My Onan on my recently purchased 88 Southwind would start every time, but only run for about 10 seconds. It would start over and over, but only run for a short time.
I tried some of these fuel solutions, but got some great advice on this forum, which I will pass along now...
Mine has an electric fuel pump, and I found that the power to that pump is not proper. The great suggestion was made to me here, that I might try a different 12 volt source for that pump.
I did. I took a lawnmower battery, and supplied a good solid 12 volts to that pump, and the generator fired right up, and stayed running.
When running, a multi meter showed that the voltage on the original wire to that pump is all over the place.
I ran the inverter for several hours break in, and it runs much better now. I also added sea foam (a fuel cleaner additive) to the the gas tank, but that 80 gallon tank feeds the whole camper.
I have since gone back to the original wire. It starts great, and nearly stalls every 10 or 15 seconds for the first couple minutes. Then it runs well.
I hope this helps on some level. I wish you luck with that carb. If you get that perfect and still have an issue, you may want to look into the power to the pump.
Karl I. Sagal KarlSagal@Gmail.com
Well done is better than well said. (Ben Franklin)
1988 Fleetwood Southwind, 34'