Protect the RV electronics: If voltage or frequency is unstable, shut the generator down and avoid running sensitive loads until the cause is corrected.

When does it surge?

If it surges with no load, think fuel quality, carburetor restriction, vacuum/air leak, dirty air filter or governor trouble. If it surges only when the air conditioner starts, look at load size, fuel delivery and whether that appliance is drawing abnormal startup current.

Start with the easy checks

  • Turn off large loads and listen unloaded.
  • Check air filter condition and intake obstruction.
  • Confirm fuel level and age.
  • Check oil level and any stored fault code.
  • Make sure enclosure panels are installed as designed.

Fuel and carburetor clues

Old gasoline and partially blocked jets often create hunting. The generator may sound like it is revving up and down as the governor tries to maintain speed. If the unit sat unused, read Onan generator carburetor problems.

Governor and electrical-output limits

Do not bend linkages or adjust governor settings by ear. Generator speed affects output frequency on many non-inverter sets. A wrong adjustment can make power worse and damage equipment.

Related pages

Sources and review notes

Governor, carburetor and output checks should follow the exact generator service information. Cummins official manuals are listed through its RV generator manuals page.