ONAN runs, stops, starts again

[TexasUltra]

I was exercising my ONAN 4000 the other day as I do monthly and after about 45 minutes it just shut down. It re-started after a couple of minutes, again after 30-45 minutes before shutting down again. One more time before I decided there was a problem.
I pulled it out of storage this afternoon and checked the oil level and quality and it was fine.
Started it again and boom same thing. I didn’t have the sequence of how to get the trouble code with me so I backed it back in to storage.
I use a fuel stabilizer and premium fuel for the genset at all times.
I will try to get the code on Saturday but is there anything else I could check when I have it pulled out?
It seemed kind of hot in the compartment but it was only about 75 degrees today and we’ve run the genset in 95-degree weather with no problem.
MOD: 4KYFA26100K
SER: H050816555
SPEC: K

[Sam_Spade]

TexasUltra wrote:

I use a fuel stabilizer and premium fuel for the genset at all times.

So called "premium" fuel is a waste of money in a generator......and anything else that doesn't specifically require it.

Your symptoms sound a LOT like mine when the fuel pump failed.
It would start and run fine......until it got hot, it seemed.

[rrupert]

Have you had a tuneup done? There could be crud in the carburetor. Also, if you can get ethanol free gas it would be help. Small engines don't get along with either.

[1995brave]

Check the air filter, fuel lines (as stated above).
Have you changed gas cap? Sound like you are sucking fuel from the tank, but the used gas is not being replaced by air (tank sealed to tight)Loosen the gas cap and see how long it runs.

[enblethen]

Even though you have checked the oil level, if your Onan has an oil level switch it could be bad.
Can you tell if oil is foaming? This could also cause oil level or oil pressure switch to shut it down.
Along with "whemme" post the fuel pump could be sucking air through decaying rubber line.

[whemme]

My opinion. You may have a fuel pump getting weak.