Onan 4000 shutting off after 20 min.
Have an Onan 4000 300hrs in a Class C. If I'm sitting still it will run about 20 minutes then sputters and sounds like it's running out of gas and shuts down. If I wait a while it will start back up a...
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I have had my 4BGE Spec G do this twice.
First thing I would recommend is you get yourself an inline spark tester like this:
https://www.amazon.com/gp/product/B0002STS4O
When the generator refuses to start/run, put this inline with the outboard spark plug and see if you are getting a spark. I bet you are not.
There are two primary suspects - the coil and the ignition control module (assuming you have electronic and not points ignition).
You can get aftermarket coils on Amazon for about $35. Ignition control modules run $100+.
I sent my voltage regulator and control board off to Flight Systems, who will test them for $35 each. If you end up buying a replacement part from them, they waive the testing fee. Both boards are ~$200 each.
It's also possible that the fuel pump is dying.
For me, it was either the ignition control module or the coil. I can't be sure which because when I was replacing the ICM the terminal on the coil twisted out of the coil so I had to replace it also. So I can't know which was the culprit, but it was one or the other. I'm pretty sure it was the ICM though.
Steve
First thing I would recommend is you get yourself an inline spark tester like this:
https://www.amazon.com/gp/product/B0002STS4O
When the generator refuses to start/run, put this inline with the outboard spark plug and see if you are getting a spark. I bet you are not.
There are two primary suspects - the coil and the ignition control module (assuming you have electronic and not points ignition).
You can get aftermarket coils on Amazon for about $35. Ignition control modules run $100+.
I sent my voltage regulator and control board off to Flight Systems, who will test them for $35 each. If you end up buying a replacement part from them, they waive the testing fee. Both boards are ~$200 each.
It's also possible that the fuel pump is dying.
For me, it was either the ignition control module or the coil. I can't be sure which because when I was replacing the ICM the terminal on the coil twisted out of the coil so I had to replace it also. So I can't know which was the culprit, but it was one or the other. I'm pretty sure it was the ICM though.
Steve
