 inch (0.030-0.063mm)

Maximum

Tolerance=0.008 inch (0.2mrh)

Figure 53. Checking Piston Pin Fit

1. Slide piston pin into piston'pin bore. At room temperature,

Inspection

pin must slide smoothly into bore, without side play and without binding. See Figure 53.

PISTON PIN TO PISTON CLEARANCE

0.0003*0.0005 Inch (0.008-0.012mm)

2. Check piston ring to groove side clearance (Figure 54). Clearance should not exceed the maximum stated limit

TOP RING

No. 1 Grades 0.0083-0.0118 Inch (0.21-0.30mm)

No. 2 Grades 0.0071-0.0118 Inch (0.18-0.30mm) No. 3 Grades 0.0071-0.0118 inch (0.18-0.30mm)

2ND RINGS 0.0059-0.0154 Inch (0.15-0.39mm)

OIL RINGS 0.0079-0.0311 inch (0.20-0.79mm)

4. Use Plastigage" to check bearing clearance (Figure 56). Comply with the following:

Page 2.6-1

Inspection (Continued)

a. DO NOT turn the crankshaft or connecting rod when Plastigage^ is being inserted. b. When bearing clearance exceeds the specified limit, check that the correct bearing has been installed. If exces sive clearance still exists, use a thicker main bearing or an undersize bearing to obtain correct clearance.

BEARING CLEARANCE

Main Bearing= 0.0012-0.0020 Inch (0.03-0.05mm)

Limit = 0.0030 inch (0.075mm)

Connecting

Rod Bearing= 0.0008-0.0024 Inch (0.02-0.06mm)

Limit = 0.0047 inch (0.12mm)

Figure 55. Checking Ring Gap

6. When regrinding crankpin journal, measure the “L° dimen sion in the fillet roll (Figure 58). The measured value must exceed the specified limit. If measurements are within the specified limit, DO NOT regrind.

NOTE: DO NOT grind off the fillet roll. Refer to applicable SPECIFICATIONS chart for regrlndlng crankshaft and available service parts.

5. Inspect crankshaft journals for scoring, bias, wear or cracks. Minor defects can be corrected using fine crocus cloth. Use a micrometer to check journals for taper and out-of-round. See Figure 57.

Out-of-Round (X-Y) = 0.0004 Inch (0.01mm)

Taper (A-B) = Less than 0.0008 inch (0.02mm)

Page 2.6-2

7. Check crankshaft runout. “T.I.R." stands for "Total

Indicator Reading".

8. Surface warpage must be less than 0.004 inch (0.1mm). If beyond the specified limit, resurface the cylinder block. Re

surfacing limit of the cylinder block is determined by the

amount of resurfacing done on the cylinder head. If the amount of resurfacing on the cylinder head is “A" and the resurfacing on the cylinder block is "B‘, the maximum limit is as

I A + B = 0.008 inch (0.2mm) I

CAUTION: When resurfacing, use care not to cut off the punched piston grade number.________________

10. Use a micrometer to measure the piston skirt diameter (Figure 61). The measuring point for checking piston skirt diameter is 0.35 inch (9mm) as shown in Figure 63 (Point “L").

STANDARD PISTON SKIRT DIAMETER

2.6759-2.6770 inch (67.967-67.997mm)

Piston clearance must be within the stated specifica-

tions.

PiSTON CLEARANCE

0.0009-0.0017 inch (0.023-0.043 mm)

9. Use a bore gauge to measure the cylinder bore for wear, taper or out-of-round. Inspect for scratches or seizure. Hone the bore as necessary.

STANDARD INSIDE DIAMETER

2.7953-2.7965 inch (71.00-71.03mm)

OUT-OF-ROUND (X-Y) LIMIT

0.0008 inch (0.02mm)

TAPER (A-B) LIMIT

0.0008 inch (0.02mm)

11. To measure piston clearance, use a 0.0016 inch

(0.04mm) feeler gauge, inserted between the piston and the cylinder bore (Figure 64). The force required to remove the feeler gauge should be as follows:

REMOVAL FORCE

1.1-3.3 pounds (0.5-1.5kg)

12. Check flywheel runout (Figure 65). Total indicator reading

(T.I.R.) should be less than the value specified below.

T.I.R. RUNOUT

Less than 0.0059 inch (0.15mm)

Page 2.6-3

Inspection (Continued)

Each crankshaft has stamped numbers which indicate

main journal dimensions. Each journal is measured sepa

rately.

Select the correct main bearing thickness and order from

the parts breakdown.

Figure 66. Piston Pin Installation

Numbers that correspond to the cylinder number are stamped on connecting rods and connecting rod caps. Pis tons, connecting rods, connecting rod caps and bearings should be installed only in the correct cylinder. DO NOT COMBINE PARTS FROM DIFFERENT CYLINDERS. When pressing the piston pin into the connecting rod (Figure 66), apply oil to the pin and to small end of connecting rod.

CRANKSHAFT:

Place main bearings in their proper position on the cylinder block. If the crankshaft, cylinder block and main bearings are to be replaced, you must select proper main bearing thicknesses.

When either the crankshaft, cylinder block or main bear ings are to be re-used, it is necessary to measure main bearing thickness with Plastigage".

Numbers are stamped on the engine which indicate

cylinder block main journal. Measure each bore separately.

Page 2.6-4

Cylinder Block, Crankshaft and Piston

Apply soaping water to 0-ring.

Apply sealant to threads of and surfaces of gasket.

Water pump suction pipe

Rear oil seal retainer

Crankshaft rear oil seal

Engine rear

rubber

Oil pump drive — shaft

Ring gear

Page 2.6-5

Assembly (Continued)

INSTALL PISTON

1. Install piston rings as shown in Figure 69.

STON ASSEMBLY:

CRANKSHAFT FREE END PLAY

End Play = 0.0024-0.0087 inch (0.06-0.22mm)

Wear Limit = 0.0197 inch (0.50mm)

CONNECTING ROD END PLAY:

Connecting rod end play should be within the following limits;

CONNECTING ROD END PLAY

0.0039-0.0146 inch (0.10-0.37mm)

MAIN BEARING CAPS:

Install main bearing caps and tighten bolts to 34-38 foot

pounds (46-52 N-m). Tighten the caps in 2 or 3 stages and in the sequence shown in Figure 70. Before tightening the bearing cap bolts, place caps in proper position by shifting the crankshaft axially. After tightening the berating cap bolts, check that the crankshaft turns smoothly by hand.

CRANKSHAFT FREE END PLAY:

Measure crankshaft free end play at the center bearing (Figure 71). Nominal end play and wear limit are as follows:

Page 2.6-6

Part 3

ENGINE

LUBRICATION

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

TABLE OF CONTENTS

SECTION

3.1 Lubrication System Familiarization

3.2

TITLE

Engine Oil Pump

AC GENERATORS

Liquid Cooled 1.2 Liter

Gas Engine Models

Section 3.1- LUBRICATION SYSTEM FAMILIARIZATION

Engine Lubrication Circuit

Figure 1, below, shows the engine lubrication circuit in

block diagram form and pictorially.

Use a high quality detergent oil classified "For Service SC, SD, SE or SF". Detergent oils keep the engine cleaner and reduce carbon deposits. Use oil having the viscosity

rating listed in the chart below, based on the ambient temper ature range anticipated before the next oil change.

TEMPERATURE

Above 86' F. 32' to 85* F. Below 32* F. All Seasons

OIL GRADE

Use SAE 40 oil Use SAE 30 oil

Use SAE 20W oil

UseSAE10W-30oll

Low Oil Pressure Shutdown

The engine is equipped with a low oil pressure switch,

which is exposed to oil pressure in the engine's main oil

gallery. The pressure switch contacts are normally-closed (N.C.), but are held open by oil pressure during startup and running conditions. Should oil pressure drop below approxi mately 12-15 psi, the switch contacts will close and an auto matic engine shutdown will occur.

Figure 1. Engine Lubrication Circuit

Recommended Oils

Checking Low Oil Pressure Shutdown

To test the operation of low oil pressure shutdown, start the engine. Let the engine run at no-load, i.e., with all electri cal loads disconnected from the generator. Disconnect wire from oil pressure switch terminal and hold the wire terminal end against a clean frame ground on the engine. After a very short delay, the engine should shut down.

0<i ••»•nr evi'i

■ Bt-mu MM«»

A. Biock Diagram

B. Pictoriai

Page 3.1-1

Warm up the engine. Then, shut down and remove the

Oil Pressure Check

oil pressure switch, install a direct reading pressure gauge in

the oil pressure switch port..,Start the engine and check oil

pressure with the engine running at no-load condition, i.e., no electrical loads connected to generator.

Oil Pressgre reading should be approximately 40-46 psi

(2.8-3.2 kg/cm^) at 1860 rpm.

Page 3.1-2

Section 3.2- ENGINE OIL PUMP

Oil Pump Disassembly

When removing the oil pump, be careful not to drop the oil pump drive shaft. When installing the pump, apply engine oil to the drive gear and shaft. The inner rotor and shaft cannot be disassembled.

Oil Pump Inspection

Visually inspect oil pump parts for wear and damage.

Inspect the oil pressure regulator valve sliding surfaces and valve spring. Replace the valve seat, if damaged. Use a feeler gauge to check (a) rotor tip clearance, (b) outer body to body clearance, and rotor to straight edge clearance. See Figure

Oil Pump Inspection (Continued)

ROTOR TIP CLEARANCE

Less than 0.008 inch (0.2mm)

OUTER ROTOR TO BODY CLEARANCE

Less than 0.008 inch (0.2mm)

ROTOR TO STRAIGHT EDGE CLEARANCE

Less than 0.008 inch (0.2mm)

Page 3.2-2

Part 4

ENGINE

SECTION

4.1

4.2

4.3

FABLE OF CONTENTS

TITLE

Cooling System Familiarization

Water Pump and Thermostat

Cooling and Ventilating Air

COOLING

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERA

TORS

Liquid Cooled 1.2 Liter

Gas Engine Modeis

4.4

4.5 Optional Heat Recovery System

Optionai Remote Radiator Fan

Section 4.1- COOLING SYSTEM FAMILIARIZATION

The generator cooling system is of the closed recovery

Introduction

type. Major cooling system components consist of (a) radia tor, (b) coolino fan, (c) coolant recovery bottle, (d) engine

water pump, (e) thermostat, and (f) interconnecting hoses.

Recreational vehicle generators are typically housed in

a compartment. An adequate flow of cooling, combustion and

ventilating air must be provided for these compartments.

Some models are equipped with unit-mounted radiators.

Other models may have remote mounted radiators.

At least one IM (Industrial Mobile) generator model is

equipped with a heat recovery system.

Recommended Coolant

Recommended Is a 50-50 mixture of low silicate ethylene glycol base anti-freeze and soft water for all-weather protec tion. If desired, a high quality rust inhibitor may be added to the recommended mixture. When adding coolant to the radi

ator or to the coolant r4ecovery bottle, always add the recom mended 50-50 mixture.

NOTE: Cooling system capacity for models with unitmounted radiator Is approximately 2.5 U.S. gallons (9.5 liters). Use only SOFT water and LOW SILICATE anti freeze. For Installations equipped with a remote-mounted radiator, cooling system capacity will depend on radiator hose lengths.

CAUTION: The use of any "chromate" base Inhib itor is NOT recommended. When chromate base rust inhibitor is used with ethylene glycol base anti-freeze, chromium hydroxide Is formed in the cooling system. Chromium hydroxide Is visible to the eye as a "green slime" which can cause re duced heat transfer and possible overheating. Any cooling system that has been operated with a chromate base inhibitor must be chemically cleaned before adding ethylene glycol base anti freeze. Use of any high silicate anti-freeze boost ers or additives is NOT recommended. In addition to the preceding, the use of any soluble oil rust inhibitor Is NOT recommended.

The switch contacts should close and switch should read

“continuity“ at about 225‘-235’ F. (107'-113‘ C.).

High Coolant Temperature Switch

DESCRIPTION:

The engine mounts a normally-open (N.O.) thermostatic

switch (Figure 1). The sensing tip of the switch is normally

immersed in engine water jacket coolant. Should coolant temperature exceed approximately 230' F. (110* C.), the switch contacts will close and the engine will shut down automatically.

TESTING HIGH TEMPERATURE SHUTDOWN:

To test the high temperature shutdown feature, first disconnect Wire No. 85 from the switch terminal. Start the engine, let it stabilize and warm up at no-load. Hold the terminal end of Wire No. 85 into contact with a clean frame ground on the engine. After a short delay, the engine should shut down.

TESTING THE SWITCH:

Remove the switch. Check the switch closing tempera

ture with an ohmmeter (Figure 2).

Page 4,1-1

Section 4.2- WATER PUMP AND THERMOSTAT

The engine water pump (Figure 3) cannot be disassem-

Water Pump

bied and must be replaced as a unit. Check the [pump for

excessive end play and smoothness of rotation. Bolt holes are drilled through the water jacket in the cylinder block. Use a sealant and tighten the bolts to the recommended torque. After installation, operate the engine and check for leaks.

Thermostat

Check the thermostat for proper seating at ambient tem perature. It should seat tightly. Check its opening tempertature and lift.

VALVE OPENING TEMPERATURE

190* F. (88* C.)

MAXIMUM VALVE LIFT

0.31 Inch at 212’ F. (8mm at 100* C.)

Figure 5. Testing the Thermostat

After installing the thermostat, run the engine and check

for leaks.

Figure 3. Engine Water Pump

■ Water pump assembly

Page 4.2-1

Section 4.3- COOLING AND VENTILATING AIR

Service technicians sho work on the Series NP (recrea

tional vehicle) and IM (industrial mobile) generators should

be familiar with air flow requirements for these units. Ade quate air flow for cooling, ventilation and combustion MUST be provided or serious problems will result.

Types of Cooling Fans

General

Engine-generators may be equipped with either (a) a PUSHER type fan, or (b) a SUCTION type fan. The suction type fan used on some models is a 'squirrel cage" fan.

Air Flotw- Pusher Fan Units

See Figure 6. A blower fan, attached to the generator Rotor, draws air into the generator interior to cool generator internal parts. The heated generator air is expelled through a blower air outlet duct on the side of the unit. The engine's "pusher“ type cooling fan draws air around the unit, then

forces the air through the radiator, outward and away from the unit.

Air Flow- Suction Fan Units

Generator internal parts are cooled in the same manner as for "pusher" fan units. The suction type engine cooling fan is a high capacity, squirrel cage type. The fan draws air in and

across the radiator, then directs the air downward and away from the unit through an air duct. See Figure 7.

Additional information on cooling and ventilating require

Installation Manual

ments can be found in the "INSTALLATION MANUAL" for

water-cooled RV generators. These manuals can be ordered from Generac Corporation.

Figure 7. Typical Installation- Unit with Suction Type Fan

-----

■« j

----;---------

□

Page 4.3-1

Section 4.4- OPTIONAL REMOTE RADIATOR FAN

Some NP senes engine-generators are not equipped

with a unit-mounted radiator. The radiator on such units is

mounted at a remote location in the vehicle that houses the generator. Such installations might require the following options:

An electrically operated RADIATOR FAN, along with a

temperature sensor switch.

A squirrel cage type COMPARTMENT FAN which draws

cooling and ventilating air through the compartment housing

the generator.

Compartment Fan

The compartment fan (Figure 8) must be properly lo cated during installation. When running, it must draw cooling and ventilating air through the generator compartment and expel the air to the outdoors. The compartment fan is needed, since an engine-driven fan Is not provided.

The compartment fan motor is connected to generator

AC output leads 11 and 22. When the generator is running and AC voltage is available, the fan will operate.

A Remote Radiator Assembly

COMPONENTS:

Major components of a typical remote radiator and fan include (a) the radiator, (b) the fan, (c) a thermostatic switch, (d) mounting hardware, and (e) wiring harnesses. See Figure 10 on next page.

OPERATION:

See Figure 9, below. Battery voltage for fan operation is always available to Tewrminal 30 of the Fan Relay (SR), via a 14 amp fuse and Wire 13A. However, the fan relay normallyopen contacts are open and the fan Is NOT running. On cranking and startup of the generator, an engine control circuit board delivers 12 volts DC to the Thermostatic Switch (TS) via Wire 14, Relay Coil, and Wire 243. If coolant temper ature is below approximately 180' F., the thermostatic switch contacts will be open. As soon as coolant temperature In creases above 180' F., the switch contacts close and Wire

243 is grounded. Fan Relay (SR) then energizes, its normally-

open contacts close, and DC voltage is delivered to the FAN

via Wire 244. The fan is now powered and will run.

^ 244

.244 .

Figure 9. Remote Radiator Fan Operating Diagram

i)tt

NOTE: ThermottaUc switch contacts close above 2^3

FAN RELAY

■ 13A .

^80" F.; fan relay contacts are energised closed

when switch contacts close.

12VDC WITH

- 14——

14 AMP

FUSE

ENGINE RUNNING

"only

,12 VDC FAN

POWER SUPPLY

THERMOSTATIC

7777777

Page 4.4-1

ITEM QTY

1 1 2 3 4 1 Remote Fan Harness 5 4 Fan to Radiator Brackets 14 6 1 7 4 M5-0.80 X 10mm Capscrew 16 8 9 4

1 Radiator Fan

4 Fan Mounting Bracket 12 4 M6 Hex Nut

4 MS Lockwasher 17

DESCRIPTION

Radiator Assembly

Radiator Cap

M5-1.00 X 12mm Capscrew

ITEM QTY

wM^.

■

Page 4.4-2

DESCRIPTION 10 4 11 4

13 1 15 4 In. Flex-Gard

6.5 in.

—

M6 Flatwasher

M6 Lockwasher M6 Star Washer

Tie Wrap

Flex-Gard

Pipe Sealant

Thermostatic Switch

Section 4.5- OPTIONAL HEAT RECOVERY SYSTEM

Some IM (Industrial Mobile) engine-generators are

General

equipped with a heat recovery system. If desired, the cus tomer can use this system to provide heated air while working in cold areas (such as a manhole).

Operation

Figure 1, below, is a schematic diagram of a heat recov ery system. Factory Installed components include (a) a heat exchanger, fb) a control valve, (c) a thermostat, (d) the engine radiator, and (e) interconnecting hoses and fittings. Operation may be briefly described as follows;

1. Coolant from the engine flows through the heat exchanger where it is heated by the engine exhaust, which also passes through the heat exchanger.

2. From the heat exchanger, coolant flows to a control valve

(CV). The control valve can be positioned manually, as fol

lows:

a. It can be actuated manually to direct coolant through a customer-supplied remote heater and then to a thermostat housing (TH).

b. It can be actuated manually to direct coolant to the thermostat housing (TH) and not to the customer’s remote heater.

3. The thermostat (TH) either delivers the coolant back to the engine or to the unit radiator, as follows:

a. If coolant temperature Is less than 192’ F. (89’ C.), additional cooling is not needed, and the coolant Is deliv ered back to the engine.

b. If coolant temperature is greater than 192’ F. (89’ C.), additional cooling is needed, and the coolant is delivered to the unit radiator and then back to the engine.

This heater is usually supplied by the user, in conjunction with a fan or blower to extract the heat from the remote heater and deliver it to the desired work area(s). The user must ensure that the entire system has been properly filled with the

recommended coolant mixture prior to use.

Exploded View of Heat Recovery System

Customer Remote Heater

system. Parts included in the drawing are iisted below.

ITEM DESCRIPTION

1 Exhaust Manifold 2 End Plate 3 Thermostat Hsng. 4 Thermostat 5 Gasket

6 Water Pump

7 Lockwasher

8 Hex Nut

9 Stud

10 Fitting

12 Pipe Plug

13 Gasket

14 Gasket

15 Gasket

16 Fitting

17 90* Fitting

18 Brass Fitting

19 Gasket

Figure 12 (next page) shows a typical heat recovery

ITEM DESCRIPTION

20 Filler Neck 21 Radiator Cap 22 Exhaust Flange 23 Hose Clamp 24 Upper Hose 25 Lower Hose 26 Hose 27 Hose 28 Hose 29 Stud 30 Stud 31 Stud 32 Pipe Plug 34 Hose 35 Fitting 36 Hose Clamp 37 Lifting Lug 38 Lockwasher

Figure 11. Schematic Diagram- Engine Cooling and Heat Exchanger System

Page 4.5-1

Figure 12. Exploded View of Heat Recovery System

Page 4.5-2

Part 5

GASOLINE

FUEL

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

5.1

5.2

5.3

TITLE

General information

Fuel Pump

Carburetor

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasollne Engine Models

Section 5.1- GENERAL INFORMATION

Any high quality LEADED or UNLEADED regular grade

iasoline having a minimum posted octane number of 86

research octane number 90) is satisfactory for use with RV

and IM generators.

Use of any gasoline containing alcohol (either methanol or ethanol) Is NOT RECOMMENDED. Gasolines containing alcohol tend to absorb moisture from the air. Such absorption causes the water and alcohol to separate from the gasoline in the fuel tank. The adverse affects of alcohol increase in severity with methyl alcohol (methanol). In addition, the ad

verse affects worsen with increasing alcohol content. Use of

gasoline containing alcohol may result in one or more of the

following:

D Corrosion of metal parts.

Fuel Recommendations

CD Deterioration of elastomer and plastic parts,

n Fuel permeation through flexible fuel lines. D Wear and damage of internal engine parts.

D Starting and operating difficulties.

If the use of gasoline containing alcohol cannot be avoided, do not store the gasoiine in fuel tank for long periods of time. Long periods of fuel storage create unique problems.

Fuel System Components

Major gasoline fuel system components include (at a fuel pump, (b) the carburetor, and (c) interconnecting fuel lines. See Figure 1.

When the engine is cranked and started, the 12 volts DC electric fuel pump is turned ON. At the same time, a solenoid actuated fuel shutoff valve on the carburetor is opened to allow fuel flow to the caiburetor.

The carburetor mounts an automatic electric choke which closes the carburetor choke valve while the engine is being cranked.

Carburetor throttle valve setting is established by the action of a constant speed governor. Most generator models utilize a mechanical, flyweight type governor. Some models, however, may be equipped with an electronic governor.

Page 5.1-1

Section 5.2- FUEL PUMP

The fuel pump Is energized ON during cranking and

General

running when an engine controller circuit board delivers 12

volts DC power to a Wire No. 14 circuit. Circuit board action

also energizes (a) a fuel solenoid, (b) a choke heater, and (c)

the engine ignition system.

Testing the Fuel Pump

Use an ohmmeter or a volt-ohm-mllliammeter (VOM) to

test the pump windings for continuity.

To perform an operational test of the pump, disconnect fuel line from the punp outlet side and connect pump inlet side to a fuel supply. Connect a +12 volts DC power supply (such as a battery) to the pump WHITE wire and a -12volts DC power to the pump’s BLACK wire. The pump should operate and pump fuel. Replace pump. If defective.

Figure 2. Eiectric Fuel Pump

Page 5.2-1

Section 5.3- CARBURETOR

Remove carburetor air intake components as necessary to gain access to the carburetor. Disconnect the carburetorgovernor link. Disconnect fuel line. Remove carburetor, car buretor adapter and gaskets.

Disassembly

Removal

See Figure 5 on next page. Disassemble the carburetor as follows:

1. Remove two screws and lockwashers, then remove FUEL INLET PLATE and GASKET.

2. Remove two screws and washerts, then remove CHOKE SOLENOID ASSY.

3. Remove four screws and washers, then remove FLOAT BOWL COVER along with FLOAT BOWL GASKET, FLOAT, FLOAT SHAFT, SPfflNG, FUEL VALVE AND SEAT ASSY.

4. Remove FLOAT SHAFT, SPRING, FUEL VALVE and FLOAT.

5. Remove FLOAT BOWL GASKET.

6. Remove SEAT ASSY.

7. Remove two CHOKE PLATE SCREWS, then remove CHOKE PLATE.

8. If necessary for replacement, remove FUEL SOLENOID and seal.

9. Remove IDLE ADJUSTING NEEDLE & SPRING.

10. Clean all parts in clean gasoline.

Reassembly

Reassemble all parts in the reverse order of disassem bly. During the reassembly process, install new parts from carburetor repair kit. Pay close attention to the following:

D Open throttle plate slightly for idle speed. D Set the Idle adjusting needle 3/4 turn open.

With float bowl cover inverted and float bowl gasket installed, set float level 0.125 inch (3.175mm) from the float bowl gasket (see Figure 1).

Tighten air intake mounting screws. Make sure the throt

tle shaft rotates freely. Tighten the FUEL SOLENOID to 70

inch-pounds.

Insert short leg of CHOKE SHAFT SPRING into small hole in CHOKE SHAFT (Figure 2). Wind SPRING 1-1/2 turns

counterclockwise, anchor on retaining screw boss.

Install casket, adapter, gasket and carburetor. Retain

Installation

with socket head machine screws.

Automatic Choke Adjustment

Loosen CHOKE SOLENOID adjusting screws and adjust

choke position so that, with the solenoid pulled in (energized),

the choke piate is closed. With choke plate closed, tighten the

adjusting screws. Then, with solenoid extended, bend tip of

the bi-metal until choke plate is about 1/8 inch from vertical

and towards the closed position.

Page 5.3-2

Part 6

SECTION

6.1

TITLE

Introduction to Gaseous Fuel

Systems

GASEOUS

FUEL

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Models

6.2

6.3

Major Components- Liquid

Withdrawal System

Major Components- Vapor

Withdrawal System

Section 6.1- INTRO. TO GASEOUS FUEL SYSTEMS

Some NP/IM series engine-generators may be equif^ed

General

with optional LP (liquefied petroleum) gas fuel systems. This fuel is supplied as a liquid in pressure tanks.

LP gas is usually made up of (a) propane, (b) butane, or

converted to its vapor state before it enters the engine carbu

retor. Propane will vaporize at temperatures as low as 20' F.

(-6.7‘ C.). Butane exists in its liquid state when temperatures drop below 32' F. (O’ C.). In colder weather, fuel suppliers will usually increase the amount of propane in the fuel mixture for better vaporization. Under extremely cold conditions, butane gas may not provide sufficient vapor pressure to operate the engine.

Q One gallon of butane liquid equals about 31.26 cubic feet

of butane gas.

EH One gallon of propane equals about 36.39 cubic feet of

propane gas.

Vapor Withdrawal System

The LP gas fuel system may be either (a) a vapor

withdrawal system or (b) a liquid withdrawal system.

The vapor withdrawal system utilizes the vapors that form above the liquid fuel in the supply tank. One typical vapor withdrawal supply tank is shown in Figure 1.

The vapor withdrawal system, because it uses qaseous fuel vapors. Is much like a natural gas system. See Figure 2. The fuel vapors are delivered to a customer-supplied primary regulator which reduces the gas vapor pressure. The gas then goes to a fuel lockoff solenoid. Optimum gaseous pres sure at the inlet to the fuel lockoff solenoid is about 11 inches (water column) and not to exceed 14 inches (water column). The function of the primary regulator is to provide this opti mum fuel pressure to the solenoid. From the fuel lockoff solenoid, the gaseous fuel is delivered to the inlet of a pressure reducer valve. The pressure reducervalve receives the gas at the stated optimum pressure, reduces the gas pressure to a negative (vacuum) pressure of about -1 inch (water column). The gas is then delivered to the carburetor which meters the gas to the engine based on engine demand.

Figure 1. Typical Vapor Withdrawal Supply Tank

Liquid Withdrawai System

A typical liquid withdrawal fuel supply tank is shown in

Figure 3 (next page). A pickup tube extends down into the tank. Vapor pressure on top of the fuel in the tank forces the fuel to flow through the pickup tube and to the engine-gener ator fuel system.

A typical liquid withdrawal type fuel system is shown in

Figure 4 on the next page. From the fuel supply tank, liquid fuel flows to a fuel lockoff solenoid on the generator. The liquid fuel Is then delivered to a vaporizer-regulator. Heated engine coolant also flows through the vaporizer-regulator, to heat the fuel and change it to its vapor state. The vaporized fuel is then delivered to the engine carburetor at greatly reduced pressure.

11 In. H20 OPTIMUM

? FROM SUPPLY TANK

PRIMARY REGULATOR

Figure 2. A Typical Vapor Withdrawal System

SECONDARY REGULATOR

FUEL SHUTOFF VALVE

r CARBURETOR-

Page 6.1-1

As the throttle is opened wider, air flow increases through the carburetor venturi and the vacuum at the venturi throat Increases proportionally. Diaphragm movement increases, the regulator metering valve opens further, and gas flow to the carburetor increases.

The following facts apply to venturi type gas carburetion

systems:

n The regulator must be properly adjusted so that it will

stop the flow of gas when the engine is not running.

D The slightest vacuum should lift the regulator metering

valve off its seat and allow gas flow to the engine.

D If diaphragm spring force is excessive, too much vacuum

will be needed to open the regulator metering valve. This

will result in a flat spot or sluggish progression off idle. Lean mixtures and power loss at full loao may also result.

D If diaphragm spring force is too weak, fuel leakage after

shutdown may result. Hard starting and the danger of fire exist.

See Figure 5. During the engine Intake stroke, air is

Gas Carburation

drawn into the engine. This air flows through a venturi in the carburetor and creates a vacuum at the venturi throat. The

amount of vacuum created is proportional to the amount of air flow. That is, the greater the air flow through the venturi, the greater the amount of vacuum.

The vacuum created at the carburetor venturi throat acts on a diaphragm in the vaporizer-regulator (liquid withdrawal system) or pressure reducer valve (vapor withdrawal), to pull the diaphragm toward the source of vacuum. Diaphragm

movement opens a metering valve and allows gas to flow to

the carburetor.

DANGER: GASEOUS FUEL REGULATORS MUST

BE PROPERLY ADJUSTED AND TESTED AT THE

TIME OF INSTALLATION, TO PREVENT GAS

LEAKAGE AND POSSIBLE FIRE OR EXPLOSION. INSTALLATION, ADJUSTMENT AND TESTING

SHOULD BE ACCOMPLISHED ONLY BY QUALI

FIED GAS SERVICE TECHNICIANS. THE GAS FUEL SYSTEM MUST COMPLY WITH ANSI

119.2/NFPA 501C, CHAPTER 2, “FUEL SYSTEMS AND EQUIPMENT". FOLLOWING INSTALLATION THE SYSTEM MUST BE PROPERLY PURGED AND LEAK TESTED. NO LEAKAGE IS PERMISSIBLE.

LP Gas Conversion Kit

An LP gas conversion kit is available for installation on

NP and IM generators with 1.2 liter gas engine. Installation of thé proper conversion kit will allow LP gas to be used as a fuel. The Model 9251 kit is a vapor withdrawal type; Model 9052 is a liquid withdrawal type. The kits do not include fuel supply tanks, nor do they include fittings, lines, etc., required to store the fuel and deliver the fuel to the fuel lockoff solenoid.

Instructions are included with the kit. To order instructions only, specify manual Part No. 78360.

A primary regulator Is required for vapor withdrawal

systems. That regulator is not included in the kit.

Page 6.1-2

Section 6.2- LIQUID WITHDRAWAL SYSTEMS

Figure 8 (next page) is an Exploded View of a typical

Introduction

LIQUID WITHDRAWAL type gaseous fuel system. Major

components of the system include the following:

D Fuel Solenoid Assembly,

n Vaporizer-Regulator Assembly, n Carburetor Assembly.

D Air Cleaner Assembly,

n Interconnecting lines and fittings.

Fuel Solenoid Assembly

See Item 12, Figure 8. The electrically actuated fuel solenoid is energized open, de-energized closed. Mainte nance on this part Is generally limited to replacement of the entire solenoid assembly.

NOTE: If the fuel solenoid assembly must be replaced,

use only an assembly that Is useable with a liquid with

drawal system. Fuel solenoids are not Interchangeable between liquid and vapor withdrawal systems. Fuel solenoids used on liquid withdrawal systems must be rated at a much higher pressure than vapor withdrawal solenoids.

Vaporizer-Regulator Assembly

The vaporizer-regulator included with the Model 9052 LP gas conversion kit is an IMPCO Model JB. The vaporizer-reg

ulator must perform the following functions:

Carburetor Assembly

DESCRIPTION:

The carburetor assembly included with the Model 9052 gas conversion kit is an IMPCO Model CA50-506. See Figure 7.

Vaporizer-regulator and carburetor operation are de scribed under "GAS (^ARBURETION" on Page 6.1-2.

The carburetor is equipped with (a) an idle mixture ad justment, and (b) a load adjustment.

n It must positively stop the flow of gas when the engine is

not running.

D At the slightest vacuum, the regulator metering valve

must move off its seat and allow gas flow to the engine,

n Heated engine coolant, passing through the vaporizer-

regulator, must vaporize the liquid fuel before it reaches the carburetor.

See Figure 6. Engine coolant lines connect to the vapor

izer-regulator, as well as inlet and outlet lines for LP gas.

Figure 6. Vaporizer-Regulator

ADJUSTMENTS:

Idle Mixture: This adjustment affects fuel-air mixture only when the engine is running at idle speed. It has no affect on operation at the engine’s normal rated speed of approxi mately 1800 rpm and, for that reason, adjustment is not required. However, if you wish to adjust idle mixture, proceed as follows:

1. Connect an AC frequency meter to the generator’s AC power output leads.

2. Disconnect all electrical loads from the generator.

3. Start the engine, let it stabilize and warm up at no-load.

4. Reduce engine speed until frequency meter reads approx imately 30-33 Hertz.

5. Slowly turn the idle mixture screw clockwise until engine starts to run rough. Then, turn the screw counterclockwise until engine again starts to run rough. Finally, turn the screw clockwise until smooth operation is obtained.

Load Adjustment: This is an adjustment of fuel-air mixture with the rated load of the unit applied. Complete the adjustment as follows:

1. Connect an AC frequency meter to the generator’s AC

power output leads.

2. Disconnect all electrical loads. This can be done by setting the main circuit breaker to "Off“ or "Open".

3. See Figure 9. Turn the load adjustment as far as it will go toward the "R" (maximum rich).

4. Start the engine, let it stabilize and warm up at no-load.

Page 6.2-1

Parts List for Liquid Withdrawal Fuel System

ITEM QTY

1 2 1 3 4 5 1 6 7 8 9 1

10 2

11 1

14 1

NOTE 1: Carburetor adapter shown is for units with mechanical governor.

Page 6.2-2

1 1

1 2

3/8" NPT X 1/2" Barbed 90’ Fitting 20 1

Carburetor Adapter (See Note 1) 24 1

5/16"-18 X 1" Socket Head Capscrew

3/8" NPT X 5/8" 90* Barbed Fitting 28 2

DESCRIPTION ITEM QTY

Air Cleaner Stud 16

Air Cleaner Cover 17

Air Cleaner Element

Air Cleaner Adapter 19 1

Carburetor Assembly

M8-1.25 X 65mm Capscrew 22 1

Carburetor Gasket 23 1

1" to 3/8" Reducer 26 2

Fuel Solenoid Assembly

LP Gas Fuel Line 29

LP Gas Vaporizer-Regulator

25 2 27 2

30 2

DESCRIPTION 1 1

1/4" NPT Brass Elbow

Ventilation Hose

" NPT X 1-1/2" long Pipe Nipple

3/8

Solenoid Mounting Bracket

M8-1.25 X 50mm Capscrew

1/4" NPT 90’ Fitting (Brass)

M6-1.00 X 25mm Capscrew

Hose Clamp

5/8" IDxll" long Hose 5/8" ID X 20" long Hose

M6 Flatwasher

M6 Lockwasher

M6 Nut

1/2" NPT X 5/8" 90* Elbow

M8 Lockwasher

Carburetor Assembly (Continued)

ADJUSTMENTS (CONTINUED):

5. Apply an electrical load to the unit equal to the generator’s rated maximum continuous wattage/amperage capacity.

6. Slowiy turn the load adjustment toward the ’L" (leaner) until

the engine starts to run rough and frequency meter reading starts to decrease.

7. Slowly turn the load adjustment back toward "R" (richer)

until engine starts to run rough and frequency meter reading again starts to decrease.

8. Turn the load adjustment toward the "L" (leaner) until

smooth operation and highest frequency is obtained.

9. Turn off all electrical loads and check frequency reading.

The no-load frequency should be 60.5-63.5 Hertz for 60 Hertz

units; or 49-52 Hertz for 50 Hertz units.

NOTE: If the no-load frequency reading Is Incorrect, adjustment of the engine governor may be required. See Part 7, "ENGINE SPEED CONTROL SYSTEM".

Page 6.2-3

Section 6.3- VAPOR WITHDRAWAL SYSTEM

Figure 10 (below) is an Exploded View of a typical

Introduction

VAPOR WITHDRAWAL type gaseous fuel system. Major

components include the following;

D Fuel Solenoid Assembly.

CH Pressure Reducer Valve. D Carburetor Assembly.

D Air Cleaner. n Interconnecting lines and fittings.

The electrically actuated fuel solenoid is energized open,

Fuel Solenoid Assembly

de-energized closed. Maintenance is generally limited to replacement of the solenoid assembly. When replacing the solenoid be sure to use the correct one for the system. Solenoids are not interchangeable between liquid and vapor withdrawal systems.

The solenoid is energized open by 12 volts DC during cranking and running. On shutdown, the solenoid must pos itively close to stop the flow of gas through the system.

Parts List for Vapor Withdrawal Fuel System

ITEM QTY

1 2 1 3 4

6 7 8 9

10 2

11 1

NOTE: Carburetor adapter shown Is for units with mechanical engine governor.

1 1

1 1 2 1

3/8“ NPT X 1/2“ Barbed Fitting (90‘)

5/16’’-18 X 1 ” Socket Head Capscrew

DESCRIPTION

Air Cleaner Stud

Air Cleaner Cover

Air Cleaner Element

Air Cleaner Adapter

Carburetor Assembly

M8-1.25 X 65mm Capscrew

Carburetor Gasket

Carburetor Adapter (NOTE 1)

3/4" to 3/8" Reducer

ITEM QTY

12 13 14 15 16 17 18 19 20 21 22 2

DESCRIPTION

2 1 1 1 1

2 1 1 1

Fuel Solenoid Assembly

3/4“ NPT X 5/8” 90* Barbed Fitting

5/8" ID X 18-3/4“ long Hose

Pressure Reducer Valve

3/4" NPT Nipple Ventilation Hose

Hose Clamp

3/8“ NPT X 1“ long Pipe Nipple

Solenoid Bracket

M8-1.25 X 50mm Capscrew

M8 Lockwasher

Page 6.3-1

The pressure reducer valve used in the Model 9251 LP

Pressure Reducer Valve

gas conversion kit is an IMPCO Model IMP-52. LP gas, in vapor form, is delivered to the valve inlet at approximately 11 inches (water column). Valve inlet pressure should not ex ceed 14 inches (water column). The pressure reducer valve provides a regulated pressure decrease down to approxi mately minus 1 inch (water column) and delivers this reduced (vacuum) pressure to the carburetor.

The pressure reducer valve is designed for both natural

nd LP gas fuel systems. For LP gas vapor withdrawal

applications, it must be modified as follows (Figure 12):

•

1. Remove END CAP.

2. Remove ITEMS B and A.

3. Install and tighten END CAP.

4. Install the valve In the position shown (spring neck down).

The Models 9052 liquid withdrawal system and the Model

Carburetor Assembly

9251 vapor withdrawal system both utilize an IMPCO CA50506 carburetor. Refer to ’CARBURETOR ASSEMBLY’ on Pages 6.2-1, 6.2-2 and 6.2-3.

Page 6.3-2

Part 7

ENGINE

SPEED

CONTROL

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

7.1

7.2

TITLE

Mechanical Governor

Electronic Governor

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Models

Section 7.1- MECHANICAL GOVERNOR

The mechanical engine governor utilizes the principle of

General Description

spring tension versus centrifugal force to maintain a steady state engine speed, regardless of the applied load. When centrifugal flyweight force exceeds governor spring tension, the flyweights act on a yoke to rotate a rocker shaft. Rocker shaft rotation decreases carburetor throttle setting and en gine speed decreases. As engine speed decreases, governor spring tension becomes greater than flyweight centrifugal force. The spring then increases carburetor throttle setting and engine speed increases. The governed speed is that

rpm at which flyweight force and spring force are equal.

The governor flyweights are driven by an engine v-belt. The pulley which drives the flyweights also dnves a DC alternator assembly, used to maintain battery state of charge during engine operation.

Figure 1. Mechanical Engine Governor

Reassemble the DC alternator in the reverse order of re moval. Install socket head screws that retain the stator and tighten them to 5 foot-pounds (7 N-m). Tighten the hex jam nut to 35 foot-pounds (47 N-m).

Governor Lubrication

See Figure 2. To fill the governor with oil, proceed as

follows:

1. Remove OIL FILLER PLUG and OIL LEVEL CHECK

PLUG,

2. Add engine oil through FILLER PLUG until oil just starts to overflow the OIL LEVEL CHECK PLUG opening. Pour slowly.

3. When oil level is correct, install and tighten OIL FILLER and OIL LEVEL CHECK PLUGS.

Maintenance and repair of the governor is limited to the

Governor Maintenance

following;

n Removal and replacement of the DC alternator assem-

bly.

□ Removal and replacement of governor lever, links and

springs.

D Removal, replacement and adjustment of governor to

carburetor linkage.

CH Adjustment of governed speed.

dC Alternator Removal

Refer to Figure 4 on next page. Remove the DC alterna

tor assembly as follows:

1. Remove hex jam nut (Item 43), wave washer (Item 48), and

pulley half (Item 44).

2. Remove the DC alternator Rotor (Item 44).

3. Remove socket head screws (Item 35) and lockwashers (Item 22).

4. Remove the Stator (Item 47).

1. Connect an AC frequency meter across the generator’s AC

Engine Governor Adjustment

output leads.

2. Turn OFF all electrical loads. Initial adjustments will be accomplished at no-load.

3. Start the engine, let it stabilize and warm up.

4. Check the no-load AC frequency. Readings should be as follows:

Units Rated at 60 Hertz = 60.5-63.5 Hertz

Units Rated 50 Hertz = 49-51 Hertz

5. No-Load Governed Speed Adjustment: If adjustment of no-load governed speed is required, proceed as follows (see Figure 3):

a. Loosen the NO-LOAD BUMPER SCREW lock nut, then loosen the NO-LOAD BUMPER SCREW so the governor is not pre-loaded.

b. Adjust the NO-LOAD SPEED ADJUST SCREW to ob tain a frequency reading as close as possible to 61.5 Hertz for units rated 60 Hertz; or to 50.0 Hertz for units rated 50

Hertz. c. Adjust the NO-LOAD BUMPER SCREW to obtain a

frequency of 62 Hertz (60 Hertz units); or 51 Hertz (50 hertz

units).

6. Adjustment Under Load: Apply an electrical load to the generator equal to the rated wattage/amperage capacity of the generator. Then, proceed as follows:

Page 7.1-1

Figure 4. Exploded View of Governor-DC Alternator Assembly

ITEM

3 4

13 14

16 17 18 19

23 25 26 27 28

DESCRIPTION

Governor Housing

0-Rlng Seal

Governor Flange

Drive Shaft Assembly

Ball Bearing

Oil Seal

Ball Bearing

Truss Head Screw

Flyweight Flyweight

Dowel Pin

External Retaining Ring

Thrust Sleeve

Needle Bearing

Thrust Washer Thrust Washer

Roll Pin

External Retaining Ring

Inner Ring Bushing

Bearing Draw Cup

M4-0.70 Hex Screw

M4 Lockwasher

Yoke

Rocker Shaft

Oil Seal

Ball Bearing

Externai Retaining Ring

ITEM

29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53

54 55

DESCRIPTION

M6-1.00 Hex Screw

M6 Lockwasher

Tension Bracket

Tension Bracket Bushing

M6-i.00 Hex Screw

Sealing Washer

M4-0.70 SWocket Head Capscrew

M6-1.00 Hex Screw

M6-1.00 Nut

Bumper Screw

Compression Spring

1/8“ NPT Pipe Plug

Spacer

Pulley Half

Hex Jam Nut

DC Alternator

Cable Clamp

M4-0.70 Pan Head Screw

DC Stator Assembly

Wave Washer

Tension Spring

M6-1.00 Hex Nut

M6-1.00 Screw

Governor Lever

Governor-Carburetor Link

Ball Joint

No. 10-32 Flanged Lock Nut

Page 7.1-2

Engine Governor Adjustment (Continued)

a. Check the AC frequency reading under load. b. If frequency drops below about 58 Hertz (60 Hertz units)

or 49 Hertz (50 Hertz units) under load, adjust the DROOP ADJUSTMENT downward until application of the load

results in the smallest possible AC frequency droop when maximum load is applied.

NOTE: If surging occurs when electrical load Is removed, adjust the NO-LOAD BUMPER SCREW Inward. If BUMPER SCREW adjustment changes the AC frequency reading, back the NO-LOAD BUMPER SCREW out until no-load frequency returns to 62 Hertz (60 Hertz units); or

to 51 Hertz (50 Hertz units). NOTE: With unit running at correct AC frequency, you

may wish to check the generator’s AC output voltage. If

frequency reading Is correct, but voltage reading Is In correct, adjustment of the AC voltage regulator may be required.

Figure 3. Governor Adjustment Points

Page 7.1-3

Section 7.2- ELECTRONIC GOVERNOR

Some industrial mobile (IM) series generators may be

General

equipped with an electronic engine governor system. The system consists of the following major components:

n A 12 volts DC Governor Actuator Relay (GAR).

■ n An Electronic Governor Actuator (EGA), n An Electronic Governmor Control circuit board (EGC). n A Magnetic Pickup assembly (MPU). n Interconnecting wiring.

Figure 4 is an operating diagram of the electronic gover

nor system. Operation may be briefly described as follows:

1. During engine startup and running, an Engine Control circuit board delivers 12 volts DC to a GOVERNOR ACTUA TOR RELAY (GAR) via Wire No. 14. The Relay energizes and its normally-open contacts close.

2. When the Relay contacts close, 12 volts DC is delivered to the ELECTRONIC GOVERNOR CONTROL (EGC) circuit board, to turn the governor system on.

3. Engine speed information is delivered to the ELECTRONIC GOVERNOR CONTROL (EGC) circuit board from a MAG

NETIC PICKUP (MPU). This “actual* speed is electronically compared to a "reference” speed that has been preset on the circuit board.

4. If any difference exists between “actual" and "reference"

speed, the ELECTRONIC GOVERNOR CONTROL (EGC) board sends speed correction signals to an ELECTRONIC GOVERNOR ACTUATOR (EGA).

5. The ELECTRONIC GOVERNOR ACTUATOR (EGA) is

mechanically linked to the carburetor throttle valve.

Figure 4. Governor System Schematic

energize and normally-open Relay contacts 4 and 7 should

actuate closed.

With the Relay coil energized, a VOM connected across

Relay Terminals 4 and 7 should read “continuity“.

With the Relay coil de-energized, a VOM connected

across Relay Terminals 4 and 7 should read "infinity".

Figure 5. Governor Actuator Relay

COIL

NORMALLY-OPEN

CONTACTS

NORMALLY-CLOSED. CONTACTS

A. Schematic

ysj -nr

B. Pictorial

Governor Actuator Adjustment

With the engine shut down, adjust the length of the Electronic Governor Actuator (EGA). With the carburetor throttle valve closed, adjust so that approximately 0.40-0.78 inch (1-2mm1 of clearance exists between the EGA stop washer and the EGA body. See Figure 6.

GOVERNOR CIRCUIT

BOARD

1_ 5 4 3 2 1 _|

166

169

168 RELAY

I O-

LirJ

GOVERNOR

-0-n

-15

+12 VDC

1-169-TO GOVERNOR ACTUATOR

-79 — FROM RPM SENSOR

Governor Actuator Relay

DESCRIPTION;

See Figure 5. The Relay is housed in the generator

control console. The Relay coil is energized when 12 volts

DC is applied at its Terminal A and the circuit is completed

through the coil to Terminal B and to ground.

TESTING:

To test the Relay, apply +12 volts DC to Relay Terminal

A and -12 volts DC to Terminal B. The Relay coil should

Electronic Governor Setup

The Electronic Governor Control (EGC) circuit board is housed in the generator control console (see Figure 7). All circuit board adjustments for new generators have been completed at the factory and no additional adjustment should be required. If the circuit board must be replaced, adjust the governing parameters as follows:

1. See Figure 7. Set the speed pot (R5) fully counterclock-

wise.

2. Set all other potentiometers (R12, R13, R22, R26) to their mid-point.

Page 7.2-1

Electronic Governor Setup (Continued)

Figure 7. Electronic Governor Control Circuit Board

Set Jumper J2 to Its "FAST* position.

4. Adjust Speed Pot R5 clockwise to obtain the correct AC frequency.

5. Check no-load stability. System stability can be improved by adjusting R12 and R13 clockwise.

6. Apply 25 percent of the unifs rated load. Then, check stability.

a. If undesireable oscillations are observed when the 25%

load is applied, adjust R22 clockwise. b. Adjusting R22 clockwise will dampen undesireable os

cillations that occur when a load Is applied.

7. Shut the engine down. Then, restart it and observe startup characteristics. If the overshoot that occurs during startup is

higher than desired, adjust R26 clockwise (to reduce startup overshoot).

8. Apply rated block load to the generator. Observe the recovery from block load application and from load dump.

a. Adjusting R12 and R13 counterclockwise will improve recovery from block load application, but will tend to make the system less stable.

b. Adjusting R26 counterclockwise will improve recovery from load dump, but will allow more overshoot at startup.

Complete the preceding adjustments as required to ob tain the best balance of all parameters. Basic guidelines for system operation are as follows:

D The system should reach stability at all load points with

not more than four (4) oscillations.

D The system should recover to within one (1) Hertz of

steady state in less than two (2) seconds for all load transients.

CH No-load to full-load droop should be less than 0.5 Hertz

steady state.

The Magnetic Pickup is installed into a threaded hole in

Magnetic Pickup

the generator's blower housing and prevented from turning by a stop nut. The tip of the pickup lies directly over the flywheel’s ring gear teeth.

To install and properly set air gap, thread the pickup in

until its tip just contacts the ring gear. Then, back off about

1/2 to 3/4 turn and hold in that position while tightening the

stop nut.

CAUTION: DO NOT rotate the engine during the above adjustment.

Page 7.2-2

________________________________

Part 8

ENGINE

IGNITION

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

8.1

8.2

TITLE

General Information

Tests, Checks and Adjustments

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Modeis

_________

Section 8.1- GENERAL INFORMATION

_________

The engine ignition system consists of (af ignition coil,

(b) a distributor, (c) spark piugs, (d) spark plug leads, and (e) Firing Order......................................1-3-4-2

an ignition resistor. Distributor Rotation

Breaker Point Gap Distributor Cap insulation

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

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

Counterclockwise

0.018-0.022 inch

Ignition System Operation Resistance................................Greater than 50 meg-ohms

During engine cranking and running op^erations, an En- Head Insulation

gine Control circuit board delivers 12 volts DC to the Ignition cn

Major Components Service Data and Specifications

Coil primary winding via Wire No. 9. the coil primary winding Resistance circuit is completed through the distributor breaker points and Distributor Cap Carbon to ground. Each time the distributor breaker points open, the Point Length

primary circuit is opened and a magnetic lield around the (3mm) protruded length

primary coil winding collapses to induce a high voltage into ignition Coil Resistance

the ignition coil secondary winding. The high voltage from the Primary Coll 1 3-1 5 ohms coil secondary winding jumps the gap across the spark plugs. _ ^ ^

When the engine has started, only about 7-9 v^is . Coll

required to maintain ignition. For that reason, once startup sparK Plugs bodcco

has occured, the Engine Control board terminates current NGK...................................BPR6ES

flow to Wire No. 9 and delivers current flow to the ignition coil CHAMPION

primary winding through a resistor wire (RW). AC .....................................R42XLS

Figure 1. Ignition System Diagram

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

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

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

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

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

Spark Plug Gap Condenser Capacity .. .0.2-0.24 micro-farads

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

Greater than 50 meg-ohms More than 0.012 inch

8.7-11.7 k-ohms

RN9YC

0.031-0.035 Inch

Page 8.1-1

Page 8.1-2

Section 8.2- TESTS, CHECKS AND ADJUSTMENTS

See Figure 3. Connect the test leads of an ohmmeter

Ignition Coil

across the positive and negative terminals of the primary v/inding. Measure the resistance.

PRIMARY WINDING RESISTANCE

AT 68* F. (20‘ C.)

1.3-1.5 ohms

Connect the ohmmeter test leads across the secondary

winding terminal and the primary winding negative terminal.

Measure the resistance.

SECONDARY WINDING RESISTANCE

AT 68* F. (20* C.)

8700-11,700 ohms

Figure 4. Checking Secondary Winding Resistance

Distributor Cap and Rotor Head

Inspect the cap and rotor head for dust, carbon deposits,

cracks. Replace, if necessary.

Contact Set

Inspect surfaces of the contact points. Irregularities may be rernoved with No. 500 or 600 sandpaper or with oilstone. Loosen the breaker point set screw and adjust gap with a feeler gauge.

BREAKER POINT GAP

0.018-0.022 Inch (0.45-0.55mm)

Check Governor Advance

Turn the rotor shaft counterclockwise, then release it and check that it returns to the clockwise position. Also check that the rotor shaft is not excessively loose.

Use a capacity tester to check the condenser. If a capac

Checking the Condenser

ity tester is not available, avolt-ohm-milliammeter(VOM) may be used to test the condenser, as follows:

1. S^t the VOM to a high resistance scale, such as *Rx1 K" or ”Rx10,000". Zero the meter.

2. Connect VOM test leads across the condenser. If the VOM needle swings violently, then moves back to “Infinity" grad ually, condenser is good. A reading of “zero” or a steady reading indicates the condenser has failed.

2. Use a spark plug wrench to remove spark plugs.

3. Clean the spark plugs in a sand blast cleaner. Inspect insulators for cracks, chipping. Inspect gasket. Check elec trode for wear, burning or pitting. Replace plug(s) if defective.

4. Check spark plug gap (Figure 7).

SPARK PLUG GAP

0.031-0.035 inch

5. Install and tighten to 14-22 foot-pounds. Install wires.

Page 8.2-1

Spark Plugs (Continued)

Use an automotive timing iight to check and adjust

Ignition Timing

ignition timing. A timing mark is provided on the crankshaft pulley and a degree indicator is also provided. Set timing with the engine running at no-load as follows:

IGNITION TIMING AT 1860 RPM

21‘BTDC

Figure 9. Ignition Timing

Carefully inspect high tension leads for damage, cracks,

Checking Ignition Wires

burned terminals, proper fit. Measure the resistance of each wire (Figure 8). Shake the wires during the test.

IGNITION WIRE RESISTANCE

Less than 30,000 ohms

Page 8.2-2

Part 9

SECTION

9.1

9.2

TITLE

Standard Battery Charging System

The "DELCO®" Charging System

ENGINE

ELECTRICAL

SYSTEM

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Modeis

9.3

9.4

9.5

Engine Cranking System

Engine Controi Circuit

Troubleshooting Guide

Section 9.1- STANDARD BATTERY CHARGING SYSTEM

A DC ALTERNATOR supplies charging current to the

Components

unit battery during engine operation, as regulated by a DC VOLTAGE REGULATOR. The circuit is protected by a 30 amp FUSE.

DC Alternator

The belt driven, permanent DC alternator is part of the engine governor. Maintenance on the DC alternator is limited to replacement of defective parts. See Part 7, Section 7.1,

"MECHANICAL GOVERNOFT.

Figure 1. Battery Charging System

The solid state DC voltage regulator is housed in an

DC Voltage Regulator

aluminum heat sink. All components are buriedjn an epoxy

resin and the DC regulator is not repairable.

Pin 1= charging output to battery (12.5-14.5 volts DC)

Pin 2= charging Input from DC alternator. Pin 3= charging Inplut from DC alternator. Pin 4= Not used (charging Indicator lamp)

Pin 5= sensing voltage from battery.

DC regulator

Page 9.1-1

Section 9.2- THE "DELCO®" CHARGING SYSTEM

Some industrial-mobile (IM) engine-generators may be

Introduction

equipped with a ’Delcotron®“ battery charging system. This system utilizes a belt driven DC alternator having an integral

DC voltage regulator.

See Figure 2. During cranking and running operations, an engine control circuit board delivers battery voltage to the DC alternator via Wire No. 14, a resistor (R1) and a diode (D1). This is DC alternator field excitation current. DC alter nator output (charging) current is delivered to the battery via

Wire No. 13.

DC Alternator Description

See Figure 3. The DC alternator consists primarily of 2 end assemblies, rotor, stator, brushes, slip rings and diodes. The rotor is supported in the drive end frame by ball bearings and in the slip ring end frame by roller bearings. Bearings contain sufficient lubricant to eliminate the need for periodic lubrication.

DC Alternator Adjustments

No periodic adjustment or maintenance is required on the DC alternator assembly. Regulator voltage is preset and

no regulator adjustment is needed.

CAUTION: Do NOT attempt to polarize the DC alternator. Do NOT short or ground any terminals except as Instructed. Never operate the DC alter nator with battery out of circuit or with output terminal open. The DC alternator and the battery must share the same ground polarity.________________

Testing

GENERAL:

Beforte starting electrical checks, visually inspect all terminals for clean and tight connections. Check DC alterna tor mounting bolts and dnve belt tension. Do NOT ground the No. 2 lead wire. Battery must be in good condition to test the charging system.

Delcotron Series

System Voltage..................................................12

DELCO® Regulator No......................................1116392

Ground Polarity...................................................Negative

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

Figure 3. "Delcotron" DC Alternator

Slip Ring

End Frame

10 SI

Bearing

UNDERCHARGED BATTERY:

1. Connect a DC voltmeter from the DC alternator “BAT" terminal to ground (Figure 4). Crank the engine and nore the meter reading. A “zero" reading indicates an open condition between the “BAT“ connection and the engine control circuit board.

a. If reading is “zero“ on gaseous fuel unit, test Wire 49 between DC alternator and diode (D1) for open. Check diode (D1) and resistor (R1), as weil as Wire 14 for open.

b. If unit is a gasoline fueled unit and reading is "zero", check Wire 49, diode (D1), resistor (R1) and Wire 14

between DC alternator and carburetor fuel valve for open. Also check Wire 14, between carburetor fuel valve and engine control circuit board, for open.

Rotor

Stator

2, Disconnect the battery ground cable. Connect an ammeter

Testing (Continued)

jin series at “BAT" terminal of DC alternator. See Figure 5. ' Reconnect the battery ground cable. Connect a carbon pile

across the battery. Operate engine at 1860 rpm and adjust carbon pile as necessary to obtain maximum current output.

a. If ampere output Is within 10 amps of the rated output stamped on DC alternator case, the alternator is good.

b. If output is NOT within 10 amps of rated output, ground the field windino tab by inserting a screwdriver into the end case test hole (Figure 6).

CAUTION; The field winding tab is within 3/4 inch of the casting surface. Do NOT force screwdriver deeper than 1 Inch Into end frame._____________________

c. With field winding tab grounded, run engine at 1860 rpm and again adjust carbon pile to obtain maximum current output. If output is now within 10 amps of rated output, check the field winding and check DC voltage regulator with tester. If output is NOT within 10 amps of rated output, check field winding, diode trio, rectifier bridge and stator.

OVERCHARGED BATTERY;

Connect a voltmeter from the DC alternator's No. 2

terminal to ground. If reading is “zero“. No. 2 lead circuit is

open. If the battery and the No. 2 lead circuit test good, but overcharge exists, overhaul the DC alternator. Check field

windings for grounds and shorts. If defective, replace rotor

and test regulator.

Figure 6. Grounding the Field Winding Tab

Insert Screwdriver And Ground Tab

To End Frame By.Touching Screwdriver

To Both Tab and End Frame

End Frame

Hole

Page 9.2-2

Section 9.3- ENGINE CRANKING SYSTEM

Cranking System Description

See Figure 7, below. Battery power is available to a large terminal stud of the STARTER CONTACTOR. How ever, the STARTER CONTACTOR contacts are normally-

open. From the STARTER CONTACTOR, battery voltage is

available to the ENGINE CONTROL circuit board, via Wire 13, a 10 amp CIRCUIT BREAKER, and Wire 15. Major

components of the engine cranking system include the fol

lowing:

D Engine control circuit board.

D Start-Stop switch,

n 10 amp Circuit Breaker.

Starter Contactor,

n Starter.

12 volts Battery.

Figure 7. Engine Cranking System Diagram

Engine Control Circuit Board

See Section 9.4, "ENGINE CONTROL CIRCUIT.

Start-Stop Switch

DESCRIPTION;

See Figure 8. Wires 17 (start), 18 (stop), and 0 (ground)

connect to the start-stop switch terminals.

Setting the switch to "Start" connects the Wire 17 circuit

to Wire 0 (ground). Engine control circuit board action then

initiates engine cranking and startup.

Setting the switch to "Stop" connects the Wire 18 circuit

to ground. The circuit board.then opens its circuit to Wire 14

and engine shutdown occurs.

Operation of the engine cranking system may be briefly

Operational Analysis

descrioed as follows (Figure 7):

1. Battery power is available to the STARTER CONTACTOR,

via the positive battery cable. Battery power is also available to the ENGINE CONTROL circuit board, via Wire 13, a 10 amp CIRCUIT BREAKER, and Wire 15.

2. When the START-STOP SWITCH is set to “Start", Wire 17 and Pin 3 of the ENGINE CONTROL board are connected to ground. Circuit board action then delivers 12 volts DC to the STARTER CONTACTOR coil, via Wire 56. The STARTER CONTACTOR is energized and its contacts close.

3. On closure of the STARTER CONTACTOR contacts, 12

volts DC is delivered to the STARTER. The engine cranks.

4. When the engine starts, the START-STOP SWITCH is released and Wire 17 is no longer grounded. Circuit board

action opens the 12 volts DC circuit to Wire 56 and cranking terminates.

TESTING THE SWITCH:

The start-stop switch can be tested using a volt-ohm-milliammeter (VOM). Set the VOM to its "Rxl" scale and zero the meter.

D Connect the VOM test leads across the Wire 17 and the

Wire 0 terminal of the switch. With switch at “Start", the

meter should read "continuity": at “Stop", switch should

read “infinity".

D Connect the VOM test leads across the Wire 18 and the

Wire 0 terminals of the switch. Set switch to “Start" and

meter should read “infinity". Set switch to “Stop" and it

should read “continuity”.

10 Amp Circuit Breaker

Refer to Section 9.4, "ENGINE CONTROL CIRCUIT.

Starter Contactor

DESCRIPTION:

The starter contactor (or starter solenoid) is attached to the engine-generator control panel. See Figure 9.

TESTING THE STARTER CONTACTOR:

If the engine will not crank, the starter contactor can be

tested as follows:

1. Check for normal battery voltage at the large terminal stud to which the positive battery cable connects.

a. If battery voltage is zero or low, check the battery cable and the battery.

b. If normal battery voltage is read, go on to Step 2.

Page 9.3-1

2. Connect the positive VOM test iead to the large contactor

starter Contactor (Continued)

terminal stud to which the starter cabie attaches and the common VOM test iead to ground. Hold the start-stop switch

at “Start“ and battery voltage should be indicated,

a. If normal battery voltage is indicated, but engine does

not crank, check the contactor to starter cable and the

starter itself. b. If normal battery voltage is NOT indicated when the

start-stop switch is set to “Start“, go to Step 3.

3. Check for battery voltage at the small starter contactor terminal to which Wire 56 attaches. When the start-stop switch Is set to “Start" battery voltage should be indicated,

a. If batte^ voltage is indicated in Step 3 but was NOT

indicated in Step 2, check the starter contactor ground

wire. If ground wire is good, replace the starter contactor,

b. If battery voltage is NOT indicated in Step 3 when the

start-stop switch is set to "Start“, check the following:

(1) Wire 56 between the starter contactor and the engine

control circuit board.

(2) The start-stop switch. (3) The 10 amp circuit breaker. (4) Power supply to the engine control circuit board.

springs. Tighten brush screw to 30-35 inch-pounds. Tighten the hot stud nut to 45-50 inch-pounds.

5. Armature: Check the armature for an open, shorted or grounded condition with a growler. Hold armature in a vise while installing or removing the drive assembly. Apply a thin film of non-conducting grease to the commutator end of the armature shaft and to the portions of the shaft that contact the bearings.

STARTER PERFORMANCE TEST:

CAUTION: DO NOT operate the starter continuously for longer than 30 seconds.

_____________________

Use a fully charged, 12 volts battery to test the starter. Attach the battery’s positive terminal to the starter motor input stud, and the battery negative terminal to the starter motor housing. Use a No. 10 (or larger) cable not more than 6 feet long. Maximum current draw and starter speed should be as follows:

MAXIMUM NO-LOAD CURRENT DRAW & SPEED

17 amps at 6000-7200 rpm

Battery

RECOMMENDED BATTERY:

When anticipated ambient temperature will consistently be above 32" F. (O’ C.), use a 12 volts, automotive type storage battery rated at 70 amp-hours and capable of deliv ering at least 360 cold cranking amperes.

If ambient temperatures will be below 32" F. (O’ C.), use a 12 volts battery rated 95 amp-hours and having a cold cranking capacity of 450 amps.

Starter

DESCRIPTION:

The starter assembly is shown in Figure 10. It is rated 12 volts DC. Never apply any voltage in excess of rated voltage or magnets in the starter may become demagnetized.

STARTER MOTOR SERVICING:

1. Inspection: Check for adverse wear on all bearings, gears, shafts, etc. Check the sprino washer for wear, convex side next to bearing. Add a drop of oil to face of bearing.

2. Thru-Bolts: Tighten thru-bolts to 75 inch-pounds.

3. Drive Cap: Apply a film of SAE #10 oil to the bearings in the drive cap. During reassembly, the insulating washer must be placed against the drive cap.

4. Brush Assembly: Brushes and brush springs should be replaced at each overhaul. Any brush that is worn to 5/16 inch or less, measured on short side of brush, or that has been in contact with grease, oil or cleaning fluid, must be replaced. Assemble brushes with their chamfered side sway from the

BA’TTERY CABLES:

Use of battery cables that are too small in diameter or too long will result in excessive voltage drop. For best cold weather starting, voltage drop between the battery and starter should not exceed 0.12 volt per 100 amperes of cranking current.

Select battery cables based on total cable length and prevailing ambient temperatures. Generally, the longer the cable and the colder the weather, the larger the required cable diameter. The following chart applies:

CABLE LENGTH (IN FEET)

TTTB 16-20 No. 000

EFFECTS OF TEMPERATURE ON BATTERY:

RECOMMENDED CABLE SIZE

R5r2

RoTO

Battery efficiency is greatly reduced by a decreased electrolyte temperature, because such low temperatures have a decided numbing effect on the electrochemical action. Under high discharge rates (such as cranking), battery volt age will drop to much lower values in cold temperatures than in warm temperatures. The freezing point of battery electro lyte fluid is affected by the state of charge of the electrolyte.

SPECIFIC GRAVITY

1.220

1.200

TTreo

FREEZING POINT

^3rT;"(-37' c. )

-SO' F. (-29' C.) ITTVi-IO' C.)

Page 9.3-2

---------

Figure 10. Starter Assembly

DRIVE KIT

“B

DRIVE PINION

COMMUTATOR

CAP

O O Ù ^

BRUSH & SPRING KIT

PARTS IN COMMUTATOR CAP

DRIVE CAP

THRU BOLTS

ARMATURE

ASSEMBLY

Page 9.3-3

Battery (Continued)

ADDING WATER:

Water is lost from the battery as a result of charging and

^discharging, and must be replaced. If the water is not re

placed and the separator plates become exposed, they may become permanently sulfated. In addition, the plates cannot

take full part in the battery action unless they are completely

immersed in electrolyte.

CHARGING A BATTERY:

When charging a battery, an explosive gas mixture forms in each cell. Battery electrolyte fluid is an extremely caustic sulfuric acid solution that can cause severe burns. For that reason, the following precautions must be observed;

□

The area must be well ventilated.

Do NOT smoke or break a live circuit near the top of the

□

battery- sparking could cause an explosion.

□

Avoid spillage of battery electrolyte fluid. If spillage oc curs, flush the affected area with clear water im mediately.

Wear eye protection when handling a battery.

□

Page 9.3-4

Section 9.4- ENGINE CONTROL CIRCUIT

An engine control circuit board (Figure 11), noused in the

Engine Control Circuit Board

generator control panel, controls engine starting, running and shutdown functions. A 12 volts DC power supply is delivered to the board for control of those functions.

Circuit board terminals, connecting wires and a descrip

tion (or function) of the wires is listed in the following chart:

Figure 12. Engine DC Control Circuit

TERMINAL

1 15

2 3

4 18

5&6

7 56

12 85

WIRE

11, 22 Frequency (engine speed) signals

DESCRIPTION OR FUNCTION

Breaker protected 12 volts DC power

to operate engine control system.

14 Delivers 12 volts DC to carburetor

Common ground.

Engine will crank when this circuit

Engine will shut down when this

from generator AC power leads for

fuel valve, fuel pump and DC alter

Once cranking has ended, battery

power Is delivered to the Ignition

When this circuit Is grounded by

automatic engine shutdown will

is grounded.

circuit is grounded.

automatic engine shutdown.

Crank signal- starter contactor

energizes when circuit board

energizes Wire 56 circuit.

Delivers 12 volts DC to ignition

coil for engine cranking only.

nator for running.

coil via a resistance wire.

Delivers 12 volts DC to a

remote panel only when the

engine is running.

closure of either (a) a low oil

pressure switch, or (b) a high

coolant temperature switch, an

occur

Page 9.4-1

Enqine Control Circuit Board (Continued)

See Figure 11 on previous page. The service technician hould be aware of the following features on the engine ontrol circuit board:

1. An adjustment potentiometer (R19) is provided to permit adjustment of the rpm at which an overspeed shut down will occur.

a. Automatic shutdown should occur when AC frequency

(engine speed) exceeds approximately 69-71 Hertz (2070-

2130 rpm).

b. Adjustment is required whenever the engine control

circuit board is replaced.

2. The circuit board mounts a red crank lamp (LED) which should turn on when the engine is cranking.

a. A “Lamp On" condition indicates that (a) the Wire 17 circuit has been grounded by start-stop switch action, and (b) circuit board action has delivered battery voltage to the Wire No. 56 circuit to initiate cranking.

b. The lamp should go out when the start-stop switch is released and cranking has terminated.

3. The circuit board mounts a green run iamp (LED).

a. The run lamp should illuminate when circuit board action has delivered 12 volts DC to the Wire No. 14 circuit (to open the carburetor fuel valve, and turn on the fuel pump).

b. If the run lamp does NOT turn on during cranking, engine will not start.

Overspeed Shutdown Adjustment

To adjust the overspeed shutdown setting, proceed as

follows:

1. On the engine control circuit board, turn the OVERSPEED SHUTDOWN POT counterclockwise until it just contacts its stop. DO NOT FORCE.

2. Connect an accurate AC frequency meter across the generator’s AC output leads.

3. Start the engine, let it stabilize and warm up at no-load.

4. SLOWLY increase engine speed until the frequency meter reads 69-71 Hertz.

5. Hold the throttle at 69-71 Hertz, then SLOWLY turn the OVERSPEED SHUTDOWN POT clockwise. When the en gine shuts down, overspeed setting is correct.

Page 9.4-2

TEST 1- CHECK

10 AMP CIRCUIT BREAKER POSITION

Section 9.5- TROUBLESHOOTING GUIDE

Problem 1. Engine Will Not Crank

CLOSEDhhh^

TEST 2-CHECK

VOLTAGE AT

STARTER

CONTACTOR

TERMINAL

— GOOD ^

TEST 3-CHECK

VOLTAGE AT

STARTER

CONTACTOR

o 1 1

CABLE

1 bHMiNAL

I BAD.

OPEN

CLOSE CIRCUIT BREAKER

TEST 4-CHECK

BATTERY

CABLES

CLEAN OR REPLACE

TEST 8- CHECK VOLTS O.K. WIRE 56 VOLTS

AT STARTER CONTACTOR

IGOOD.

mmm NOW BUTi^h^-

NOT IN CONTACTOR

TEST3

BAD

TEST 5-CHECK

BATTERY

BAD

RECHARGE OR REPLACE

TEST 9-CHECK

STARTER ^HGOOCtai^

GROUND

BAD

CLEAN OR REPLACE

GOOD BUT WONT CRANK

■ W

REPLACE STARTER

CONTACTOR

TEST 7- CHECK

STARTER

MOTOR

BAD

REPAIR OR REPLACE

NO GOOD

TEST 10-CHECK

WIRE 56

BAD

REPAIR, RECONNECT

OR REPLACE

GOOD.

BAD

REPAIR OR REPLACE

TEST 11-TEST

10 AMP

BREAKER

BAD

iGOO

REPLACE

BAD

REPLACE

TEST 12-TEST START-STOP

SWITCH

-T

iGOOC^

TEST 13-CHECK POWER SUPPLY

TO CIRCUIT BOARD, IF GOOD

REPLACE ENGINE CONTROL

CIRCUIT BOARD

Page 9.5-1

Problem 2. Engine Cranks But Will Not Start

TEST 14-CHECK

FUEL SUPPLY

•l

OUT OF FUEL

REPLENISH FUEL SUPPLY OR TURN

ON FUEL AS

REQUIRED

TEST 17-CHECK

FUEL PUMP

BAD

iO.Kj

GOOD^B^

TEST 15-CHECK

ENGINE CONTROL

CIRCUIT BOARD

WIRE #14

OUTPUT

NO WIRE #14 OUTPUT

REPLACE ENGINE

CONTROL

CIRCUIT BOARD

TEST 18-TEST

AUTOMATIC CHOKE

(GASOLINE ONLY)

BAD

iO.Kj

_GOOD^^

TEST 16-CHECK

FUEL VALVE

BAD

REPLACE FUEL

VALVE

TEST 19-CHECK

ENGINE

IGNITION

SYSTEM

bId

1 GOODi

GOODk

REPLACE BAD PUMP

TEST 20-CHECK

ENGINE FUEL SYSTEM

iGOOC

REPLACE BAD PART(S)

TEST 21-CHECK

ENGINE

MECHANICAL

SYSTEMS

REPAIR OR REPLACE

PART(S) AS

NECESSARY

Page 9.5-2

Test numbers in the test procedures that follow corre

Introduction

spond to the numbered tests in the troubleshooting flow

charts of Pages 9.5-1 and 9.5-2.

Test 1- Check 10 Amp Circuit Breaker

Position

DISCUSSION:

Battery power must be available to the engine control circuit board in order for engine cranking to occur. This power is delivered to the circuit board via Wire 13, the 10 amp circuit breaker and Wire 15. If the 10 amp breaker is open, cranking will not be possible.

PROCEDURE:

Check if 10 amp breaker is set to “Off“ or "Open”. If it is

set to “Off" or "Open", reset it to its “On“ or "Closed" position.

Test 5- Check Battery

DISCUSSION:

If the engine will not crank, the unit battery may be

discharged or worn out. ',

PROCEDURE:

Use an automotive type battery hydrometer to test the battery for (a) state of charge and (b) condition. Follow the hydrometer manufacturer’s instructions carefully.

State of Charge: If the hydrometer used does not have a “Percentage of Charge" scale, the following chart may be used:

SPECIFIC GRAVITY PERCENTAGE OF CHARGE

1.260

1.230

T25S

1.170

ÏÔÜ95

7s^

5ÜÎ5

25^S

RESULTS:

1. If the 10 amp breaker is set to “On" or "Closed", go on to

Test 2.

2. If the 10 amp breaker is set to "Off" or "Open", reset it to its "On" or "Closed" position.

Test 2- Check Voltage at Starter Contac

tor Battery Terminal

DISCUSSION:

See “reST/NG THE STARTER CONTACTOR' on

Pages 9.3-1 and 9.3-2.

RESULTS:

1. if battery voltage is read at the starter contactor battery

terminal, go on to Test 3.

2. If low or no voltage is indicated at starter contactor battery terminal, go on to Test 4.

Test 3- Check Voltage at Starter Cable

Terminal

DISCUSSION:

See "TESTING THE STARTER CONTACTOR" on Pages

9.3-1 and 9.3-2.

RESULTS:

1. If low or no voltage is indicated at starter cable terminal

stud of starter contactor when start-stop switch is held at

"Start", go to Test 8.

2. If normal battery voltage is indicated at starter cable terminal stud of the starter contactor when start-stop switch

Is set to “Start", but the engine will NOT crank, go to Test 6.

Test 4- Check Battery Cables

DISCUSSION:

See "TESTING'THE STARTER CONTACTOR" on Pages

9.3-1 and 9.3-2.

RESULTS:

Clean or replace battery cables as necessary. If battery cables are good, go to Test 5.

Condition: If the difference in specific gravity between

the highest and lowest reading cells is greater than 0.050 (50

points), the battery should be replaced.

RESULTS:

1. Recharge or replace battery as needed.

Test 6- Check Starter Cable

DISCUSSION:

When the start-stop switch is set to "Start", battery volt age should be available at the starter motor, indicating that the starter contactor has energized and its contacts have closed. If such voltMe was available at the starter contactor

(Test 3) but is NOT available to the starter motor terminal stud, the starter cable (bètween the contactor and the starter) is corroded or defective.

PROCEDURE:

Check for battery voltage at the starter motor terminal

stud when the start-stop switch Is set to "Starf.

RESULTS:

1. Clean or replace starter contactor to starter motor

cable as required.

2. If starter cable is good, go to Test 7.

Test 7- Check Starter Motor

DISCUSSION:

Refer to Section 9.3.

Test 8- Check Wire 56 Volts at Starter

Contactor

DISCUSSION:

When the start-stop switch is set to "Start", engine control circuit board action should deliver battery voltage to the Wire 56 terminal of the starter contactor. The starter contactor should then become energized and the engine should crank.

This test will determine if battery voltage Is available to

energize the starter contactor and initiate cranking.

Page 9.5-3

Test 8- Check Wire 56 Volts at Starter

Contactor (Continued)

ROCEDURE:

See "STARTER CONTACTOR" on Pages 9.3-1 and

9.3-2.

RESULTS:

1. If battery voltage is not Indicated, go to Test 10.

2. If normal battery voltage is Indicated In this test, but was NOT indicated in Test 3, go to Test 9.

Test 9- Check Starter Contactor Ground

DISCUSSION:

A ground wire connects to one of the smaller starter contactor terminals and to frame ground. If this wire is open or if a good ground connection is not available, the starter contactor will not energize.

PROCEDURE”

Test the starter contactor ground lead for "continuity".

DISCUSSION:

Test 12- Test Start-Stop Switch

When the start-stop switch is set to "Start", switch action must connect Wire 17 to ground or cranking will not occur, in addition, when the switch is set to "Stop", Wire 18 must be

connected to ground or engine shutdown will not occur.

PROCEDURE:

1. Connect VOM test leads across the Wire 17 terminal of switch and the Wire 0 (ground) terminal. Set Switch to "Start" and meter should read^continuity". Set switch to "Stop" and meter should read "infinity".

2. Connect the VOM test leads across Wire 18 terminal of switch and Wire 0 terminal. Set switch to "Start" and VOM should read "infinity". Set switch to "Stop" and meter should read "continuity".

RESULTS:

1. Replace the start-stop switch if it fails the test.

2. if switch is good, go to Test 13.

RESULTS:

1. Repair, reconnect or replace the starter contactor ground

wire as necessary.

2. if the ground lead is good, replace the starter contactor.

Test 10. Check Wire 56

ISCUSSION:

if Wire 56, between the engine control circuit board and the starter contactor, is open, cranking will not occur when the start-stop switch is set to "Start".

PROCEDURE:

Inspect Wire 56 between the starter contactor and the engine control circuit board. Test the wire for "continuity".

RESULTS:

1. Repair, reconnect or replace Wire 56 as required.

2. if Wire 56 is good, go to Test 11.

Test 11. Test 10 Amp Circuit Breaker

DISCUSSION:

Battery power must be available to the engine control circuit board or cranking cannot occur, if the 10 amp breaker has failed open, battery power will not be available to the circuit board.

PROCEDURE:

Test the 10 amp breaker for continuity with the breaker

set to "On" or "Closed".

RESULTS:

1. Replace the 10 amp breaker, if it is defective, if the 10 amp breaker is good, go to Test 12.

Test 13. Check Power Supply to Circuit

Board

DISCUSSION:

In test 8, battery voltage was NOT available to the Wire 56 terminal of the starter contactor. Wire 56 was checked in Test 10 and it was good. The 10 amp breaker was then tested, as well as the start-stop switch, and both were good. The engine control circuit board is left as a suspect.

PROCEDURE:

Connect a DC voltmeter across circuit board Pin #1 and ground. Battery voltage should be indicated.

RESULTS:

if battery voltage is indicated, replace the engine control circuit board.

NOTE: Perform Tests 14 through 21 If the enhgine cranks normally, but will not start.

Test 14. Check Fuel Supply

DISCUSSION:

Orten, the most obvious cause(s) of a problem are overlooked when troubleshooting.

PROCEDURE:

if the engine cranks but will not start, check the fuel supply. Also make sure that any shutoff valve(s) in the fuel supply lines are open.

RESULTS:

1. Replenish fuel supply as necessary.

2. if fuel supply is good but engine will not start, go to Test

15.

Page 9.5-4

Test 15. Check Engine Control Circuit

Board Wire #14 Output

DISCUSSiON:

During a startup attempt, when the start-stop switch is set to “Start“, engine control circuit board action must deliver battery voitage to the Wire 14 circuit. Wire 14 voitage ener gizes a fuel solenoid open to aliow fuel flow. On units with gasoline fuel system, Wire 14 turns on the fuel pump. And, on units with electronic governor. Wire 14 turns on the gov ernor circuit.

The fact that the engine cranks when the start-stop switch is set to "Start“ is adequate verification that battery power is available to the engine control circuit board.

PROCEDURE:

Use a VOM to check for batteiy voltage at terminal #9 (Wire 14) of the engine control circuit board when the engine is being cranked. Battery voltage should be indicated.

RESULTS:

1. If battery voltage is indicated, go to Test 16.

2. If battery voltage is NOT indicated, replace the engine control circuit board.

Test 16. Check Fuel Valve

DISCUSSION:

Units with gasoline fuel system are equipped with a fuel solenoid valve that is attached to the gasoline carburetor (see Part 5 of this Manual).

Units with gaseous fuel system have separately mounted solenoid valve (see Part 6).

The fuel valve MUST open if fuel Is to be introduced to the engine carburetor.

Test 17. Check Fuel Pump

DISCUSSION:

This check applies to gasoline fuel systems only, since gaseous fuel systems do not require a fuel pump. The fuel pump MUST operate on these systems or the engine will not start.

PROCEDURE:

See Section 5.2 of this Manual.

RESULTS:

1. Replace fuel pump if defective.

2. If fuel pump is good, go to Test 18.

Test 18. Test Automatic Choke

DISCUSSION:

This test applies to gasoline fuel systems only, since

gaseous fuel systems do not require a carburetor choke. The automatic choke on gasoline units actuates only during en gine cranking.. Choke operation is terminated at the same

time that cranking ends.

PROCEDURE:

1. Crank the engine. During cranking, the choke solenoid

should pull in about every 2 to 5 seconds.

a. If choke solenoid functions normally, go to Test 19. b. If choke solenoid does NOT pull in while cranking, go to

Step 2.

2. Try adjusting the choke. See "AUTOMATIC CHOKE AD JUSTMENT" on Page 5.3-1.

3. Inspect ground wire (No. 0) between choke module and start-stop switch.

4. Disconnect Wire 90 from choke module and hold it into firm contact with a clean frame ground. When engine is cranked, choke solenoid should pull in.

PROCEDURE:

Gasoline Units: Remove the fuel valve from the engine carburetor. Hold the valve housing into firm contact with a clean frame ground and set the start-stop switch to "Start". The valve tip should pull in, indicating that it has been actu ated to its open position.

Gaseous Fuel Units: Disconnect the inlet and outlet lines from the gaseous fuel valve. Apply 12 volts DC to the valve wires and the valve should open. Remove the 12 volts

DC and the valve should close. Use your mouth to blow

through the valve, to verify valve open and closed conditions.

CAUTION: If 12 volts DC Is available to the gas eous system fuel valve, but valve does not appear

to open, be sure to check gaseous fuel pressure

before rejecting the valve. At pressures in excess of 14 inches water column (1/2 psi), the valve may not open.

RESULTS:

1. Replace fuel valve if it is defective.

2. If fuel valve checks good, go to Test 17.

________________________________________

RESULTS:

1. Repair, replace or reconnect ground wire (Step 3) as necessary.

2. In Step 4, if choke solenoid pulls in when engine is cranked and Wire 90 is grounded but does NOT puil in otherwise, replace the choke module.

3. In Step 4, if choke solenoid does not pull in and does not actuate normally either, replace the choke solenoid.

Test 19. Check Engine Ignition System

DISCUSSION:

If engine cranks normally but won't start, the ignition system may be at fault.

PROCEDURE:

Test ignition system. See Part 8 of this Manual.

RESULTS:

1. Repair or replace defective ignition system parts as re quired.

2. If ignition system is functioning normally, go to Test 20.

Page 9.5-5

Test 20. Check Engine Fuel System

DISCUSSION:

It the engine cranks normally but will not start, the fuel

Fsystem may be the cause of the problem. Refer to Part 5 for

information on gasoline fuel systems; or Part 6 for gaseous

fuel systems.

RESULTS:

1. Repair or replace defective fuel systems components.

2. If fuel system is functioning properly, go to Test 21.

Test 21- Check Engine Mechanical Sys

tems

DISCUSSION:

failure of the engine to start may be the result of a

mechanical problem in the engine.

PROCEDURE:

See PartT,""ENGINE MECHANICAL". Check engine

compression (see Page 2.1-1).

Page 9.5-6

Part 10

OPTIONS

AND

ACCESSORIES

NP and IM Series

RECREATIONAL

VEHICLE &

INDUSTRIAL

SECTION

10.1

10.2

TABLE OF CONTENTS

TITLE

Remote Start-Stop Panels

Remote Gauge Panel

MOBILE

AC GENERATORS

1.2 Liter, Liquid-Cooled

Gas/Gasoline Engine Models

Generac 86640 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

SERVICE

Manual

Foreword

PURPOSE OF MANUAL:

USER’S RESPONSIBILITY:

SAFETY:

FASTENERS:

REPLACEMENT PARTS:

NP and IM Series

TABLE OF CONTENTS

NP and IM Series

Manual Familiarization

Section 1.1- HOW GENERATORS PRODUCE ELECTRICITY

Magnetic Induction

A Simple AC Generator

A More Sophisticated Generator

A Typical AC Generator

Rotor Residual Magnetism

Field Boost

Excitation System

BRUSHES AND SLIP RINGS:

Stator AC Power Connection Systems

stator AC Power Connection Systems (Continued)

3-PHASE DELTA STATOR SYSTEM:

Generator Disassembly

Introduction

Inspection of Major Components

Section 1.3- INSULATION RESISTANCE TESTS

Effects of Moisture and Dirt

Insulation Resistance Testers

Insulation Resistance- Main Stator

Rotor insuiation Resistance

Drying the Generator

Cleaning the Generator

Drying the Generator (Continued)

Section 1.4- INTRODUCTION TO TROUBLESHOOTING

Introduction

Tools and Equipment

Rotor Rotational Speed

Rotor Rotational Speed (Continued)

Relationship of Voltage & Frequency

Visuai inspection

Constant Excitation Test

Measuring Current

Effects of Engine Power

Measuring Resistance

Section 1.5- TROUBLESHOOTING FLOW CHART

Using the Troubleshooting Flow Chart

Introduction

Test 3- Check Load Watts and Amperes

Test 6- Do a Fixed Excitation Test

Test 7- Check Wires 1 and 4

Test 8- Check Rotor

Test 9> Check Brushes and Slip Rings

Test 10- Test Main Circuit Breaker

Test 12- Test DPE Circuit Breaker

Test 13- Test Thermal Protector

Test 14- Test Stator DPE Windings

Test 15- Test Stator AC Power Windings

Test 16- Check Sensing Leads

Test 17- Check Voltage Regulator

Introduction

Tightening Cylinder Head Boits

EXHAUST MANIFOLD NUTS:

CARBURETOR BOLTS:

Adjusting Vaive Clearance

Checking Drive Beits

Measuring Compression Pressure

Timing Belt Precautions

Timing Beit Removai

BELT TEETH ARE WORN:

Timing Belt Installation

Cylinder Head Removal

Checking Cylinder Head Distortion

Valve Guide Replacement

Camshaft Bearing Clearance