Service parts for the GH400
Grouped by system, with how many of each the parts manual calls for.
Air intake
1 requiredFuel system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
Ratings spec sheet not in our library yet — see the documents below.
Maintenance & consumables
| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | foam wrapper on paper element air filter | Fs-1830-2 | Amazon eBay | ||
| Fuel filter | sediment bowl for fuel filter | Y-1846 | Amazon eBay | ||
| Oil filter | not explicitly stated in the document | — | |||
| Spark plug | remove and inspect at intervals indicated in the Operator's Manual, clean electrode with wire brush, measure and reset electrode gap to specified setting, replace if electrode or insulator are deformed or cracked | — |
Common questions
Which fuel filter part number does the Cummins/Onan GH400 take?
The Cummins/Onan GH400 uses fuel filter part number Y-1846.
What air filter fits the Cummins/Onan GH400?
The Cummins/Onan GH400 uses air filter part number Fs-1830-2.
Troubleshooting
106Symptoms & remedies
| Symptom | Cause | Remedy |
|---|---|---|
| Engine Misfires | Faulty ignition due to: worn or fouled spark plug | Clean or replace spark plug. |
| Engine Misfires | Faulty ignition due to: faulty ignition system | See Ignition System section. |
| Engine Misfires | Faulty ignition due to: faulty plug wire | Check spark plug wire and replace if necessary. |
| Engine Misfires | Lean fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Engine Misfires | Lean fuel mixture due to: incorrect float level | Check carburetor float. |
| Engine Misfires | Lean fuel mixture due to: dirt in carburetor | Disassemble carburetor and clean all passages. |
| Engine Misfires | Lean fuel mixture due to: vacuum leak | Locate leak, check for loose carburetor. |
| Engine Misfires | Contaminated fuel | Drain fuel tank and refill with fresh fuel. |
| Engine Misfires | Dirty air cleaner | Clean or replace air cleaner. |
| Engine Backfires | Faulty ignition due to: worn or fouled spark plug | Clean or replace spark plug. |
| Engine Backfires | Faulty ignition due to: faulty ignition system | See Ignition System section. |
| Engine Backfires | Lean fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Engine Backfires | Lean fuel mixture due to: incorrect float level | Check carburetor float. |
| Engine Backfires | Lean fuel mixture due to: dirt in carburetor | Disassemble carburetor and clean all internal passages. |
| Engine Backfires | Lean fuel mixture due to: vacuum leak | Locate leak, check for loose carburetor. |
| Engine Backfires | Excessive engine wear | See Engine Block Assembly section. |
| Engine Lacks Power | Faulty ignition due to: worn or fouled spark plug | Clean or replace spark plug. |
| Engine Lacks Power | Faulty ignition due to: faulty ignition system | See Ignition System section. |
| Engine Lacks Power | Dirty air cleaner | Clean or replace air cleaner. |
| Engine Lacks Power | Restricted fuel flow due to plugged fuel filter | Clean or replace fuel filter. |
| Engine Lacks Power | Incorrect fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Engine Lacks Power | Incorrect fuel mixture due to: incorrect float level | Check carburetor float. |
| Engine Lacks Power | Incorrect fuel mixture due to: dirt in carburetor | Disassemble carburetor and clean all internal passages. |
| Engine Lacks Power | Exhaust system blocked or restricted | Locate and remove cause of blockage. |
| Engine Lacks Power | Incorrect valve clearance or defective valve(s) | Adjust valve clearance/inspect valves (see Engine Block Assembly section). |
| Engine Lacks Power | No load speed set too low | Adjust governor setting. |
| Engine Lacks Power | Excessive engine wear or damage to engine | See Engine Block Assembly section. |
| Engine Lacks Power | Choke valve blockage or choke lever set incorrectly | Open choke lever fully, if problem continues see Fuel System section. |
| Engine Overheats | Restricted air flow due to dirt or debris blocking air inlet or outlet | Clear away any debris that may restrict airflow. |
| Engine Overheats | Dirt or oil covering engine cooling fins | Clean away all dirt and oil from engine cooling fins. |
| Engine Overheats | Cooling fan plugged or broken | Inspect cooling fan, see Generator Service section. |
| Engine Overheats | Lean fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Engine Overheats | Lean fuel mixture due to: incorrect float level | Check carburetor float. |
| Engine Overheats | Lean fuel mixture due to: dirt in carburetor | Disassemble carburetor and clean all internal passages. |
| Black Exhaust Smoke | Rich fuel mixture due to: dirty air cleaner | Clean or replace air cleaner. |
| Black Exhaust Smoke | Rich fuel mixture due to: choke closed | Check choke setting. |
| Black Exhaust Smoke | Rich fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Black Exhaust Smoke | Rich fuel mixture due to: dirt in the carburetor | Disassemble carburetor and clean all internal passages. |
| White or Blue Exhaust Smoke | Lean fuel mixture due to: dirty air cleaner | Clean or replace air cleaner. |
| White or Blue Exhaust Smoke | Lean fuel mixture due to: incorrect float level | Check carburetor float. |
| White or Blue Exhaust Smoke | Lean fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| White or Blue Exhaust Smoke | Lean fuel mixture due to: dirt in the carburetor | Disassemble carburetor and clean all internal passages. |
| White or Blue Exhaust Smoke | Clogged or faulty breather | Clean or replace breather. |
| White or Blue Exhaust Smoke | Contaminated fuel | Drain and replace fuel. |
| White or Blue Exhaust Smoke | Excessive engine wear | See Engine Block Assembly section. |
| Engine Hunts or Surges | Sticking or binding governor linkage | Check linkage alignment and straighten or replace. Clean governor linkage. |
| Engine Hunts or Surges | Incorrect governor adjustment | See Governor section. |
| Engine Hunts or Surges | Faulty governor spring | Replace governor spring. |
| Engine Hunts or Surges | Incorrect fuel mixture due to: incorrectly adjusted carburetor | See Carburetor Adjustment section. |
| Engine Hunts or Surges | Incorrect fuel mixture due to: incorrect float level | Check carburetor float. |
| Engine Hunts or Surges | Incorrect fuel mixture due to: dirt in carburetor | Disassemble carburetor and clean all internal passages. |
| Engine Hunts or Surges | Governor mechanism worn excessively | See Engine Block Assembly section. |
| Engine Hunts or Surges | Fuel supply problem caused by: Dirty fuel filter | Clean or replace fuel filter. |
| Engine Hunts or Surges | Fuel supply problem caused by: Contaminated fuel supply | Drain and refill fuel supply. |
| High Oil Consumption | Oil viscosity is too light or oil is diluted | Drain oil and refill with correct viscosity oil. |
| High Oil Consumption | Crankcase breather valve is dirty or defective | Clean crankcase breather or replace if defective. |
| High Oil Consumption | Oil leaks | Locate source of leak and repair as required. |
| High Oil Consumption | Excessive engine wear | See Engine Block Assembly section. |
| High Oil Consumption | Light loading | Do not run set at no load for long periods of time. |
| Engine Shuts Down and Will Not Restart | Low oil level | Add oil as required. |
| Engine Shuts Down and Will Not Restart | Low oil level switch defective | Replace oil level switch (see Engine Block Assembly section). |
| Engine Shuts Down and Will Not Restart | Fouled spark plug | Clean or replace spark plug. |
| Engine Shuts Down and Will Not Restart | Faulty fuel system | Refer to Fuel System section for service procedures. |
| Engine Does Not Crank (Electric Start Models Only) | Defective Start/On/Stop switch | Check switch for continuity and replace if defective. |
| Engine Does Not Crank (Electric Start Models Only) | Open circuit in wiring between Start/On/Stop switch and starter solenoid or between battery and starter | Check wiring and connections for continuity and repair if defective. |
| Engine Does Not Crank (Electric Start Models Only) | Insufficient voltage for cranking due to: Battery not charged | Check condition of battery and recharge or replace as needed. |
| Engine Does Not Crank (Electric Start Models Only) | Insufficient voltage for cranking due to: terminal connections loose or dirty | Clean and tighten battery cable connections, starter connections and ground connections. |
| Engine Does Not Crank (Electric Start Models Only) | Insufficient voltage for cranking due to: defective charge circuit | Check diode and replace if defective. |
| Engine Does Not Crank (Electric Start Models Only) | Insufficient voltage for cranking due to: defective Ignition Control Unit charge circuit | Refer to Section 6, Engine - Primary Systems for test procedures. |
| Engine Does Not Crank (Electric Start Models Only) | Defective starter solenoid or starter | Refer to Section 6, Engine - Primary Systems for test procedures. |
| Engine Does Not Start (Recoil Start Models Only) | Defective On/Stop or Engine On/Off switch | Check switch for continuity and replace if defective. |
| Engine Does Not Start (Recoil Start Models Only) | Open circuit in wiring between On/Stop or Engine On/Off switch | Check wiring and connections for continuity and repair if defective. |
| Engine Does Not Start (Recoil Start Models Only) | Defective Ignition Module | Refer to Section 6, Engine - Primary Systems for test procedures. |
| Engine Does Not Start (Recoil Start Models Only) | Low oil level | Check oil level and fill if necessary. |
| Full Power Switch Does Not Function Properly (Only used on certain models) | Defective Full Power switch | Check switch for continuity and replace if defective. |
| Full Power Switch Does Not Function Properly (Only used on certain models) | Wire connections to Full Power switch are not making contact or are miswired | Check for good wire connections and compare connections with wiring diagram in Section 11. |
| Idlematic Does Not Operate (Only used on certain models) | Defective Idlematic switch | Check switch for continuity and replace if defective. |
| Idlematic Does Not Operate (Only used on certain models) | Wire connections to Idlematic switch, Idlematic Control, or Idlematic Solenoid are not making contact or are miswired | Check for good wire connections and compare connections with wiring diagram in Section 11. |
| Idlematic Does Not Operate (Only used on certain models) | Defective Idlematic Solenoid | Check Idlematic solenoid for a binding plunger movement. |
| Idlematic Does Not Operate (Only used on certain models) | Defective Idlematic Control | Check to see that the appropriate generator leads pass through the current transformer. Test Idlematic Control. |
| Engine Cannot Be Turned Off With Switch | Defective Start/On/Stop switch, On/Start switch, or Engine On/Off switch | Check switch for continuity and replace if defective. |
| Engine Cannot Be Turned Off With Switch | Open circuit in switch wiring | Check wire connections to switch. |
| No AC Output Voltage | Open AC circuit breaker | Locate cause of overload and correct as required. Reset breaker. |
| No AC Output Voltage | Open circuit between stator main coil and AC receptacle. Defective receptacle. | Check for continuity and correct if circuit is open. Check for defective receptacle. |
| No AC Output Voltage | Defective stator main coil. | Test stator main coil for open, shorted, or grounded windings and replace if defective. |
| AC output voltage only 3 to 18 VAC | Defective stator sub coil. | Test stator sub coil for open, shorted, or grounded windings and replace if defective. |
| AC output voltage only 3 to 18 VAC | Defective rotor coil or defective rotor winding diode. | Test rotor coil for open, shorted, or grounded winding and defective diode. Replace rotor if defective. |
| AC output voltage only 3 to 18 VAC | Open or shorted capacitor. | Test capacitor for open or short and replace if defective. |
| AC Output Voltage Too Low or Too High | Engine governor incorrectly adjusted | Refer to Engine Primary System section. |
| Noisy Generator | Worn rotor shaft bearing. | Replace end bearing. |
| Noisy Generator | Rotor and stator rubbing together due to: varnish lumps | Check for varnish lumps between rotor and stator and remove as required. |
| Noisy Generator | Rotor and stator rubbing together due to: rotor misaligned with crankshaft | Follow specified assembly procedures to correct rotor to crankshaft alignment |
| Generator Overheats | Generator overloaded due to defective circuit breaker | Replace circuit breaker. Do Not exceed specified load when operating set |
| Generator Overheats | Airflow restricted due to dirt or debris covering vent openings in cover or adapter. | Clean away all dirt or debris as required. |
| Generator Overheats | Stator windings covered with oil or dirt | Clean stator windings |
| Generator Overheats | Defective windings in rotor or stator. | Test each component for open, grounded, or shorted windings and replace if defective. |
| Low or No DC Output | Open DC circuit breaker. | Locate cause of overload and correct as required. Reset breaker. |
| Low or No DC Output | Open circuit between stator DC coil and diode assembly or between diode assembly and receptacle. | Check for continuity and correct if circuit is open. Check for defective receptacle. |
| Low or No DC Output | Defective stator DC coil. | Test stator DC coil for open, grounded or shorted windings. |
| Low or No DC Output | Defective diode assembly. | Test Diode Assembly for open or short |
| AC output voltage only 6 to 18 VAC | Defective rotor coil. | Test rotor coil for open, shorted, grounded windings and replace if defective. |
| AC output voltage only 6 to 18 VAC | Defective stator sub coil. | Test stator sub coil for open, shorted, or grounded winding and replace if defective. |
| AC output voltage only 6 to 18 VAC | Faulty brushes or slip rings. | Check brushes and replace if defective. Inspect slip rings and clean if needed. |
| AC output voltage only 6 to 18 VAC | Faulty Voltage Regulator (AVR). | If the rotor and stator test good, and the brush block and slip rings are good, replace the AVR module and recheck. |
| AC output voltage only 6 to 18 VAC | Faulty permanent magnet in rotor. | Replace rotor after checking other possible causes for 6 to 18 VAC. |
| AC Output Voltage Too Low or Too High | Faulty voltage regulator (AVR) | Replace the AVR module and recheck. |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Parts
4| Part # | Description | Qty | System | |
|---|---|---|---|---|
| Fs-1828-2 | paper element only air filter | Air filter | Amazon eBay | |
| Fs-1830-2 | foam wrapper on paper element air filter | Air filter | Amazon eBay | |
| Y-1846 | sediment bowl for fuel filter | Fuel filter | Amazon eBay | |
| CO31FO.58 | FLOAT CHAMBER | Service part / kit | buy |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
Service manual — 981-0510 Onan EGH EGS Service Manual (2-1994) (Cummins/Onan)
This page was generated from the 1 manufacturer document above by automated extraction; every figure shown is copied from one of them. How the data is compiled.