RodT82721 wrote:

I just went thru that same type problem. Would start then died. Check the trouble code, mine was 3-6. I had to remove the Gen Set from the MH to gain access to service it. I was planning on taking it into Cummins.

After a lot of checking I found a dirty carburetor was the culprit.

What I did - First take the air cleaner out and while attempting to start, spray a little carb-cleaner into the throat. If it starts and attempts to run, then keep spraying small amounts, just enough to keep it running while verify it is producing 120VAC. This will prove that it is a fuel problem and not the control board.

Remove the fuel line at the carb and check for good fuel while cranking, if okay then the next step is to pull the carb and clean it. There are two 10MM hex head bolts thru the air cleaner assembly that hold the carb to the manifold.

The Onan service manual says no overhaul just get a new carb.

I took mine apart. It is a very simple carb. The fuel shut-off solinoid holds the bowl on. Inside are a float with attached needle valve and the air-fuel mixture valve, (labeled as the altitude adjustment.) The air-fuel mixture adjustment was my problem, the needle valve and seat was a little dirty. I tried cleaning without removing it and then the motor would run, but was surging bad and would die under full load. So I took it off again.

To get this needle out you have to pry the plastic altitude adjustment knob (a press fit) away from the bowl enough to allow unscrewing the needle valve all the way out, its spring loaded. (Count the turns so you can return it to the same setting after cleaning.) Then spray cleaner into the all the holes and clean everything good.

After doing that it now starts immediately and runs like new. Ran it for over an hour under full load and never missed a beat.
Made my day..