billyO Posted January 19, 2015 Share Posted January 19, 2015 Hello all. Hope 2015 is treating y'all well. I have (hopefully I can still say that instead of "had") the above mentioned welder that worked well until last summer when I was working on my dog carrier that I posted pics of last summer. When I finished welding the brackets to the frame, I turned around to see oil spraying all over my shop. Well, life got in the way and I wasn't able to do anything with it until this weekend. I was going to fire it up again to see if I could see where the oil was coming from, but when I pulled out the dipstick to see how much oil was left, I saw/smelled gasoline in the oil reservoir. I was thinking blown head gasket or cracked cylinder, so I did a compression test today and one cylinder was at 120 psi, and the other at 115 psi. I found that they should be between 100-120 psi when the engine is hot. Where to go from here? What's the difference between hot v cold compression? Thanks Quote Link to comment Share on other sites More sharing options...
Grant Posted January 19, 2015 Share Posted January 19, 2015 good morning all billyO - The Onan generator in our motor home has both an engine driven manual fuel pump and an electric fuel pump closer to the tank. If the diaphragm in the manual pump is ruptured the electric pump can pump raw fuel through the rupture into the crank case. If there is raw fuel in the crank case there must be some common communition point up hill from the carburetor and under pressure to get the oil / gas mixture to spew. -grant Quote Link to comment Share on other sites More sharing options...
jmccustomknives Posted January 19, 2015 Share Posted January 19, 2015 Grant is correct about the manual fuel pump, sounds like your problem. You may also need to adjust the valves if it has never been done. Quote Link to comment Share on other sites More sharing options...
swedefiddle Posted January 19, 2015 Share Posted January 19, 2015 Gasoline in the oil will dry out the cylinders, causing slightly lower compression. The piston rings are NOT YOUR PROBLEM, unless you ran it for a LONG time. Grant is correct, there is a problem with either a fuel pump or a float valve in the carb. Quote Link to comment Share on other sites More sharing options...
billyO Posted January 19, 2015 Author Share Posted January 19, 2015 Thanks for the replies, guys, I bypassed the mechanical fuel pump last summer so I guess that points to the float valve in the carb, eh? Quote Link to comment Share on other sites More sharing options...
billyO Posted January 25, 2015 Author Share Posted January 25, 2015 Hi all, the saga continues... Today I had the time to do a bit with the welder. Drained the oil/gas and replaced it with new oil. Cleaned it up as best as I could to locate the leak and fired it up. It fired up and no oil spurting, so I let it idle. It idled for approx. 12 min, then started hesitating on and off for a few minutes then died (no oil leak detected). I took the dogs out back to check on the cows and cracked a beer, and 30 min later fired it up again. It idled for approx. 30 min, started to hesitate under load, so I messed with the spring attachment to the vacuum booster and choke and it seemed to run fine, and idled for approx. 45 min. before I shut it down for the evening. The only oil leak I noticed was a slow drip that seems to be coming from the gasket between the engine and the generator. No fuel in the oil as far as I can tell. Could the gas in the oil have been a one time situation? I plan on trying some welding tomorrow to see how it does under normal use. Any thoughts worth sharing? Thanks for the efforts so far... Quote Link to comment Share on other sites More sharing options...
SoCal Dave Posted January 26, 2015 Share Posted January 26, 2015 I would definitely test it under load just after it warms up a little. I doubt that the fuel in the oil is a one time thing. Why would it happen one time. You mention gas. I thought Onan's were mostly diesel types? If it is gas, then it might be the carburetor. Good luck. Quote Link to comment Share on other sites More sharing options...
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