onan 5.5 Marquis hard starting

Question

I recently Purchased a 2000 holiday Rambler with an Onan generator with 350 hours on it. When I try to start it, it surges for a few moments, then dies. if I take the air cleaner off and give a very brief shot of carb cleaner about every 5 seconds, it will keep running, eventually it evens out and runs fine. This morning after a few minutes of trying to start it and keeping it running by playing with the throttle I let it die. Came back about 15 minutes later, it started right up and ran fine. Any ideas? Leaving on a trip next week and want to make sure it will run ok.

gbopp · Answer

Try changing the fuel filter(s).
Clean/replace the air filter.
Check the oil level.
Make sure there is sufficient fuel in the MH tank.

If that doesn't help, run Seafoam through the generator fuel system.

othertonka · Answer

Try the primer button before trying to start. The primer button is the same as the stop button. Just push and hold down the Stop/prime and listen for the fuel pump to click and hold down until the clicking slows down, usually 15 to 20 seconds, This fills the carb. bowl. Then push the Start button. should start within 30 seconds. It is best to do this at the Gen set itself so you can hear the pump clicking.

jluke · Answer

Thanks for the input, will try the "priming" routine tomorrow and will order a fuel filter. Just changed the oil, air filter is clean.

jaygee · Answer

Mine had similar problems and I unscrewed the drain at the bottom of the carb, sprayed the inside of the carb real well until the cleaner was running out of the drain. I let it set about fifteen minutes or more, close the drain screw, primed it and cranked it up. It solved my problem.

Worked for me, but your luck and results might be different.

lj2654 · Answer

sometimes a fuel line will get a small pinhole. That itself can cause a starting and running issue.

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onan 5.5 Marquis hard starting

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