chrisdug wrote:
Looking further into this - I think my nice new fuel pump (Onan part) does not pump after about 3-5 minutes. When I let the motor run until it stops and then manually press the Stop/Prime button - no fuel pump activity can be heard. Wait 5-10 minutes and it pumps just fine. Also, it pumps hard to fill the float bowl and then gets quieter as it stops moving the piston inside the pump.
Who make a pump for these that will live and continue to work? Temp on the pump only goes up a few degrees in 5 minutes run time - no way should it be seizing up due to heat.
Anyone else had this issue?
We have the same model Onan and had the same symptoms. It would run for about 10 minutes then surge and shut down just like a lawn mower that runs out of fuel. No sound from the pump with the stop/prime button after the shut down. If I waited a for maybe 1/2 hour, the pump would again run and the Generator would start and run another 10 minutes and quit again. After replacing the pump it has run fine since - for over 300 hours.
j-d may be correct about a problem with the control board. If you can get to the wire that runs the pump there is a spade connector that connects it to a wire from the control board. Disconnect the spade connector and use a test lead with alligator clips at each end to connect the end of the wire from the pump to one end of the test lead and the other end of the test lead to the positive cable from the house battery. This bypasses the control board. If you do this right after the generator surges and shuts down you can verify whether the pump or the control board is the issue.
In the picture below, the single wire at the bottom right is the fuel pump wire. When I replaced my pump I pulled it up to make the spade connector accessible. Take apart the spade connector and connect the pump side of the connector to the large red cable at the bottom left using the test lead to see if the pump runs.
