Onan generator shuts down

[tacgle]

I have an Onan Marquis 5500 Generator on my 33R, 2002 Fleetwood Bounder that runs for approximately twenty minutes and then randomly revs up and down, then shuts off. It seems to last a little longer if the motor home is in motion and/or in heat.
I am aware of the ¼ gasoline tank tank automatic shut off and have made sure the tank was full. I have also changed the oil to the recommended higher viscosity of 15W 45, replaced the air filter, removed the oil pressure sensor indicator, and even loosened the gas tank cap, because I had read of vapor locks. None of this has worked. I am not sure if I have a fuel delivery or electronic problem.
The Fault code is 36, which means, “Engine Stopped without Command” (really, it says that!). I have even called Onan and they aren’t sure what it is.
Has anyone else experienced this? Suggestions?

[Jim]

Lots of people that have this 20 minute shut down problem change the fuel filter right off. If that doesn't do it, then disconnect the fuel line and put it into a can of gas. If the rubber fuel line on top of the fuel tank is leaking, drawing air, that can give your symptom.

Why it can repeatedly take 20 minutes for the problem to show up is a mystery to me. Or I can't remember what others have said about it.