How to Troubleshoot an Onan RV Generator

The Onan RV generator provides electrical power to the RV's central air conditioning unit and heavy-load appliances. Traveling in an RV with a faulty generator can be uncomfortable and dangerous in extreme temperatures. Common problems with the Onan RV generator include electrical system failures, fuel and oil issues, faulty spark plugs and air flow blockages. Troubleshoot Onan RV generator problems by testing, step-by-step, each possible cause.

Things You'll Need

• Crescent wrench
• Multimeter

Instructions

1. Check the condition of the electrical system including battery and fuses. Check the battery for correct electrolyte levels. Tighten the battery cables. Test for faulty or failed fuses with a mulitmeter. Replace fuses as needed. Switch off all appliances to minimize the load on the generator. Reset the circuit breaker.

2. Check the fluid levels including fuel and oil. Confirm the fuel tank is at least half full in order to power the generator. Add fuel as needed. Open the fuel supply valve fully. Check the oil reservoir for proper oil level and viscosity. Add or drain oil to the correct level. If necessary, replace the oil with one that has the correct viscosity.

3. Examine the spark plugs for excess carbon deposits. Clean the sparks plugs with a dry towel. Replace the spark plugs if necessary.

4. Check the condition of the air filter. Clean or replace the air filter if necessary. Examine the area around the air filter for possible air flow blockage.

5. Contact a qualified Cummins Onan service center if the problem persists.

Tips & Warnings

• Run the Onan RV generator with a heavy electrical load once per month for two hours for routine maintenance and to prevent moisture accumulation and fuel system damage.

• Do not crank the Onan RV generator for more than ten seconds. Wait thirty seconds if the generator does not start.

References

• Cummins Onan: RV Generators FAQ
• Cummins Southern Plains: Onan RV Generator Operating Tips

Resources

• Cummins Onan: Recreational Vehicle Generator Set Specification Sheets and Service Diagrams