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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 13581
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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Our RV Generator is a Cummins Onan 5500. We started it and

Customer Question

Our RV Generator is a Cummins Onan 5500. We started it and it ran fine for a few minutes then cut off. It has about 170 hours on it. We've cleaned the spark arrestor at about 70 hours and changed the oil. When it cut off it flashed the 3 then 6 times indicating what we think is a fault code 36? Which says check fuel which is full, or clean spark arrestor, clean air filter, or spark plugs...... any idea what could have made it just randomly cut off? Could it possibly be the oil level which I know will cause it not to run, but that wasn't listed on that fault code 36 in the manual. We are trying to find the spark plug numbers for it to buy new plugs as it has two, but we can't seem to find the correct number or crossover number.
Submitted: 1 year ago.
Category: Small Engine
Expert:  Charles replied 1 year ago.


Thanks for your question!!

The onan Generators have very sensitive Carbs. The problem is most likely the Carburetor. How old is the Carb? and how often do you run the Generator?

Expert:  Charles replied 1 year ago.

Its recomended that the Generator be ran under load every 3-4 weeks for an hour at minimum. Under load meaning, run the a/c and such to "make the generator work.

This keeps fuel from getting stale in the carb and creating junk in the jets of the carb.

In most cases if it is the carb your better off replacing it. Rebuild kits are a 50/50 shot.

Expert:  Charles replied 1 year ago.

One way to tell if its the spark plugs or not is to remove the breather and shoot just a very tiny bit carb cleaner into the carb. If it starts up and shuts down again, its not the plugs.

I will be on and off the computer, if I miss you just replay back and I will be notified, I will respond back to you as soon as I can.