SERVICE MANUAL
Models 940-2
SERIES IMPACT 36 PLUS
P. O. Box 297 Whitewater, WI
NOTICE TO USERS OF THIS MANUAL
SAFETY
REPLACEMENT PARTS
TABLE OF CONTENTS
SERVICE MANUAL
TROUBLESHOOTING
SPECIFICATIONS & CHARTS
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PART GENERAL INFORMATION
COMPONENTS TESTING
COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS
Series Impact 36 Plus
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MAGNETISM
Section GENERATOR FUNDAMENTALS
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC INDUCTION
ELECTRICAL UNITS
ALTERNATING CURRENT
Figure 4. Operation of a Simple Generator
Figure 5. Alternating Current Sine Wave
REACTANCE IN AC CIRCUITS
OHMS LAW
Figure 6. Electrical Units
AMPERES = VOLTSOHMS
Figure 9. Capacitive Reactance
Figure 10. Block Diagram of the Impact 36 Plus System
Section GENERATOR FUNDAMENTALS
CAPACITIVE REACTANCE
Section GENERATOR FUNDAMENTALS
WHY VARIABLE SPEED CONTROL?
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Section GENERATOR FUNDAMENTALS
Figure 2 Permanent Magnet Rotor Assembly
UPPER FAN HOUSING
Section MAJOR GENERATOR COMPONENTS
INTRODUCTION
ROTOR HUB
STATOR ASSEMBLY
STATOR RETAINING RING
STEPPER MOTOR
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Figure 5. Schematic- Stator Windings
Section MAJOR GENERATOR COMPONENTS
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Section MAJOR GENERATOR COMPONENTS
Section OPERATIONAL ANALYSIS
Figure 1. Block Diagram- A Generator System
GENERAL
OPERATIONAL DESCRIPTION
Section OPERATIONAL ANALYSIS
OPERATIONAL DESCRIPTION CONTINUED
Section INSULATION RESISTANCE
CAUTION! When using a Megohmmeter or
DIRT AND MOISTURE
INSULATION RESISTANCE TESTERS
TEST ALL STATOR WINDINGS TO GROUND
CLEANING THE GENERATOR
TEST FOR SHORTS BETWEEN WINDINGS
RESULTS OF TESTS
DRYING THE GENERATOR
Figure 3. Schematic - Stator Windings
DANGER! DO NOT WORK WITH SOLVENTS
CAUTION! Some generators use epoxy or
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Section INSULATION RESISTANCE
Figure 1. Stator Leads
Section COMPONENTS TESTING
STATOR ASSEMBLY
INTRODUCTION
Section COMPONENTS TESTING
STATOR ASSEMBLY CONTINUED
Figure 2. Schematic- Stator Windings
Figure 3. Battery Charge Windings and Rectifier
TESTING THE BATTERY CHARGE CIRCUIT
Figure 4. Battery Charge Circuit
Section COMPONENTS TESTING
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Section COMPONENTS TESTING
CONSTRUCTION
Section CONTROL PANEL
COMPONENTS
Figure 1. Exploded View of Control Panel
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Section CONTROL PANEL
GENERAL
Section SHEET METAL
Impact Plus Generator
Section SHEET METAL
EXPLODED VIEW OF SHEET METAL GASOLINE UNITS
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TO CARBURETOR
Section SHEET METAL
PARTS LIST FOR SHEET METAL GASOLINE UNITS
DESCRIPTION
DESCRIPTION
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EXPLODED VIEW OF SHEET METAL LP UNITS
Section SHEET METAL
Section SHEET METAL
PARTS LIST FOR SHEET METAL GASOLINE UNITS
DESCRIPTION
DESCRIPTION
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Section SHEET METAL
PART ENGINE MECHANICAL
2.3 PISTON, RINGS, CONNECTING ROD 2.4 CRANKSHAFT & CAMSHAFT
2.1 GENERAL INFORMATION 2.2 VALVE TRAIN
COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS
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Section GENERAL INFORMATION
Figure 3. Power Stroke Figure 4. Exhaust Stroke
4-CYCLE ENGINE THEORY
Figure 1. Intake Stroke Figure 2. Compression Stroke
RECOMMENDED ENGINE OIL
RECOMMENDED FUELS
NOTE DO NOT USE GASOLINE CONTAINING METHANOL
NOTE DO NOT MIX OIL WITH THE GASOLINE
STORAGE INSTRUCTIONS
THE UNIT IS NOW READY FOR SERVICE
ENGINE TUNE-UP
Section GENERAL INFORMATION
Section GENERAL INFORMATION
NOTE 1- Item 36 Includes valve seats and guides
EXPLODED VIEW OF ENGINE LONG BLOCK
DESCRIPTION
VALVE TRAIN COMPONENTS
Section VALVE TRAIN
VALVE COMPONENTS REMOVAL
Figure 1. Valve Train Components
DANGER! ALWAYS WEAR SAFETY GLASSES WHEN REMOVING THE VALVE SPRINGS
VALVE SERVICE
Figure 4. Cylinder Head Removal
Figure 5. Removal of Valve Spring
Figure 11. Installation of Intake and Exhaust Valves
VALVE COMPONENTS INSTALLATION
Figure 8. Valve Guides
Figure 10. Valve Tappet
ADJUSTING VALVE CLEARANCE
VALVE COMPONENTS INSTALLATION CONTINUED
Figure 12. Installing Valve Spring Washers
Figure 14. Install Rocker Arm & Pivot Ball stud
Figure 16. Adjusting Valve Clearance
ROCKER ARM COVER INSTALLATION
Figure 18. Rocker Arm Cover Installation
Figure 17. Tightening Pivot Ball Jam Nut
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Section VALVE TRAIN
Figure 1. Piston, Rings and Connecting Rod
Section PISTON, RINGS, CONNECTING ROD
OVERSIZE PISTON & RINGS
PRIOR TO REMOVAL
Figure 4. Piston Minor Diameter
PISTON RINGS
Figure 5. Piston Major Diameter
Figure 6. Ring to Groove Side Clearance
ASSEMBLY AND INSTALLATION
CONNECTING ROD
Figure 9. Connecting Rod
Figure 7. Ring Locations in Piston Grooves
Section PISTON, RINGS, CONNECTING ROD
CYLINDER SERVICE
Figure 10. Match Marks on Rod and Cap
CRANKCASE COVER REMOVAL
Section CRANKSHAFT AND CAMSHAFT
CAMSHAFT REMOVAL
CRANKSHAFT REMOVAL
CRANKSHAFT INSPECTION
CAMSHAFT INSPECTION
Figure 4. Points to Check on Camshaft
Figure 5. Points to Check on Crankshaft
INSTALLING THE CAMSHAFT
INSTALLING THE CRANKSHAFT
COMPRESSION RELEASE MECHANISM
Figure 6. Bearing Bore in Crankcase Cover
Figure 10. Alignment of Timing Marks
Figure 9. Timing Mark on Crankshaft Gear
Section CRANKSHAFT AND CAMSHAFT
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PART GASOLINE FUEL SYSTEM
AIR CLEANER & AIR INTAKE
INTRODUCTION TO FUEL SYSTEM
FILTER & FUEL PUMP
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RECOMMENDED FUEL
Section INTRODUCTION TO FUEL SYSTEM
EVAPORATION CONTROL SYSTEMS
DANGER! ATTEMPTING TO WELD OR BRAZE
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Figure 2. Typical Gasoline Fuel System
Section INTRODUCTION TO FUEL SYSTEM
AIR CLEANER
Section AIR CLEANER AND INTAKE
Figure 1. Engine Air Cleaner
AIR INTAKE
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Section AIR CLEANER AND INTAKE
FUEL FILTER
Section FUEL FILTER AND FUEL PUMP
FUEL PUMP
Figure 1. Fuel Filter Typical
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Section FUEL FILTER AND FUEL PUMP
GENERAL INFORMATION
Section CARBURETOR
DESCRIPTION
CARBURETOR OPERATION
CLEANING AND INSPECTION
CARBURETOR DISASSEMBLY
Figure 3. Carburetor Exploded View
Section CARBURETOR
THROTTLE LINKAGE ADJUSTMENT
ADJUSTMENT
Figure 5. Adjusting Throttle Linkage
ENGINE SPEED
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Figure 6. Carburetor Removal
Section CARBURETOR
Figure 2. Choke Adjustment
OPERATIONAL CHECK AND ADJUSTMENT
Section AUTOMATIC CHOKE
OPERATION
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Section AUTOMATIC CHOKE
Section SPEED CONTROL SYSTEM
STEPPER MOTOR PROBLEMS
A6060 CIRCUIT BOARD
Figure 1. Speed Control System
Section SPEED CONTROL SYSTEM
TESTING THE STEPPER MOTOR
Figure 2. The Stepper Motor Connector Figure 3. The Stepper Motor
PART GASEOUS FUEL SYSTEM
Air Cleaner & Air Intake Section Speed Control System Section
4.1 INTRODUCTION TO FUEL SYSTEM 4.2 SHUTOFF VALVE & REGULATOR
4.3 CARBURETOR
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FUEL SYSTEM COMPONENTS
ADVANTAGES OF GASEOUS FUELS
VAPOR WITHDRAWAL
IMPORTANT CONSIDERATIONS
EXCESS FLOW VALVE
FUEL SUPPLY LINES
IMPORTANT CONSIDERATIONS CONTINUED
Figure 1. A Typical LP Gas Fuel System
Figure 2. Gas Carburetion Diagram
LEAKAGE TESTING
GASEOUS CARBURETION
DANGER! DO NOT USE FLAME TO CHECK
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Section INTRODUCTION TO FUEL SYSTEM
TESTING THE FUEL LOCKOFF SOLENOID
ADJUSTMENTS
DANGER! DO NOT ATTEMPT TO ADJUST
Section SHUTOFF VALVE AND REGULATOR
If battery voltage is NOT Indicated, a problem exists In the DC
If battery voltage is Indicated but the solenoid does NOT ener
Section SHUTOFF VALVE AND REGULATOR
RESULTS OF TEST
DISASSEMBLY AND REASSEMBLY
CARBURETOR ADJUSTMENT
CARBURETION
Figure 1. LP Gas Carburetor
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Section CARBURETOR
5.1 ENGINE OIL SYSTEM 5.2 ENGINE COOLING SYSTEM
PART ENGINE OIL COOLING SYSTEM
COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS
Series Impact 36 Plus
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Section ENGINE OIL SYSTEM
Figure 1. Oil System Diagram
INTRODUCTION TO OIL SYSTEM
OIL PUMP
OIL PUMP CONTINUED
BREATHER ASSEMBLY
CRANKSHAFT OIL SEALS
PRESSURE RELIEF VALVE
OIL SUMP
Figure 6. Breather Assembly
OIL FILTER SUPPORT
Figure 7. Oil Filter Support
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Section ENGINE OIL SYSTEM
GENERATOR AIR FLOW
Section ENGINE COOLING SYSTEM
COOLING AIR INLET OPENINGS
Figure 1 - Air Flow Through Engine-Generator
CAUTION Do not install the inverter in the
TESTING THE INSTALLATION
COMPENSATING FOR RESTRICTIONS
INVERTER LOCATION
PART ENGINE ELECTRICAL SYSTEM
ENGINE SHUTDOWN FEATURES
ENGINE DC CONTROL SYSTEM
A6060 CIRCUIT BOARD
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GENERAL
Figure 1. Schematic- Engine DC Control System
Section ENGINE DC CONTROL SYSTEM
NOTE Also see Section 3.5, AUTOMATIC
HOW IT WORKS
CHOKE and Section 6.2, A6060 CIRCUIT
BOARD
battery is connected
WIRE
NOTE 1 - See SHUTDOWN FEATURES” In Section 6.5 Page
Section 6.2 A6060 CIRCUIT BOARD
CIRCUIT BOARD CONNECTIONS CONTINUED
Section A6060 CIRCUIT BOARD
Figure 1. Schematic - Cranking Circuit
BATTERY
Section ENGINE CRANKING SYSTEM
CABLE LENGTH
START-RUN-STOP SWITCH SW1
BATTERY CONTINUED
STARTER CONTACTOR
Section ENGINE CRANKING SYSTEM
Figure 3. Starter Contactor
STARTER MOTOR
Figure 4. Starter Motor
Section ENGINE CRANKING SYSTEM
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Section ENGINE CRANKING SYSTEM
Figure 1. Ignition Cage Assembly
IGNITION CAGE ASSEMBLY
Figure 3. Ignition Sensor Schematic
Section ENGINE IGNITION SYSTEM
Figure 7. Ignition System Diagram
TESTING THE SYSTEM
Figure 6. Setting Spark Plug Gap
IGNITION MODULE CONTINUED
Warning! Do NOT use a screwdriver to test for
Figure 8. Testing for Spark
spark. Personal injury or damage to equip- ment may result
Figure 9. Checking Engine Miss
Figure 12. Testing Ignition Sensor
TESTING THE SYSTEM CONTINUED
Figure 13. Testing Ignition Coil Figure 14. Testing Ignition Module
Note Only one spark should be observed upon initial cranking
OIL PRESSURE SWITCH
Section SHUTDOWN FEATURES
OIL TEMPERATURE SWITCH
Figure 3. Testing the Oil Temperature Switch
Section SHUTDOWN FEATURES
ADDITIONAL SHUTDOWN FEATURES
Figure 1. Remote Panel Plug-In Receptacle
Section OPTIONAL REMOTE PANEL
Figure 2. Optional Remote Panel Models 004057 and
GENERAL
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Section OPTIONAL REMOTE PANEL
7.2 ENGINE DC CONTROL SYSTEM/ AC TROUBLESHOOTING
PART TROUBLE SHOOTING
7.1 GENERATOR & SPEED CONTROL
COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS
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TROUBLESHOOTING REFERENCE CHART
Section GENERATOR & SPEED CONTROL SYSTEM
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Section GENERATOR & SPEED CONTROL SYSTEM
INTRODUCTION
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
PROBLEM 1- PRIMING FUNCTION DOES NOT WORK
PROBLEM 3 - ENGINE CRANKS BUT WILL NOT START
PROBLEM 2 - ENGINE WILL NOT CRANK
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
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Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
PROBLEM 3 - ENGINE CRANKS BUT WILL NOT START CONTINUED
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PROBLEM 4 - ENGINE STARTS HARD AND RUNS ROUGH
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
PROBLEM 5 - ENGINE STARTS THEN SHUTS DOWN AFTER A FEW SECONDS
SHUTS DOWN TEST TEST INVERTER Pg FAIL REPLACE INVERTER
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PROBLEM 7 - GENERATOR CIRCUIT BREAKER TRIPS / NO AC VOLTAGE
PROBLEM 6 - GENERATOR DOESN’T PULL FULL LOAD
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
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PROBLEM 9 - GENERATOR LOSES AC POWER THEN SHUTS DOWN
PROBLEM 8 - ENGINE SHUTS DOWN UNDER LOAD
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
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Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
PROBLEM 10 - NO AC OUTPUT
12-WIRE
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PROBLEM 10 - NO AC OUTPUT CONTINUED
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
TEST 2- CHECK POWER TO PRIMER SWITCH
TEST 3- CHECK POWER TO FUEL PUMP
Figure 2. Primer Switch
TEST 1- CHECK 7.5 AMP FUSE
TEST 7- CHECK WIRE 14A TO FUEL PUMP
TEST 6- TEST PRIMER SWITCH
TEST 8- CHECK POWER SUPPLY TO STARTER MOTOR
TEST 4- CHECK BATTERY/BATTERY CIRCUIT
TEST 10- CHECK A6060 CIRCUIT BOARD POWER SUPPLY
TEST 9- CHECK WIRE 56 POWER TO STARTER CONTACTOR
Figure 5. Starter Contactor
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
Figure 7. Start-Stop Switch
TEST 12- TEST START-STOP SWITCH
TEST 11- TEST STARTER CONTACTOR
TEST 13- CHECK FUEL SUPPLY
TEST 17- CHECK IGNITION POWER SUPPLY
TEST 21 - CHECK A6060 CIRCUIT BOARD OUTPUT TO WIRE
Figure 9. Ignition Module & 4-Tab Connector
TEST 18- CHECK IGNITION SENSOR
TEST 22-TEST AUTOMATIC CHOKE
TEST 23- CHECK CARBURETION
TEST 24- CHECK ENGINE
Figure 10. Receptacle J2
TEST 26- TEST OIL PRESSURE SWITCH
TEST 27- TEST OIL TEMPERATURE SWITCH
Note Cap the DC Link wires with a wire nut for safety
TEST 28 - DC LINK VOLTAGE TEST
TEST 29 - 12 POSITION HARNESS CONTINUITY TEST
TEST 30 - 12 POSITION HARNESS SIGNALS TEST
Note Fluke 87 true RMS meter used in test
Figure 10 Free End of 12 Position Harness
Figure 11. 12 Position Connector on Inverter
STATOR TESTS TEST 32 - POWER SUPPLY WINDING TEST
Pin 4 Wire #14
TEST 31 - STATIC TESTS ON INVERTER
TEST 34 -STATOR RESISTANCE VALUES
TEST 36 - AC POWER WINDING TEST AC1/AC2/SL1/SL2
TEST 35 - BRIDGE RECTIFIER TEST
Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
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Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
General Specifications
PART SPECIFICATIONS AND CHARTS
Electrical Schematic
Wiring Diagram
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Part
ENGINE SPEEDS AND VOLTAGE SPECIFICATIONS
NOMINAL RESISTANCES OF GENERATOR WINDINGS
LOAD %
ELECTRICAL SCHEMATIC DRAWING NO. 0D4947-B
Part SPECIFICATIONS & CHARTS
1 OF
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Part SPECIFICATIONS & CHARTS
WIRING DIAGRAM DRAWING NO. 0D4947-B
2 OF
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MODEL
GENERAL SPECIFICATIONS
GV-220
Part SPECIFICATIONS & CHARTS
CRANKCASE ASSEMBLY
SPECIFICATIONS & CHARTS
CRANKCASE COVER ASSEMBLY
Later model small frame GN engines have no crankshaft sleeve bearing
CRANKSHAFT
CONNECTING ROD ASSEMBLY
PISTON
Part SPECIFICATIONS & CHARTS
MODEL
PISTON CONTINUED
Part SPECIFICATIONS & CHARTS
OIL PUMP
CAMSHAFT ASSEMBLY
NOTE 2 Measure pump tip clearance on shaft in crankcase cover
Part SPECIFICATIONS & CHARTS
Part
SPECIFICATIONS & CHARTS
MODEL
MODEL
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MAJOR FEATURES AND DIMENSIONS GENERATOR
Part SPECIFICATIONS & CHARTS
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MAJOR FEATURES AND DIMENSIONS INVERTER
Part SPECIFICATIONS & CHARTS
