Onan 16 hp on lincwelder 225

[Dave Jensen]

Getting way to much oil up in the breather tube to carb cloggs filter any help would be great Dave

[Dempster]

Sounds like worn pistons and rings ? Too much back pressure in crankcase and not enough compression from being worn out.

[Dave Jensen]

Thanks i did a compession test today 120 both cylinders but tommorrow im gonna pull dip stick ans see if there is presure yhink i need a rebuild job

[Ray Griffiths]

Dave,
Ask over in the Onan generator forum or do a search there - there are millions of Onan generators around and the resident smart guys there may have some suggestions. I saw a reference to this on a genset recently but can't remember what they said now.
Ray

[The Engine Shed]

Hi Dave
I purchased one of these welders several years ago from a company that said it needed a engine rebuild (it was blowing oil out of the crankcase breather) , when I got it back to my shop I checked it over and found the oil way over the full mark , I drained the oil and refilled the crankcase with new oil to the proper level and started it , it ran perfectly , didn't use any oil and ran and welded fine. The problem was that someone over filled the oil !
With 120lbs of compression I would not suspect that it needs a rebuild , clean oil and the proper level when hot.
Good luck with it.
Tom

[Bill Geyer]

I have no experience on that Onan, but there is probably a one way breather valve some where to maintain a vacuum in the crank case. It could be broken, or inoperative.

[Dempster]

Might have chunks of carbon come off inside engine too just gunking it up if been sitting a long time. Onan recommended to pull the heads and clean them every 200 hours.

[doug hodgson]

clean breather check valve fill to correct oil level and weld to your harts content

[Stimw]

If you find oil overfilled MAKE SURE it is not contaminated with gas. Sometimes a carb problem will let gas enter the crankcase.