Onan 4000 Microquiet quits

[Firedogs2]

I have an Onan 4000 microquiet generator in my 2008 JAYCO Melbourne 29D. For many years, I had no problem with it at all, but recently it has developed one. It starts and runs fine - as it should- if the temperature outdoors is below 72-75 degrees. Above that, it will start, run for a short time and quit. It will not restart until it cools down, and if the temp stays above 75, it won't run at all. It is apparent that this is a heat related problem, but how to solve it is a mystery. Anyone have the same problem? Any suggestions for fixing it???

[LI-Camper]

I had the same generator in my 2004 Jayco Greyhawk. It also ran for a short time and then quit. It was the electric fuel pump. It was located on the left side of the generator.

[Hittntheroad]

They actually make a vent especially for the 4000 that draws fresh air from the side of the generator. Without the vent, it draws hot air from underneath where the motor and exhaust are. It’s a known problem. I installed one and fixed my generator on my Thor. The rubber boot forces it to draw air from the side.