Community Forums

RV Trax · 07-07-2009, 06:09 PM

I have a problem with my 5.5 Onan Marquis generator of quitting intermitently while driving. It will run flawlessly while parked for many hours. Once I have traveled about 1 hour, it will stumble and quit. It will not restart for about a 1/2 hour, then the same problem persists. I have a friend with the same generator with the same problem. He has a GM Work horse chassis and I have a Ford V-10. The oil is clean and full. The generator frequency specifications loaded and unloaded are correct. When it quits, I have opened the carburator fuel drain and fuel does drain. Any help would be greatly appreciated. Thanks.

DAN L · 07-08-2009, 02:42 AM

is the air filter clean? is the generator cover panel installed? what is the ambient air temperature when it quits? you need more than 1/4 tank of fuel. when it quits, will it restart immediately if you run the fuel priming pump? have you replaced the fuel filters?
check the onan website for troubleshooting info.

Clay L · 07-08-2009, 04:32 PM

I had a similar problem.
It turned out to be a loose clamp on the fuel line at the transition from rubber to metal at the gas tank. It allowed air to drawn into the line under vibration or road bounce thus killing the engine. The generator threw a number 36 error code as I recall.

cvrvr · 07-11-2009, 07:20 PM

I have had the same problem. Three times my genset has shut down. Every time it was very hot. Once I found the cover had come open. According to Onan they don't have any kind of high temperature shut down device.

Since I installed a padlock hasp on the cover to keep it from coming open, I haven't had any problems.

George

LVJ58 · 07-11-2009, 09:58 PM

I would suspect fuel line/filter problem or electric pump going bad.

RV Wizard · 07-12-2009, 03:32 AM

You may also want to check connections; especially ground.

ALAG321 · 07-12-2009, 06:27 AM

Also check the section of fuel line that is rubber. I had a 1986 RV and finally found the problem was small cracks in the fuel line allowing air to suck into the line, causing erratic rpm's with stalling problems.