So , I keep having issues with my Onan just randomly shutting off. When I try to re-fire it up, it hits like it got fuel , but it immediately dies again . It looks like it flashes 3 times. I have already tried replacing the oil pressure switch. Oil level is good. Any other ideas? Thanks .

When it is flashing three times, you need to press the Stop switch to get the real 2 digit trouble code. Two flashes, then a pause, followed by six flashes would be trouble code 26, for example.

You may want to check your coolant temp sensor. Common problem.

You will probably see a fault code of 36, which is unknown issue that caused generator shut down.

If so, this is a sign that the circuit board is not supplying the low-pressure fuel pump any voltage. That is an easy fix to supply voltage to it a different way.

How old is it…

2003

Years back my onan5500 belt broke. It would run if I held the start button in - could feel the exhaust getting hot. But would die as soon as it stopped cranking. I noticed in the back the stator, maybe its called was not rotating. Pulled it out, wasn't that bad with two jacks and some wood to span. Buddy and I redid belt and pully. Worked great. Other thing to keep in mind is keep eye on the lash. Mine was after several years starting to bog down and take a while to run smooth after startup. Fixed the gap - again really easy just like car. And ran great. I used it every weekend the entire weekend. Had close to 4k hours on it.

I have diesel one now in my Renegade. Doesnt even had a cover you can remove easy - need to look at it and familiarize myself with it.

Also at one point I bought a new carb for it - worth the month they are only 40bucks on amazon and kept old one as spare.

it may also be the inverter is bad,seen it before
it can be sent for repair.i believe the company is flight systems

quote:

Originally posted by Mike Frizie:
2003

I guess I should have asked if it was a diesel or gas model.

quote:

Originally posted by WHOMPWHOMP:
How old is it…

IMO then you need a $800 control board …10 years is life expectancy…..check out FLIGHT SYSTEMS…

Did we ever get an error code on the generator?

So, here's my take if it is a diesel. As WhompWhomp said, it could be a control board losing power to the lift pump, but before you try that, try this:

If it is code 36 then you need to wire in a relay that gets power from the start/stop switch to activate. The wire is the top right one and I believe it is the one that lights the switch when it starts. This will be the signal wire.

Get 12-volt constant from the power coming into the generator on the back or find 12 volts constant in the wiring inside for the power side of the relay. Ground the correct terminal, then run the fuel pump wire to the output terminal.

Every time the generator is commanded to start the relay will power the fuel pump. When you shut off the generator, the relay will lose its signal power and shut off the pump.

I do this service at the track quite often, but it isn't that difficult on your own. Nothing is worse than losing your generator when it is 100 degrees out. I know, and I had to learn a lot about Onan generators because of it.