Onan 5500 Quits after few minutes

[JDickson]

Looking for some help on an Onan Marquis Gold 5500 Generator
It starts and runs for a few minutes, then stops and won't start again until it's cool down. I can't see where it would get that hot that it shuts down from overheating. It shuts down with or without a load on it.
What should I check or look for?
Thanks for any help you can give.
Joe

[wyo700]

Does it run off of gas or propane. If gas it could be vapor lock. Open the gas cap and try to start again.

[JDickson]

Thanks I'll try that. And yes it is gas...

Joe

[JDickson]

Hi Again, As they say, Back to the drawing board.
Tried it, that didn't work.
Open to whatever may be next.

Joe

[OldCoot]

Originally Posted by JDickson

Hi Again, As they say, Back to the drawing board.
Tried it, that didn't work.
Open to whatever may be next.

Joe

Could be the float in the carb is sticking or a gas line is collapsing.

[wyo700]

Originally Posted by OldCoot

Could be the float in the carb is sticking or a gas line is collapsing.

I agree or check for a fuel filter. One other thing have you been putting fuel in that contains ethanol. That will give you problems. If you have get a bottle of sea foam and poor it in your tank and keep trying to run it. Probably needs a good cleaning. Pull out the spark plug and check the gap and clean it maybe replace it.

[JDickson]

Thanks Again, I'll try all of the above, but boy it was running great just before it became a piece of _ _ _ _ you can fill in the blanks. lol

Joe

[djorgensen3]

Those generators are known to have a crappy fuel pump. I had to replace mine with a Mr.Gasket low pressure pump from Oreilly's. As soon as I put that on, it has run like a dream. Do not buy a factory fuel pump as it will have an issue too not long after you put it on. Also buy a can of Onan Decarbonizer spray and follow the instructions and it will clean up the pistons and combustion chambers nicely and it will run like a dream!

[F and E Damp]

I have a similar problem, except mine starts but only runs for about 5 seconds, spitting clouds of smoke, then quits. When I first got the rig, using the prime button only caused the fuel pump to click for maybe two seconds. Now it clicks for as long as I hold the button down.

I suspect that either the float no longer floats or the float valve is not shutting off. My fuel pump is a new one from NAPA, specifically a 4 psi max pressure for carb-equipped engines, and the filters are new.

More detective work needed!

[Taxman]

Check for broken wire. I had similar problem, tried all the usual fixes (such as spark plug/wire replace, fuel filter replace, etc.). Finally found it to be a broken wire from the electric fuel pump.

[cliff7122]

Do you have the model number for that pump? They list one that is good for 2 to 3. 5 psi.

[cliff7122]

Originally Posted by djorgensen3

Those generators are known to have a crappy fuel pump. I had to replace mine with a Mr.Gasket low pressure pump from Oreilly's. As soon as I put that on, it has run like a dream. Do not buy a factory fuel pump as it will have an issue too not long after you put it on. Also buy a can of Onan Decarbonizer spray and follow the instructions and it will clean up the pistons and combustion chambers nicely and it will run like a dream!

Replied to wrong thread. Do you have the model number of your Mr. Gasket fuel pump?

[gsbuick65]

could be the coil, thats what my generator is doing, starts up runs for few seconds then cuts off, I checked the spark after it quit, no spark.