OK - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich - Lean - Rich - Lean – Rich

:beatdeadhorse:
exactly a backfire is caused by excessive fuel. Running lean is caused by lack of fuel... therefore no fuel no back fire....

Well I can't order parts from the onan site for a few more days. So until then, the tractor will wait.

What about doing a leak down test. Could unburned fuel be going in the exhaust causing it? Just throwing that out there. Onans are known for valve seat issues also.:Huh:

An exhaust backfire is basically unburned fuel. So, your right about that. A leak down test is not a bad idea. But I think it's a carb issue. Brent said the PO told him it started all at once, so unless a seat came out, I'm not sure it's just wear. Although, PO's do tend to exaggerate, and not always tell the whole truth. I don't think I'd go to the trouble of a leak down test until after going through the fuel system and doing a tune up. Just my :TwoCents:

Not a bad idea by any means Todd! :ThumbsUp:

I agree J, I was just throwing that out there. That's what I would also do first (clean the carb). IIRC the one I did I was able to reuse the carb gaskets.