1987 Onan Generator Repair Manual Download

The 1987 Onan Generator Repair Manual provides comprehensive technical documentation for servicing and maintaining Onan generators from the 1987 model year. This manual covers troubleshooting procedures, repair instructions, parts identification, electrical schematics, and maintenance schedules for various Onan generator models including the Emerald, Marquis, and Commercial series. Below are key sections for safety procedures, technical specifications, repair procedures, parts diagrams, and troubleshooting guides.

1. Safety Precautions 2. Model Identification 3. Technical Specifications 4. Maintenance Procedures 5. Engine Repair 6. Electrical System 7. Fuel System 8. Parts Diagrams 9. Troubleshooting 10. Wiring Schematics

Safety Precautions

Critical safety procedures for working on 1987 Onan generators.

HazardSafety Procedure
Electrical ShockDisconnect battery and generator output before servicing
Fuel FireWork in well-ventilated area; no smoking or open flames
Moving PartsEnsure generator is completely stopped before inspection
Hot SurfacesAllow engine to cool before performing maintenance
Battery AcidWear protective gloves and eyewear when handling batteries

Model Identification

Identifying your specific 1987 Onan generator model for proper repair procedures.

  1. Locate model number plate on generator housing
  2. Record serial number and spec code
  3. Identify engine type (OHV, cast iron, aluminum)
  4. Determine generator output (kW rating)
  5. Note voltage configuration (120/240V single phase, etc.)

WARNING! Using incorrect repair procedures for your specific model can cause equipment damage and void warranties.

Technical Specifications

Detailed specifications for 1987 Onan generator models.

Maintenance Procedures

Scheduled maintenance procedures for optimal generator performance.

Daily: Visual inspection for leaks, check oil level, verify coolant level

Monthly: Test run under load, check battery charge, inspect air filter

Annual: Change oil and filter, replace spark plugs, clean fuel system, test voltage output

Maintenance: Oil change intervals (100 hours/annually), air filter inspection (50 hours), spark plug replacement (500 hours), valve adjustment (1000 hours).

Engine Repair

Step-by-step engine repair procedures for 1987 Onan generators.

  1. Cylinder Head Removal: Drain coolant, remove rocker cover, extract head bolts
  2. Piston Replacement: Remove oil pan, disconnect connecting rods, extract pistons
  3. Valve Adjustment: Set clearance to 0.006-0.008 inches (cold)
  4. Carburetor Rebuild: Disassemble, clean jets, replace gaskets, reassemble
  5. Governor Adjustment: Set RPM to 1800 for 60Hz output

Tip: Always use genuine Onan replacement parts for optimal performance.

Electrical System

Electrical system diagnosis and repair for 1987 Onan generators.

  1. Test stator windings for continuity and ground faults
  2. Check rotor slip rings for wear and carbon buildup
  3. Verify voltage regulator output (12-14VDC for excitation)
  4. Test circuit breakers and overload protection
  5. Inspect wiring harness for chafing and corrosion

WARNING! High voltage present even when engine is not running. Always discharge capacitors before servicing.

Fuel System

Fuel system maintenance and repair procedures.

Carburetor: Float level adjustment, main jet cleaning, choke mechanism service

Fuel Pump: Pressure testing (2.5-4.5 PSI), diaphragm replacement

Fuel Filter: Replace annually or every 200 hours

LP/NG Systems: Regulator adjustment, gas valve servicing, leak testing

Parts Diagrams

Exploded view diagrams with part numbers for 1987 Onan generators.

AssemblyDiagram ReferenceCommon Replacement Parts
EngineFig. 1-5Pistons, rings, bearings, gaskets
Fuel SystemFig. 6-8Carburetor kits, fuel pumps, filters
ElectricalFig. 9-12Voltage regulators, rotors, stators
Control PanelFig. 13-15Switches, meters, circuit breakers

Troubleshooting

Common problems and solutions for 1987 Onan generators.

SymptomPossible CauseCorrective Action
Engine cranks but won't startFuel delivery, spark, compressionCheck fuel flow, test spark plugs, verify compression
No output voltageExcitation failure, rotor issuesFlash field, test rotor resistance, check brushes
Engine runs roughCarburetion, ignition timingClean carburetor, adjust timing, check valves
OverheatingCooling system, overloadingClean cooling fins, check thermostat, reduce load
Battery not chargingAlternator, regulator, wiringTest alternator output, check regulator, inspect wiring

Reset: Manual reset circuit breakers on control panel.

Service Support: Contact Onan technical support for factory assistance.

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