By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received from a reader while he was serving as RVtravel.com’s technical editor.
I’m having a dilemma with my Onan generator. It won’t stay running and it quits when I take my finger off the START button, or cuts out and dies if it decides to run at all. It has been professionally tuned, has a new control panel, fuel pump is fine, etc., etc. No one can figure out the problem. HELP! It’s limiting the use of our RV. —Deb
It looks as though you’ve had this thing looked at professionally, but there are a couple of possibilities that are easy. First, how much fuel do you have in the coach? The generator uses a separate pick-up tube in the fuel tank which is higher than the engine tube. So, once your tank gets down to about 1/4, the genset will stop working so as not to use up all the fuel and stranding the coach. Second, make sure the oil is full. Onan gensets have a low oil cut-off that can affect the unit’s operation.
The newer Onan gensets will flash a code on the start switch light if they encounter a problem. If you go to www.cumminsonan.com they have a manual section which should give you additional troubleshooting options and a guide to deciphering the codes.
There are additional causes of these symptoms, which require specific testing of the system. I would recommend seeking out a Cummins Onan service center to have it looked at.