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Cummins/Onan QG 4000 Generator Set

The Cummins/Onan QG 4000 is a 4000 kW (4 kVA) gasoline standby generator set. It is available at 120 V, Single-phase, 60 Hz and rated 33.3 A. The set measures 762×500.38×365.76 mm (30.0×19.7×14.4 in), weighs about 79.83 kg (176 lb) and produces 66.5 dBA at 3 m.

4000 kW
Standby
5
Document types

How to read your Cummins/Onan serial & model number →

Specifications

Fuelgasoline
Frequency60.0 Hz
Standby power4000 kW
Prime power4 kW
Voltage options120 V
Phase1
Rated current33.3 A
Power factor1
Battery voltage12 V
Battery quantity1
Max ambient500 °C
Dimensions (L×W×H)762×500×365 mm
Dry weight79 kg
Sound level66.0 dBA @ 3 m

Maintenance & consumables

ItemSpecCapacityPart #Interval
Air filterCheck for blocked air flow or other possible causes of overheating.— find
Fuel filter— find
Oil filterReplace air filter.— find
Belt— find
Coolant—
Oil—

Common questions

What is the power rating of the Cummins/Onan QG 4000?

The Cummins/Onan QG 4000 is rated 4000 kW standby.

What fuel does the Cummins/Onan QG 4000 use?

The Cummins/Onan QG 4000 runs on gasoline.

Troubleshooting

15

Symptoms & remedies

SymptomCauseRemedy
Crank but won’t start1. Fuel below generator pickup level in tank. 2. Fuel supply shutoff valve closed. 3. Carbon deposits on spark plug(s). 4. Low oil level.
Exhausting black smoke1. Dirty air filter. 2. Choke stuck or misadjusted.
Unit runs then stops, or stops when driving around a corner1. Low fuel level. 2. Low oil level. 3. Excess oil.
Unit starts and runs, then stops when the start switch is released1. Low fluid levels. 2. Possible overheating. 3. Other functional problem.
Unit runs then surges1. Loose or worn spark plug leads. 2. Defective ignition coil, wiring, or control components. 3. Faulty spark plug. 4. Governor out of adjustment. 5. Combustion air pre-heat malfunction. 6. Carburetor icing. 7. Carburetor varnishing.
Circuit breaker trips1. Overloaded circuit.
No electric output1. Tripped circuit breaker. 2. Other function problem.
Fails To CrankLow battery.Check battery fluid level and charge or replace the battery if necessary.
Cranks slowlyLow battery.Check battery voltage at generator. Bad battery connection. Clean and tighten all battery cable connections. Incorrect oil viscosity. Replace with recommended viscosity oil.
Cranks but won’t startFuel below generator pickup level in tank.Add fuel. Carbon deposits on spark plug(s). Remove spark plug(s) and replace. Low oil level. Add oil.
Air conditioner thermal overloadDue to thermal overloadThe air conditioner thermal overload will reset itself after the compressor cools. Some, but not all RV air conditioner thermostats have built-in time delays to prevent short-cycling.
Short-cycling of air conditionerWhen the thermostat is mounted so that cold air blows directly on itDirect the flow of air from the air conditioner away from the thermostat or relocate the thermostat. You can prevent air conditioner short-cycling by always ensuring the air conditioner rests for 3–4 minutes after the compressor shuts off before trying to restart it.
Generator overloadShut down the generator due to overload; or trip the circuit breakers on the generator or the main electrical panel will stop the flow of power. Turn off all appliances before resetting the breaker. If the breaker trips again with all electrical loads off, you may have a short circuit in your wiring.
Generator surgingChanges in generator engine speed (called surging) can damage appliances in your RV; caused by inadequate fuel supply, lack of exercise and poor maintenance.Ensure adequate generator fuel supply. Follow the generator exercise recommendations or the out-of-service protection recommendations outlined in your operator’s manual. Contact your local Cummins authorized RV service and parts dealer to diagnose fuel supply problems.
Unit Runs Then Surges — Only applicable on older modelsLoose or worn spark plug leads, Defective ignition coil, wiring, or control components, Faulty spark plug, Governor out of adjustment, Combustion air pre-heat malfunction, Carburetor icing, Carburetor varnishingCheck spark plug leads at spark plug & ignition coil., Contact a Cummins Onan Authorized RV Service & Parts Dealer., Remove spark plug & clean or replace., Contact a Cummins Onan Authorized RV Service & Parts Dealer., Contact a Cummins Onan Authorized RV Service & Parts Dealer., Move carburetor pre-heater to the winter position., Try fuel system cleaner and contact dealer if no change.

Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.

Parts

78model family
Part #DescriptionQtySystem
122-0645Cquartsc3.5Oil filter Amazon eBay PartsGeek
122-0800Filter, Oil Without Hex Nut1Oil filter PartsGeek FridayParts $39.99
122-0800Cquartsc3.5Oil filter Amazon eBay PartsGeek
122-0836CAir FilterAir filter Amazon eBay PartsGeek
140-2105COil FilterOil filter Amazon eBay PartsGeek
140-2379C140-2379cAir filter Amazon eBay PartsGeek
140-2379F140-2379cAir filter Amazon eBay PartsGeek
140-2680IAir FilterAir filter Amazon eBay PartsGeek
140-2897IOil FilterOil filter Amazon eBay PartsGeek
140-3071IAir FilterAir filter Amazon eBay PartsGeek
140-3116COil FilterOil filter Amazon eBay PartsGeek
140-3280COil FilterOil filter Amazon eBay PartsGeek
140-3280EOil FilterOil filter Amazon eBay PartsGeek
140-4151IOil Filter.11 quartsOil filter Amazon eBay PartsGeek
147-0860ISpark PlugSpark plug Amazon eBay PartsGeek
149-1353GAir FilterAir filter Amazon eBay PartsGeek
149-2137HAir FilterAir filter Amazon eBay PartsGeek
149-2279F149-2279FFuel filter Amazon eBay PartsGeek
149-2333ISpark PlugSpark plug Amazon eBay PartsGeek
149-2341Filter, Fuel1Fuel filter PartsGeek
149-2457HAir FilterAir filter Amazon eBay PartsGeek
149-2457IAir FilterAir filter Amazon eBay PartsGeek
149-2513IAir FilterAir filter Amazon eBay PartsGeek
149-2661IAir FilterAir filter Amazon eBay PartsGeek
149-2834IAir FilterAir filter Amazon eBay PartsGeek
167-0241DSpark PlugSpark plug Amazon eBay PartsGeek
167-026302H2Spark plug PartsGeek
167-0272BSpark PlugSpark plug Amazon eBay PartsGeek
167-0272CSpark PlugSpark plug Amazon eBay PartsGeek
167-0275HSpark PlugSpark plug Amazon eBay PartsGeek
167-0305HSpark PlugSpark plug Amazon eBay PartsGeek
167-1638HSpark PlugSpark plug Amazon eBay PartsGeek
167-1652ISpark PlugSpark plug Amazon eBay PartsGeek
185-2289Glow Plug (12 Volt)Glow plug Amazon eBay $40.00 PartsGeek
185-5421Plug, Glow4Glow plug Amazon eBay PartsGeek
185-5990Glow Plug (12 Volt)1Glow plug Amazon eBay PartsGeek
185-6623Plug, Glow4Glow plug Amazon eBay $45.00 PartsGeek
187-1289Plug, Glow (HR1)3Glow plug Amazon eBay PartsGeek
122-0645B122-0645BService part / kit Amazon eBay PartsGeek
122-0645D122-0645DService part / kit Amazon eBay PartsGeek
122-0645I122-0645IService part / kit Amazon eBay PartsGeek
122-0800B122-0800BService part / kit Amazon eBay PartsGeek
122-0827B122-0827BService part / kit Amazon eBay PartsGeek
122-0833C122-0833CService part / kit Amazon eBay PartsGeek
122-0893E122-0893EService part / kit Amazon eBay PartsGeek
140-0495D140-0495DService part / kit Amazon eBay PartsGeek
140-1229D140-1229DService part / kit Amazon eBay PartsGeek
140-2609E140-2609EService part / kit Amazon eBay PartsGeek
140-2842I140-2842IService part / kit Amazon eBay PartsGeek
148-0898C148-0898CService part / kit Amazon eBay PartsGeek
148-0898I148-0898IService part / kit Amazon eBay PartsGeek
149-1353I149-1353IService part / kit Amazon eBay PartsGeek
149-191405EService part / kit PartsGeek
149-2137I149-2137IService part / kit Amazon eBay PartsGeek
149-2279I149-2279IService part / kit Amazon eBay PartsGeek
167-0237B167-0237BService part / kit Amazon eBay PartsGeek
167-0237C167-0237CService part / kit Amazon eBay PartsGeek
167-0237D167-0237DService part / kit Amazon eBay PartsGeek
167-0247D167-0247DService part / kit Amazon eBay PartsGeek
167-0262B167-0262BService part / kit Amazon eBay PartsGeek
167-0262D167-0262DService part / kit Amazon eBay PartsGeek
167-0272D167-0272DService part / kit Amazon eBay PartsGeek
167-0272G167-0272GService part / kit Amazon eBay PartsGeek
167-0272I167-0272IService part / kit Amazon eBay PartsGeek
167-0275I167-0275IService part / kit Amazon eBay PartsGeek
167-0298B167-0298BService part / kit Amazon eBay PartsGeek
167-0298C167-0298CService part / kit Amazon eBay PartsGeek
167-0305I167-0305IService part / kit Amazon eBay PartsGeek
185-5835B185-5835BService part / kit Amazon eBay PartsGeek
185-5835C185-5835CService part / kit Amazon eBay PartsGeek
187-1000E187-1000EService part / kit Amazon eBay PartsGeek
202-3005Service part / kit PartsGeek
286-6467)Service part / kit PartsGeek
326-5366)Service part / kit PartsGeek
333-0802Service part / kit Amazon eBay $20.00 PartsGeek
525-0305Quart Can (Onan Green Enamel)1Service part / kit PartsGeek
EC-20Battery and Generator Monitoring System1Service part / kit PartsGeek
EC-30WWireless Autostart System1Service part / kit PartsGeek

Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.

Fuel consumption

RatingLoadL/hgal/h
Half load
Prime
Standby
Standby50%2.270.6
Standby100%3.410.9

Available documents

Spec sheet — 0043135 (Cummins/Onan)Reference — 0059498 (Cummins/Onan)Reference — F-1823-ENOwner's manual — 0056746 (Cummins/Onan)Parts manual — 0058349 (Cummins/Onan)Parts manual — 0058449 (Cummins/Onan)Service manual — Cummins-Onan-RV-Generator-Handbook (Cummins/Onan)Service manual — F-1123-EN (Cummins/Onan)