Quick answer

Disconnect every load and restart only through the exact manual procedure. Record whether the engine is stable at no load, then compare one known-good compatible low load. Verify generator continuous and starting ratings for the selected fuel, receptacle and breaker limits, cord condition, load nameplate, and starting demand. Check only accessible fuel, vent, air-filter, oil, and control items. If it bogs with a small verified load, produces abnormal voltage or frequency, smokes, backfires, leaks, or trips protection, keep it out of service.

Symptom boundary worksheet

Separate a load event from an engine-power limitation

Choose the closest observation after the generator is in its approved location and every load has been removed. The worksheet keeps the next check outside guarded engine, fuel, alternator, transfer and panel work.

Needs verification

Keep that load disconnected

Starting kVA, wrong voltage, a locked motor, or a damaged connection can create the event.

  1. Record running and starting data.
  2. Inspect the cord while de-energized.
  3. Use manufacturer motor-start review.

Never troubleshoot a combustion generator indoors. Do not bypass a breaker, GFCI, low-oil, carbon-monoxide or controller shutdown, and do not open energized generator or transfer equipment.

First splitNo-load stable or unstable
Load checkRunning plus starting demand
External engine checksFuel, vent, air and oil
Repeated symptomService boundary
DECISION PATHUse the evidence in the right order01STEP 1Record what changes atthe exact load event02STEP 2Separate continuousoverload from a shortstarting03STEP 3Complete only themanufacturer-authorizedexternal04STEP 4Verify the source andload before return toservice
Follow the decision in order; a later check cannot repair a failed earlier check.

Record what changes at the exact load event

Note the generator warm-up time, economy mode, selected fuel, output indicators, sound, exhaust, voltage or frequency display, and connected equipment. Record whether the symptom occurs immediately at plug-in, only when a motor starts, after several minutes, or only after the generator becomes hot.

Remove all loads before another start. If the engine is unstable with no load, move to the no-load troubleshooting path. If it is stable until one device connects, keep that device and cord disconnected until their voltage, current, starting demand, and condition are verified.

Separate continuous overload from a short starting event

Add simultaneous running watts and the largest additional motor-start demand. Compare both with the generator ratings for the selected fuel and operating condition. A compressor, pump, welder, or transformer can create a short kVA demand that is much larger than its running watts.

A short circuit, locked motor, wrong voltage, damaged cord, or failing appliance can also cause the generator to labor. Do not repeatedly connect the same suspect load and do not install a larger breaker. Use one known-good low-load test only if the manual permits.

Bogging symptom distinctions
ObservationReview firstStop condition
Only one motor startStarting amps, voltage and cordRepeated stall or trip
All loads togetherSimultaneous running totalContinuous overload indication
Small verified loadFuel, air, engine and alternator serviceAbnormal output or exhaust
After warmingFuel vent, cooling and temperature historyHeat, leakage or recurring shutdown
BEFORE YOU ACTKeep four checkpoints visibleREADNo-load stable orunstableDo not infer missing data.CALCULATERunning plusstarting demandDo not infer missing data.VERIFYFuel, vent, air andoilDo not infer missing data.CONFIRM4 primary referencesOpen and verify the source.
Keep equipment labels, calculations, system limits, and primary references separate.

Complete only the manufacturer-authorized external engine checks

Confirm fresh correct fuel, fully open fuel valve, correct dual-fuel selector, propane regulator and cylinder state where applicable, natural-gas pressure documentation, tank vent position, clean air-filter element, unobstructed cooling, correct oil level, and no visible leaks or damaged hoses.

Do not adjust governor speed, carburetor jets, regulator pressure, valve clearance, ignition timing, or alternator controls from a generic article. These changes can create unsafe frequency, voltage, mixture, emissions, or engine speed.

Verify the source and load before return to service

Qualified service may need to test fuel flow or pressure, compression, governor response, engine speed, voltage, frequency, winding condition, inverter or AVR operation, and the suspected load. Preserve the original symptom and do not clear controller history repeatedly.

After correction, warm up at no load and add verified loads in the approved sequence. Monitor output, overload indicators, engine recovery, cords, connectors, and equipment alarms. Stop immediately if the speed or output becomes unstable again.

Frequently asked questions

Common questions

Why does my generator run fine until I plug something in?

The connected load may be too large, have high starting demand, be damaged, use the wrong voltage, or reveal an engine fuel, air, governor, or generator-output problem.

Can stale fuel make a generator bog under load?

Yes. Stale fuel and restrictions can limit the fuel available at higher engine demand, but overload and equipment faults can create similar symptoms.

Why does the generator bog when a compressor starts?

Compressor starting current can greatly exceed running current. Use the exact starting data and generator motor-start capability, not only running watts.

Should I adjust the governor?

Do not make a generic governor adjustment. Incorrect speed can produce unsafe frequency and voltage. Use model-specific qualified service.

Primary references

CordFind summarizes connector specifications and public safety guidance. Always follow the instructions supplied with your equipment.

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