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revolutionryan's avatar
Aug 09, 2019

Onan gen shuts off after 5 minutes

I have an Onan7500 Quiet Diesel generator in my 2002 Fleeteood Revolution. More often than not the generator will run for 5 minutes and then stop. It will immediately start back up and run for another 5 minutes and then stop again. Sometimes it will do the same but for 8-10!minutes. Probably unwisely, I’ve done this over and over for an hour or two until it starts and doesn’t stop. At that point I’ve probably had it run all day for hours on end until I hit the stop button. All filters and fluids are changed regularly. Any ideas? Has anyone else had/have similar experiences? Not opposed to taking it to an authorized Onan service center to get it fixed as there is one not too far from my house. What I don’t want is getting the run around saying it could be this or that and spending lots of money only to have the problem still exist. Seems like it pulled a code that offered no diagnosis except to take it to in for service.
  • My guess would be low oil and the low oil sensor is doing its job. As oil is moving through the engine the level in the pan or sump decreases causing the sensor to see low oil. The engine shuts down and oil drains back down into the pan and now the sensor sees enough oil. Are you sitting level? Just being off a few degrees can lower the oil level in the area of the sensor. Check the oil and maybe add a few ounces if it doesn't show completely full.
  • Fuel pumps seem to be a common failure item around 10 years old.

    My Onan (Cummins) dealer treated me right.
  • Fuel shut off valve sticking? Clean shut off valve. Hole in gas line? fix line. Gas cap not venting? Change gas cap. Bad fuel pump? change pump. Defective circuit board? Change board. Low oil? Put more oil in.

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