Onan generator won't start.

[dehnger49]

I have a 2004 Winnebago Sightseer 35N. The 5500 Onan generator will not start. I've tried priming it for 30 seconds as stated in the manual and it fires a couple of times and dies. I only have 1/4 tank of gas. Could that be the problem? Any ideas? Thanks

[emiddleb]

Yes, quite possibly. Most generators are connected at or about the 1/4 level to the fuel tank. That way your gennie cannot strand you somewhere by draining the fuel tank dry. Gas up and try it again. If still a problem then check for fault codes etc.

[dehnger49]

Thanks Ed and Joie. I will fill it up and try that.

[Garrette]

May be the Onan fuel pump. My Onan 4000 had to have its fuel pump replaced.

[UFO Pilot]

If yours has not been changed, there are 2 fuel filters on the 5500. One is right before the fuel pump and the other one is right at the carb. The top filter has a replacement fitting that is used instead of the filter. The top filter on mine was leaking causing the Onan to starve for fuel under load.

[DAN L]

Originally Posted by dehnger49

I have a 2004 Winnebago Sightseer 35N. The 5500 Onan generator will not start. I've tried priming it for 30 seconds as stated in the manual and it fires a couple of times and dies. I only have 1/4 tank of gas. Could that be the problem? Any ideas? Thanks

my onan 5500 genny quits running at 3/8 tank of gas indicated on the dash qty gauge, about 28 gallons left. that works out right when i fill up the tank. my tank holds 75 gallons.

[Clifftall]

Originally Posted by dehnger49

I only have 1/4 tank of gas. Could that be the problem? Any ideas? Thanks

Yes

[dehnger49]

Thanks Emiddleb. I filled the gas tank and now my generator starts right up. I only had 1/4 tank, so you are correct, the gen fuel pump is set up higher in the gas tank so your MH engine does not run out of gas. I appreciate your help!

[dehnger49]

Dan L. Thanks for the info on the gas for the generator. You are correct, I only had 1/4 of a tank of gas. I filled it up and now my generator runs fine. Learn something new every day! I appreciate your help!

[frankdamp]

I wish my Onan could be fixed that easily! It's also a 5500, probably a 2001 model (MH is '02) with a carburetor. When we bought the MH, it ran very well and the hour meter showed 48 hours from new. We used it a couple of times the first season, particularly in Eastern WA in the summer, and I was careful to follow the "winter exercise" routine.

Just before Christmas 2010, I had cardiac surgery (four stents installed) and it was the best part of three months before I went out to the MH again, by which time the generator refused to start.

I've been messing with it on and off ever since, but it still won't run. I get a lot of backfiring when cranking and large puffs of white smoke out of the exhaust pipe when it backfires. Since we rarely used it when it worked fine, I've decided I'll wait until we're preparing to sell the rig, then get it professionally fixed.

A question for all Onan users:

The factory manual says DO NOT use ethanol-treated gasoline. Since the generator gets its fuel from the main tank, are you all traipsing around, burning fuel at 8 mpg, to find untreated gas at 30 cents more a gallon?

[Quaddinmad40]

Frankdemp

Do you have the altitude and season adjustments set accordingly. I find mine can be sensitive to weather and location.

In your area you are probably changing from sea level to high altitude in short order.