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Generac Power Systems 940-2, 941-2 service manual Section COMPONENTS TESTING, Page

Models: 941-2 940-2

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Section 1.5

COMPONENTS TESTING

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Generac Power Systems 940-2, 941-2 service manual Section COMPONENTS TESTING, Page

Contents

SERIES IMPACT 36 PLUS Models 940-2SERVICE MANUAL P. O. Box 297 Whitewater, WINOTICE TO USERS OF THIS MANUAL SAFETYREPLACEMENT PARTS TROUBLESHOOTING SERVICE MANUALTABLE OF CONTENTS SPECIFICATIONS & CHARTSPage COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS COMPONENTS TESTINGPART GENERAL INFORMATION Series Impact 36 PlusPage ELECTROMAGNETIC FIELDS Section GENERATOR FUNDAMENTALSMAGNETISM ELECTROMAGNETIC INDUCTIONFigure 4. Operation of a Simple Generator ALTERNATING CURRENTELECTRICAL UNITS Figure 5. Alternating Current Sine WaveFigure 6. Electrical Units OHMS LAWREACTANCE IN AC CIRCUITS AMPERES = VOLTSOHMSSection GENERATOR FUNDAMENTALS Figure 10. Block Diagram of the Impact 36 Plus SystemFigure 9. Capacitive Reactance CAPACITIVE REACTANCEWHY VARIABLE SPEED CONTROL? Section GENERATOR FUNDAMENTALSSection GENERATOR FUNDAMENTALS PageSection MAJOR GENERATOR COMPONENTS UPPER FAN HOUSINGFigure 2 Permanent Magnet Rotor Assembly INTRODUCTIONSTATOR RETAINING RING STATOR ASSEMBLYROTOR HUB STEPPER MOTORPage Figure 5. Schematic- Stator WindingsSection MAJOR GENERATOR COMPONENTS Section MAJOR GENERATOR COMPONENTS PageGENERAL Figure 1. Block Diagram- A Generator SystemSection OPERATIONAL ANALYSIS OPERATIONAL DESCRIPTIONOPERATIONAL DESCRIPTION CONTINUED Section OPERATIONAL ANALYSISDIRT AND MOISTURE CAUTION! When using a Megohmmeter orSection INSULATION RESISTANCE INSULATION RESISTANCE TESTERSTEST FOR SHORTS BETWEEN WINDINGS CLEANING THE GENERATORTEST ALL STATOR WINDINGS TO GROUND RESULTS OF TESTSDANGER! DO NOT WORK WITH SOLVENTS Figure 3. Schematic - Stator WindingsDRYING THE GENERATOR CAUTION! Some generators use epoxy orSection INSULATION RESISTANCE PageSTATOR ASSEMBLY Section COMPONENTS TESTINGFigure 1. Stator Leads INTRODUCTIONSection COMPONENTS TESTING STATOR ASSEMBLY CONTINUEDFigure 2. Schematic- Stator Windings Figure 4. Battery Charge Circuit TESTING THE BATTERY CHARGE CIRCUITFigure 3. Battery Charge Windings and Rectifier Section COMPONENTS TESTINGSection COMPONENTS TESTING PageCOMPONENTS Section CONTROL PANELCONSTRUCTION Figure 1. Exploded View of Control PanelSection CONTROL PANEL PageGENERAL Section SHEET METALImpact Plus Generator Page EXPLODED VIEW OF SHEET METAL GASOLINE UNITSSection SHEET METAL TO CARBURETORDESCRIPTION PARTS LIST FOR SHEET METAL GASOLINE UNITSSection SHEET METAL DESCRIPTIONPage EXPLODED VIEW OF SHEET METAL LP UNITSSection SHEET METAL DESCRIPTION PARTS LIST FOR SHEET METAL GASOLINE UNITSSection SHEET METAL DESCRIPTIONSection SHEET METAL Page2.1 GENERAL INFORMATION 2.2 VALVE TRAIN 2.3 PISTON, RINGS, CONNECTING ROD 2.4 CRANKSHAFT & CAMSHAFTPART ENGINE MECHANICAL COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORSPage 4-CYCLE ENGINE THEORY Figure 3. Power Stroke Figure 4. Exhaust StrokeSection GENERAL INFORMATION Figure 1. Intake Stroke Figure 2. Compression StrokeNOTE DO NOT USE GASOLINE CONTAINING METHANOL RECOMMENDED FUELSRECOMMENDED ENGINE OIL NOTE DO NOT MIX OIL WITH THE GASOLINEENGINE TUNE-UP THE UNIT IS NOW READY FOR SERVICESTORAGE INSTRUCTIONS Section GENERAL INFORMATIONEXPLODED VIEW OF ENGINE LONG BLOCK NOTE 1- Item 36 Includes valve seats and guidesSection GENERAL INFORMATION DESCRIPTIONVALVE COMPONENTS REMOVAL Section VALVE TRAINVALVE TRAIN COMPONENTS Figure 1. Valve Train ComponentsFigure 4. Cylinder Head Removal VALVE SERVICEDANGER! ALWAYS WEAR SAFETY GLASSES WHEN REMOVING THE VALVE SPRINGS Figure 5. Removal of Valve SpringFigure 8. Valve Guides VALVE COMPONENTS INSTALLATIONFigure 11. Installation of Intake and Exhaust Valves Figure 10. Valve TappetFigure 12. Installing Valve Spring Washers VALVE COMPONENTS INSTALLATION CONTINUEDADJUSTING VALVE CLEARANCE Figure 14. Install Rocker Arm & Pivot Ball studFigure 18. Rocker Arm Cover Installation ROCKER ARM COVER INSTALLATIONFigure 16. Adjusting Valve Clearance Figure 17. Tightening Pivot Ball Jam NutSection VALVE TRAIN PageOVERSIZE PISTON & RINGS Section PISTON, RINGS, CONNECTING RODFigure 1. Piston, Rings and Connecting Rod PRIOR TO REMOVALFigure 5. Piston Major Diameter PISTON RINGSFigure 4. Piston Minor Diameter Figure 6. Ring to Groove Side ClearanceFigure 9. Connecting Rod CONNECTING RODASSEMBLY AND INSTALLATION Figure 7. Ring Locations in Piston GroovesSection PISTON, RINGS, CONNECTING ROD CYLINDER SERVICEFigure 10. Match Marks on Rod and Cap CAMSHAFT REMOVAL Section CRANKSHAFT AND CAMSHAFTCRANKCASE COVER REMOVAL CRANKSHAFT REMOVALFigure 4. Points to Check on Camshaft CAMSHAFT INSPECTIONCRANKSHAFT INSPECTION Figure 5. Points to Check on CrankshaftCOMPRESSION RELEASE MECHANISM INSTALLING THE CRANKSHAFTINSTALLING THE CAMSHAFT Figure 6. Bearing Bore in Crankcase CoverSection CRANKSHAFT AND CAMSHAFT Figure 9. Timing Mark on Crankshaft GearFigure 10. Alignment of Timing Marks PageINTRODUCTION TO FUEL SYSTEM AIR CLEANER & AIR INTAKEPART GASOLINE FUEL SYSTEM FILTER & FUEL PUMPPage EVAPORATION CONTROL SYSTEMS Section INTRODUCTION TO FUEL SYSTEMRECOMMENDED FUEL DANGER! ATTEMPTING TO WELD OR BRAZEPage Figure 2. Typical Gasoline Fuel SystemSection INTRODUCTION TO FUEL SYSTEM Figure 1. Engine Air Cleaner Section AIR CLEANER AND INTAKEAIR CLEANER AIR INTAKESection AIR CLEANER AND INTAKE PageFUEL PUMP Section FUEL FILTER AND FUEL PUMPFUEL FILTER Figure 1. Fuel Filter TypicalSection FUEL FILTER AND FUEL PUMP PageDESCRIPTION Section CARBURETORGENERAL INFORMATION CARBURETOR OPERATIONFigure 3. Carburetor Exploded View CARBURETOR DISASSEMBLYCLEANING AND INSPECTION Section CARBURETORFigure 5. Adjusting Throttle Linkage ADJUSTMENTTHROTTLE LINKAGE ADJUSTMENT ENGINE SPEEDPage Figure 6. Carburetor RemovalSection CARBURETOR Section AUTOMATIC CHOKE OPERATIONAL CHECK AND ADJUSTMENTFigure 2. Choke Adjustment OPERATIONSection AUTOMATIC CHOKE PageA6060 CIRCUIT BOARD STEPPER MOTOR PROBLEMSSection SPEED CONTROL SYSTEM Figure 1. Speed Control SystemSection SPEED CONTROL SYSTEM TESTING THE STEPPER MOTORFigure 2. The Stepper Motor Connector Figure 3. The Stepper Motor 4.1 INTRODUCTION TO FUEL SYSTEM 4.2 SHUTOFF VALVE & REGULATOR Air Cleaner & Air Intake Section Speed Control System SectionPART GASEOUS FUEL SYSTEM 4.3 CARBURETORPage VAPOR WITHDRAWAL ADVANTAGES OF GASEOUS FUELSFUEL SYSTEM COMPONENTS IMPORTANT CONSIDERATIONSIMPORTANT CONSIDERATIONS CONTINUED FUEL SUPPLY LINESEXCESS FLOW VALVE Figure 1. A Typical LP Gas Fuel SystemGASEOUS CARBURETION LEAKAGE TESTINGFigure 2. Gas Carburetion Diagram DANGER! DO NOT USE FLAME TO CHECKSection INTRODUCTION TO FUEL SYSTEM PageDANGER! DO NOT ATTEMPT TO ADJUST ADJUSTMENTSTESTING THE FUEL LOCKOFF SOLENOID Section SHUTOFF VALVE AND REGULATORSection SHUTOFF VALVE AND REGULATOR If battery voltage is Indicated but the solenoid does NOT enerIf battery voltage is NOT Indicated, a problem exists In the DC RESULTS OF TESTCARBURETION CARBURETOR ADJUSTMENTDISASSEMBLY AND REASSEMBLY Figure 1. LP Gas CarburetorSection CARBURETOR PageCOMPUTER CONTROLLED VARIABLE SPEED RV GENERATORS PART ENGINE OIL COOLING SYSTEM5.1 ENGINE OIL SYSTEM 5.2 ENGINE COOLING SYSTEM Series Impact 36 PlusPage INTRODUCTION TO OIL SYSTEM Figure 1. Oil System DiagramSection ENGINE OIL SYSTEM OIL PUMPCRANKSHAFT OIL SEALS BREATHER ASSEMBLYOIL PUMP CONTINUED PRESSURE RELIEF VALVEOIL FILTER SUPPORT Figure 6. Breather AssemblyOIL SUMP Figure 7. Oil Filter SupportSection ENGINE OIL SYSTEM PageCOOLING AIR INLET OPENINGS Section ENGINE COOLING SYSTEMGENERATOR AIR FLOW Figure 1 - Air Flow Through Engine-GeneratorCOMPENSATING FOR RESTRICTIONS TESTING THE INSTALLATIONCAUTION Do not install the inverter in the INVERTER LOCATIONENGINE DC CONTROL SYSTEM ENGINE SHUTDOWN FEATURESPART ENGINE ELECTRICAL SYSTEM A6060 CIRCUIT BOARDPage GENERAL Figure 1. Schematic- Engine DC Control SystemSection ENGINE DC CONTROL SYSTEM CHOKE and Section 6.2, A6060 CIRCUIT HOW IT WORKSNOTE Also see Section 3.5, AUTOMATIC BOARDNOTE 1 - See SHUTDOWN FEATURES” In Section 6.5 Page WIREbattery is connected Section 6.2 A6060 CIRCUIT BOARDSection A6060 CIRCUIT BOARD CIRCUIT BOARD CONNECTIONS CONTINUEDSection ENGINE CRANKING SYSTEM BATTERYFigure 1. Schematic - Cranking Circuit CABLE LENGTHSTARTER CONTACTOR BATTERY CONTINUEDSTART-RUN-STOP SWITCH SW1 Section ENGINE CRANKING SYSTEMFigure 4. Starter Motor STARTER MOTORFigure 3. Starter Contactor Section ENGINE CRANKING SYSTEMSection ENGINE CRANKING SYSTEM PageFigure 3. Ignition Sensor Schematic IGNITION CAGE ASSEMBLYFigure 1. Ignition Cage Assembly Section ENGINE IGNITION SYSTEMFigure 6. Setting Spark Plug Gap TESTING THE SYSTEMFigure 7. Ignition System Diagram IGNITION MODULE CONTINUEDspark. Personal injury or damage to equip- ment may result Figure 8. Testing for SparkWarning! Do NOT use a screwdriver to test for Figure 9. Checking Engine MissFigure 13. Testing Ignition Coil Figure 14. Testing Ignition Module TESTING THE SYSTEM CONTINUEDFigure 12. Testing Ignition Sensor Note Only one spark should be observed upon initial crankingOIL TEMPERATURE SWITCH Section SHUTDOWN FEATURESOIL PRESSURE SWITCH Figure 3. Testing the Oil Temperature SwitchADDITIONAL SHUTDOWN FEATURES Section SHUTDOWN FEATURESFigure 2. Optional Remote Panel Models 004057 and Section OPTIONAL REMOTE PANELFigure 1. Remote Panel Plug-In Receptacle GENERALSection OPTIONAL REMOTE PANEL Page7.1 GENERATOR & SPEED CONTROL PART TROUBLE SHOOTING7.2 ENGINE DC CONTROL SYSTEM/ AC TROUBLESHOOTING COMPUTER CONTROLLED VARIABLE SPEED RV GENERATORSPage Page TROUBLESHOOTING REFERENCE CHARTSection GENERATOR & SPEED CONTROL SYSTEM Section GENERATOR & SPEED CONTROL SYSTEM PageINTRODUCTION Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTINGPROBLEM 1- PRIMING FUNCTION DOES NOT WORK Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PROBLEM 2 - ENGINE WILL NOT CRANKPROBLEM 3 - ENGINE CRANKS BUT WILL NOT START PagePROBLEM 3 - ENGINE CRANKS BUT WILL NOT START CONTINUED Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTINGPage PROBLEM 4 - ENGINE STARTS HARD AND RUNS ROUGHSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING SHUTS DOWN TEST TEST INVERTER Pg FAIL REPLACE INVERTER PROBLEM 5 - ENGINE STARTS THEN SHUTS DOWN AFTER A FEW SECONDSSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PageSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PROBLEM 6 - GENERATOR DOESN’T PULL FULL LOADPROBLEM 7 - GENERATOR CIRCUIT BREAKER TRIPS / NO AC VOLTAGE PageSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PROBLEM 8 - ENGINE SHUTS DOWN UNDER LOADPROBLEM 9 - GENERATOR LOSES AC POWER THEN SHUTS DOWN Page12-WIRE PROBLEM 10 - NO AC OUTPUTSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PagePage PROBLEM 10 - NO AC OUTPUT CONTINUEDSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING Figure 2. Primer Switch TEST 3- CHECK POWER TO FUEL PUMPTEST 2- CHECK POWER TO PRIMER SWITCH TEST 1- CHECK 7.5 AMP FUSETEST 8- CHECK POWER SUPPLY TO STARTER MOTOR TEST 6- TEST PRIMER SWITCHTEST 7- CHECK WIRE 14A TO FUEL PUMP TEST 4- CHECK BATTERY/BATTERY CIRCUITFigure 5. Starter Contactor TEST 9- CHECK WIRE 56 POWER TO STARTER CONTACTORTEST 10- CHECK A6060 CIRCUIT BOARD POWER SUPPLY Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTINGTEST 11- TEST STARTER CONTACTOR TEST 12- TEST START-STOP SWITCHFigure 7. Start-Stop Switch TEST 13- CHECK FUEL SUPPLYFigure 9. Ignition Module & 4-Tab Connector TEST 21 - CHECK A6060 CIRCUIT BOARD OUTPUT TO WIRETEST 17- CHECK IGNITION POWER SUPPLY TEST 18- CHECK IGNITION SENSORTEST 24- CHECK ENGINE TEST 23- CHECK CARBURETIONTEST 22-TEST AUTOMATIC CHOKE Figure 10. Receptacle J2Note Cap the DC Link wires with a wire nut for safety TEST 27- TEST OIL TEMPERATURE SWITCHTEST 26- TEST OIL PRESSURE SWITCH TEST 28 - DC LINK VOLTAGE TESTNote Fluke 87 true RMS meter used in test TEST 30 - 12 POSITION HARNESS SIGNALS TESTTEST 29 - 12 POSITION HARNESS CONTINUITY TEST Figure 10 Free End of 12 Position HarnessPin 4 Wire #14 STATOR TESTS TEST 32 - POWER SUPPLY WINDING TESTFigure 11. 12 Position Connector on Inverter TEST 31 - STATIC TESTS ON INVERTERTEST 35 - BRIDGE RECTIFIER TEST TEST 36 - AC POWER WINDING TEST AC1/AC2/SL1/SL2TEST 34 -STATOR RESISTANCE VALUES Section ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTINGSection ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING PageElectrical Schematic PART SPECIFICATIONS AND CHARTSGeneral Specifications Wiring DiagramPage NOMINAL RESISTANCES OF GENERATOR WINDINGS ENGINE SPEEDS AND VOLTAGE SPECIFICATIONSPart LOAD %1 OF Part SPECIFICATIONS & CHARTSELECTRICAL SCHEMATIC DRAWING NO. 0D4947-B Page2 OF WIRING DIAGRAM DRAWING NO. 0D4947-BPart SPECIFICATIONS & CHARTS PageGV-220 GENERAL SPECIFICATIONSMODEL Part SPECIFICATIONS & CHARTSCRANKCASE COVER ASSEMBLY SPECIFICATIONS & CHARTSCRANKCASE ASSEMBLY Later model small frame GN engines have no crankshaft sleeve bearingPISTON CONNECTING ROD ASSEMBLYCRANKSHAFT Part SPECIFICATIONS & CHARTSMODEL PISTON CONTINUEDPart SPECIFICATIONS & CHARTS NOTE 2 Measure pump tip clearance on shaft in crankcase cover CAMSHAFT ASSEMBLYOIL PUMP Part SPECIFICATIONS & CHARTSMODEL SPECIFICATIONS & CHARTSPart MODELPage MAJOR FEATURES AND DIMENSIONS GENERATORPart SPECIFICATIONS & CHARTS Page MAJOR FEATURES AND DIMENSIONS INVERTERPart SPECIFICATIONS & CHARTS