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Generac Power Systems 940, 941 VALVE COMPONENTS INSTALLATION (CONTINUED), ADJUSTING VALVE CLEARANCE

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Section 2.2

VALVE TRAIN

VALVE COMPONENTS INSTALLATION(CONTINUED)

3. Install the valve spring washers, valve springs and valve spring

retainers over the valve guides.

a.Hold the valve with your fingers and use your

thumbs to compress the spring.

b.When the spring is compressed sufficiently,

slide the spring retainer small opening over the

valve stem.

c.With the smaller retainer opening around the

valve stem, release the spring.

Figure 12. Installing Valve Spring Washers

4. After both valves have been retained in the cylinder head, posi-

tion a new head gasket and install the cylinder head.

NOTE: The head gasket is coated with a special

substance for beer sealing. The gasket must be

free of nicks, scratches and other defects for bet-

ter sealing.

5.Install cylinder head bolts. Tighten the head bolts in the

sequence shown to the recommended tightness.

TIGHTENING TORQUE

CYLINDER HEAD

GV-220: 29 foot-pounds

Figure 13. Head Bolts Tightening Sequence

6. Place the push rod guide plate into position on the head. Then,

install the rocker arm and the pivot ball stud. The rocker arm

jam nut must be on far enough to hold the guide plate In posi-

tion.

NOTE: Do NOT adjust valve clearance at this time.

This will be done later.

Figure 14. Install Rocker Arm & Pivot Ball stud

7. install the push rod with either end against the tappet.

a.Place the push rod between the guide plate

tabs.

b.Place the rocker arm socket onto end of push

rod.

c.Alignment is correct when push rod ball rests In

the rocker arm socket.

NOTE: The pivot ball stud will be tightened when

the valve clearance Is adjusted. After valve clear-

ance has been adjusted, the rocker arm cover will

be Installed.

Figure 15. Push Rod Installation

ADJUSTING VALVE CLEARANCE

When adjusting valve clearance, the engine should

be at room temperature and the piston should be at

top dead center (TDC) of Its compression stroke

(both valves closed).

Page 2.2-4

Contents

Main SAFETY NOTICE TO USERS OF THIS MANUAL REPLACEMENT PARTS Page Page Page Page MAGNETISM Figure 1. Magnetic Lines of Force ELECTROMAGNETIC FIELDS Figure 2. The Right Hand Rule ELECTROMAGNETIC INDUCTION ALTERNATING CURRENT Figure 4. Operation of a Simple Generator ELECTRICAL UNITS Figure 5. Alternating Current Sine Wave Figure 6. Electrical Units OHM'S LAW VOLTS = AMPERES x OHMS Figure 7. AMPERES = VOLTS OHMS OHMS = VOLTS AMPERES Figure 9. Capacitive Reactance Figure 10. Block Diagram of the Impact 36 Plus System WHY VARIABLE SPEED CONTROL? Page Section 1.2 MAJOR GENERATOR COMPONENTS UPPER FAN HOUSING UPPER COOLING FAN PERMANENT MAGNET ROTOR Section 1.2 MAJOR GENERATOR COMPONENTS ROTOR HUB STATOR RETAINING RING STATOR ASSEMBLY STATOR ADAPTER Page Page Section 1.3 OPERATIONALANALYSIS OPERATIONAL DESCRIPTION Figure 1. Block Diagram- A Generator System Section 1.3 OPERATIONALANALYSIS OPERATIONAL DESCRIPTION (CONTINUED) DIRT AND MOISTURE INSULATION RESISTANCE TESTERS Figure 1. One Kind of Hi-Pot Tester STATOR LEADS Figure 2. Stator Leads TEST ALL STATOR WINDINGS TO GROUND TEST FOR SHORTS BETWEEN WINDINGS RESULTS OF TESTS CLEANING THE GENERATOR Figure 3. Schematic- Stator Windings DRYING THE GENERATOR Page STATOR ASSEMBLY Figure 1. Stator Leads STATOR ASSEMBLY (CONTINUED) Figure 2. Schematic- Stator Windings TESTING THE BATTERY CHARGE CIRCUIT Figure 3. Battery Charge Windings and Rectifier Figure 4. Battery Charge Circuit Page Section 1.6 CONTROL PANEL CONSTRUCTION Figure 1. Exploded View of Control Panel COMPONENTS Page 1.6-1 Page Impact Plus Generator Page Page Page PARTS LIST FOR SHEET METAL (GASOLINE UNITS) Page Page Page 4-CYCLE ENGINE THEORY Figure 1. Intake Stroke Figure 2. Compression Stroke Figure 3. Power Stroke Figure 4. Exhaust Stroke RECOMMENDED FUELS NOTE: DO NOT USE GASOLINE CONTAINING METHANOL. NOTE: DO NOT MIX OIL WITH THE GASOLINE. RECOMMENDED ENGINE OIL STORAGE INSTRUCTIONS THE UNIT IS NOW READY FOR SERVICE. ENGINE TUNE-UP NOTE 2:- Use a Champion RC12YC (or equivalent) spark plug with gap set to 0.030 inch (0.76mm). EXPLODED VIEW OF ENGINE LONG BLOCK NOTE 1:- Item 36 Includes valve seats and guides. VALVE TRAIN COMPONENTS VALVE COMPONENTS REMOVAL Figure 4. Cylinder Head Removal Figure 5. Removal of Valve Spring VALVE SERVICE Figure 7. Valve Seat VALVE COMPONENTS INSTALLATION VALVE COMPONENTS INSTALLATION (CONTINUED) ADJUSTING VALVE CLEARANCE Figure 16. Adjusting Valve Clearance Figure 17. Tightening Pivot Ball Jam Nut Figure 18. Rocker Arm Cover Installation ROCKER ARM COVER INSTALLATION Page OVERSIZE PISTON & RINGS PRIOR TO REMOVAL REMOVAL PISTON Figure 4. Piston Minor Diameter PISTON RINGS Figure 7. Ring Locations in Piston Grooves Figure 8. Ring End Gap CONNECTING ROD Figure 9. Connecting Rod ASSEMBLY AND INSTALLATION Figure 10. Match Marks on Rod and Cap CYLINDER SERVICE CRANKCASE COVER REMOVAL Figure 1. Crankcase Cover Removal CRANKSHAFT REMOVAL CAMSHAFT REMOVAL Figure 2. Camshaft Removal CAMSHAFT INSPECTION Figure 4. Points to Check on Camshaft CRANKSHAFT INSPECTION Figure 5. Points to Check on Crankshaft Figure 7. Bearing Bore in Crankcase Cover COMPRESSION RELEASE MECHANISM Figure 7. Compression Release Mechanism on Camshaft Figure 8. Measuring Compression Release Lift INSTALLING THE CRANKSHAFT INSTALLING THE CAMSHAFT Page Page Page Section 3.1 RECOMMENDED FUEL Figure 1. Sharing a Fuel Supply Tank EVAPORATION CONTROL SYSTEMS Page Section 3.2 AIR CLEANER AND INTAKE AIR CLEANER Figure 1. Engine Air Cleaner AIR INTAKE Figure 2. Air Intake Components Page Section 3.3 FUEL FILTER AND FUEL PUMP FUEL FILTER Figure 2. Electric Fuel Pump Figure 1. Fuel Filter (Typical) FUEL PUMP Page GENERAL INFORMATION Figure 1. Carburetor CARBURETOR OPERATION Figure 2. Carburetor Sectional View CARBURETOR DISASSEMBLY CLEANING AND INSPECTION Figure 3. Carburetor Exploded View ADJUSTMENT ENGINE SPEED THROTTLE LINKAGE ADJUSTMENT Figure 4. Set Gap Between Stop Tab and Stop Block Figure 5. Adjusting Throttle Linkage Page Section 3.5 AUTOMATIC CHOKE Figure 1. Choke Solenoid Parts OPERATION OPERATIONAL CHECK AND ADJUSTMENT Figure 2. Choke Adjustment Page Section 3.6 SPEED CONTROL SYSTEM A6060 CIRCUIT BOARD Figure 1. Speed Control System STEPPER MOTOR PROBLEMS Section 3.6 SPEED CONTROL SYSTEM TESTING THE STEPPER MOTOR Figure 2. The Stepper Motor Connector Figure 3. The Stepper Motor Page Page GENERAL INFORMATION ADVANTAGES OF GASEOUS FUELS FUEL SYSTEM COMPONENTS VAPOR WITHDRAWAL IMPORTANT CONSIDERATIONS IMPORTANT CONSIDERATIONS (CONTINUED) FUEL SUPPLY LINES EXCESS FLOW VALVE GASEOUS CARBURETION Figure 2. Gas Carburetion Diagram LEAKAGE TESTING Page Section 4.2 SHUTOFF VALVE AND REGULATOR Figure 1. Shutoff Valve & Regulator ADJUSTMENTS THE LP GAS REGULATOR Figure 2. LP Gas Regulator Section 4.2 SHUTOFF VALVE AND REGULATOR RESULTS OF TEST: Figure 3. Fuel Lockoff Solenoid Page Page Page Page INTRODUCTION TO OIL SYSTEM OIL FLOW Figure 1. Oil System Diagram OIL PICKUP SCREEN OIL PUMP OIL PUMP (CONTINUED) Figure 3. Oil Pump Check Points Figure 4. Crankshaft Oil Seals CRANKSHAFT OIL SEALS PRESSURE RELIEF VALVE OIL SUMP OIL FILTER SUPPORT Figure 7. Oil Filter Support Page Section 5.2 ENGINE COOLING SYSTEM GENERATOR AIR FLOW COOLING AIR INLET OPENINGS Section 5.2 ENGINE COOLING SYSTEM Figure 3 Suspended Mount Inlet Door Figure 5 Air Inlet in Vehicle Skirt Figure 4. Ductwork COMPENSATING FOR RESTRICTIONS Page Page Section 6.1 ENGINE DC CONTROL SYSTEM Figure 1. Schematic- Engine DC Control System HOW IT WORKS NOTE: Also see Section 3.5, "AUTOMATIC CHOKE" and Section 6.2, "A6060 CIRCUIT BOARD". Section 6.2 A6060 CIRCUIT BOARD Figure 1. A6060 Circuit Board CIRCUIT BOARD CONNECTIONS Figure 2. Receptacle J2 NOTE 1: - See "SHUTDOWN FEATURES In Section 6.5 (Page 6.5-1). Section 6.2 A6060 CIRCUIT BOARD CIRCUIT BOARD CONNECTIONS (CONTINUED) Figure 1. Schematic - Cranking Circuit BATTERY BATTERY (CONTINUED) START-RUN-STOP SWITCH (SW1) Figure 2. STARTER CONTACTOR Figure 3. Starter Contactor STARTER MOTOR Figure 4. Starter Motor Page IGNITION CAGE ASSEMBLY NOTE: Also refer to "Permanent Magnet Rotor" in Section 1.2 (Page 1.2-1). Figure 1. Ignition Cage Assembly IGNITION SENSOR Figure 2. Ignition Sensor IGNITION MODULE (CONTINUED) Figure 4. Ignition Module Figure 6. Setting park Plug Gap IGNITION COIL Figure 5. Ignition oil Figure 8. Testing for Spark Figure 9. Checking Engine Miss Figure 10. TESTING THE SYSTEM (CONTINUED) Note: Only one spark should be observed upon initial cranking. Figure 12. Testing Ignition Sensor Figure 13. Testing Ignition Coil Figure 14. Ignition Module Section 6.5 SHUTDOWN FEATURES OIL PRESSURE SWITCH Figure 1. Engine Protective Circuit OIL TEMPERATURE SWITCH Figure 2. Engine Protective Devices Section 6.5 SHUTDOWN FEATURES ADDITIONAL SHUTDOWN FEATURES Section 6.6 OPTIONAL REMOTE PANEL REMOTE PANEL CABLES Figure 2. Model 9042 Remote Panel Figure 1. Remote Panel Receptacle Figure 3. Model 9043 Remote Panel Page Page Page Section 7.1 GENERATOR & SPEEDCONTROL SYSTEM TROUBLESHOOTING REFERENCE CHART Page 7.1-1 Page PROBLEM 1- PRIMING FUNCTION DOES NOT WORK Page Page Page Page Page Page Page Page TEST 1- CHECK 7.5 AMP FUSE Figure 1. 7.5 Amp Fuse TEST 2- CHECK POWER TO PRIMER SWITCH Figure 2. Primer Switch TEST 3- CHECK POWER TO FUEL PUMP TEST 4- CHECK BATTERY/BATTERY CIRCUIT TEST 5- TEST FUEL PUMP TEST 6- TEST PRIMER SWITCH TEST 7- CHECK WIRE 14A TO FUEL PUMP TEST 8- CHECK POWER SUPPLY TO STARTER MOTOR TEST 9- CHECK WIRE 56 POWER TO STARTER CONTACTOR Figure 5. Starter Contactor TEST 10- CHECK A6060 CIRCUIT BOARD POWER SUPPLY TEST 11- TEST STARTER CONTACTOR TEST 12- TEST START-STOP SWITCH Figure 7. Start-Stop Switch TEST 13- CHECK FUEL SUPPLY TEST 14- CHECK FUEL FILTER TEST 17- CHECK IGNITION POWER SUPPLY Figure 9. Ignition Module & 4-Tab Connector TEST 18- CHECK IGNITION SENSOR TEST 19- CHECK IGNITION COIL TEST 20- TEST IGNITION MODULE TEST 22-TEST AUTOMATIC CHOKE TEST 23- CHECK CARBURETION TEST 24- CHECK ENGINE TEST 26- TEST OIL PRESSURE SWITCH TEST 27- TEST OIL TEMPERATURE SWITCH TEST 28 - DC LINK VOLTAGE TEST TEST 29 - 9-PIN WIRE HARNESS/ 2-PIN WIRE HARNESS CONTINUITY TEST - TEST 30 9-WIRE HARNESS SIGNALS TEST Note: Cap the DC Link wires with a wire nut for safety. TEST 31 - STATIC TESTS ON INVERTER Figure 11. 9-Pin Connector on Inverter *NTC thermistor; if inverter is hot, resistance may be several kOhm lower. STATOR TESTS TEST 32 - POWER SUPPLY WINDING TEST TEST 33 - TIMING WINDING TEST TEST 34 -STATOR RESISTANCE VALUES TEST 35 - BRIDGE RECTIFIER TEST TEST 36 - AC POWER WINDING TEST AC1/AC2/SL1/SL2 Page Page Page NOMINAL RESISTANCES OF GENERATOR WINDINGS ENGINE SPEEDS AND VOLTAGE SPECIFICATIONS Page Page CRANKSHAFT END PLAY VALVE TRAIN GENERAL SPECIFICATIONS CRANKCASE ASSEMBLY *Later model small frame GN engines have no crankshaft sleeve bearing. CRANKCASE COVER ASSEMBLY CRANKSHAFT CONNECTING ROD ASSEMBLY PISTON PISTON (CONTINUED) *NOTE 1: Measure end gap with ring pushed down in cylinder to depth of 2.75 inches CAMSHAFT ASSEMBLY OIL PUMP *NOTE 2: Measure pump tip clearance on shaft in crankcase cover. OIL PUMP (CONTINUED) COMPRESSION PRESSURE TORQUE SPECIFICATIONS