Generator runs sometimes and then shuts off. Replaced with new: Spark plugs, oil change, oil filter, air filter. "still no run" Replaced: New carburetor, New fuel pump, New fuel filter, No gas line hose from carburetor to fuel pump. "still no luck" The in line 10 amp fuse above stop/start switch is okay. The 20 amp two blade fuse by breakers is okay. I help "stop button" in for 15 seconds to prime Gen. and then hit start button and it started and ran for 60-90 seconds and then started getting rough and shut off and would not start. I ordered new 5 blade relay plug under air intake to see if that is problem. Are there any other in line fuses that could be problem Any suggestions would be greatly appreciated.

You need to make some friends at a local small engine shop. Onan engines are all over the place and they will probably have seen this before.Matt_C

Stop throwing money at it!Have you checked for spark at the spark plugs?Possible bad coil or plug wires.Does it make any attempt to fire? Any back firing?

thanks, I will check for spark. How do I get a manual for this Model (1997)

Is it making electricity when it's running?

Onan 5500 Generator in Holiday Rambler 1998 Endeavor

Matt_Colie
Explorer II
Jul 29, 2023
You need to make some friends at a local small engine shop. Onan engines are all over the place and they will probably have seen this before.
Matt_C
enblethen
Nomad
Jul 29, 2023
Stop throwing money at it!
Have you checked for spark at the spark plugs?
Possible bad coil or plug wires.
Does it make any attempt to fire? Any back firing?
dalefuji
Explorer
Jul 29, 2023
thanks, I will check for spark.
How do I get a manual for this Model (1997)
enblethen
Nomad
Jul 29, 2023
Check Ebay for manual.
johnhicks
Explorer
Jul 29, 2023
Is it making electricity when it's running?
dalefuji
Explorer
Jul 29, 2023
doesn't run long enough to check. Besides I had breakers turned off on Generator.
Rick_Jay
Explorer II
Jul 29, 2023
dalefuji,

Did you replace the gas line from the fuel pump to the gas tank?

If it ran when you primed it, you filled the float bowl with fuel and that allowed the generator to run for a short while. But with a leak in the line between the fuel pump and the gas tank, fuel can't be sucked up fast enough and the engine will stall.

One way to check is to take a line from the fuel pump into a separate gas container and see if the engine will keep running then.

Good Luck,

~Rick
LouLawrence
Explorer
Jul 29, 2023
^^^^This is what I would be looking at. An issues somewhere with the fuel line running from tank to generator. If it's sucking air along with the fuel it won't run for long.
dalefuji
Explorer
Jul 29, 2023
I took fuel line from fuel pump and stuck it in gas can and no luck still doesn't run.
I checked old carburetor and it seems clean and okay. I think the new carb. is stuck and not working properly.
Rick_Jay
Explorer II
Jul 29, 2023
dalefuji wrote:
I took fuel line from fuel pump and stuck it in gas can and no luck...

This could just be semantics, but to be clear, you need to disconnect the fuel line going TO the fuel pump, not from. That is, the fuel line coming from the gas tank. That's probably what you did, but just want to make it clear. To do this, you'll probably need an additional length of fuel line to drop down from the pump to the gas can.

I still think your symptoms still sound like fuel starvation.

Can you repeat your test where you primed the engine and then tried to start it? If that works, it's most likely a fuel problem.

When you go to start it, does it "pop" or show any signs of trying to start? Have you tried spraying any "quick start" spray into the carb to see if that would get it to "pop"?

~Rick