onan gen.

I have the Onan 5500 which does the same thing. I will let the starter rev for about 10 seconds, let it rest about 30, and repeat until it starts. I think the fuel is siphoning back into the main fuel tank leaving the gas line and the carb. dry. I thought about using the squeeze bulb like they have for boats but not sure what problems it might cause.

My onan 5500 has a primer, how old is yours?

You might check or just replace any rubber fuel lines in the genny and between the genny and the fuel tank.

Meny times, pinholes in the fuel lines will let sir in and cause the problems you are having.

When they start letting fuel out, the problems get worse.

gone2dadesert wrote:
My onan 5500 has a primer, how old is yours?

1998

On the Onan 5500, you press and hold down the STOP/PRIME button on the gen set itself and you will immediately hear the electric fuel pump start to click and hold it down for 15 or more seconds or until the clicking `slows down, it should be primed now, then release the button and push the start button. It might take 10 or more seconds to start. If it doesn't start, let off the start button and let it rest a few seconds and try again. Good luck. Prime

Got a fuel filter you can see if there's gas? If not I'd put a clear plastic inline one where I could see fuel flow.

JimM68 wrote:
You might check or just replace any rubber fuel lines in the genny and between the genny and the fuel tank.

Meny times, pinholes in the fuel lines will let sir in and cause the problems you are having.

W
hen they start letting fuel out, the problems get worse.

I just looked and the fuel lines run on top of the tank.hope that isn't it.Looks like I would have to drop the tank to replace the lines.

othertonka wrote:
On the Onan 5500, you press and hold down the STOP/PRIME button on the gen set itself and you will immediately hear the electric fuel pump start to click and hold it down for 15 or more seconds or until the clicking `slows down, it should be primed now, then release the button and push the start button. It might take 10 or more seconds to start. If it doesn't start, let off the start button and let it rest a few seconds and try again. Good luck. Prime

My Onan is 5000 gen set,it don't have a prim button.just start and stop.It must have a electric fuel pump tho,maybe that is my problem

After I push and hold the stop button to prime mine it takes 30 seconds or more for the fuel pump to start.

bsandy56 wrote:

othertonka wrote:
On the Onan 5500, you press and hold down the STOP/PRIME button on the gen set itself and you will immediately hear the electric fuel pump start to click and hold it down for 15 or more seconds or until the clicking `slows down, it should be primed now, then release the button and push the start button. It might take 10 or more seconds to start. If it doesn't start, let off the start button and let it rest a few seconds and try again. Good luck. Prime

My Onan is 5000 gen set,it don't have a prim button.just start and stop.It must have a electric fuel pump tho,maybe that is my problem

The STOP is the PRIME button even though it might not be marked prime.
That is on most models anyway.