Onan 7500 generator cranks but won?t fire

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New member
Nov 13, 2018

I am new here. I have an Onan 7500 gas generator that I use in my Ford E450 van which has been converted for mobile grooming.

I am having issues with my generator cranking but not firing. The following have already been replaced:

Fuel pump
Fuel filter
Spark plugs
Oil changed and new filter
Spark arrestor cleaned

I do not believe that the fuel pump or lines are the cause of the issue, as I can hear the fuel flowing freely when priming, and the pump was replaced in June. The engine will crank repeatedly but just won?t fire. I?d also like to add that this problem is intermittent. Some days it will fire right up and I?ve never had issues with surging or loss of power once on. It can hold the load just fine (lighting, AC, high velocity force dryer, tv, microwave can all be on and no issues)  Other days it will crank and nothing no matter what I do.

The one thing we have noticed is that the generator seems to be very sensitive when it comes to the oil level, and after filling the oil within days it is already on low. No noticeable leaks, and using the correct type of oil.

Any suggestions or input? I have contacted a local onan certified shop but am waiting for them to call me in for service. For now I am able to plug in to homes to work, but would obviously like my generator running smooth.

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