On the way to Colorado in our '98 Southwind 35s back in June, we noticed the generator surging, then saw some smoke coming from underneath. After pulling off of the road, found that oil was all over the generator and compartment, and dripping from underneath. It was down over 1 quart.
We finished the trip without using it. Back home in Texas, I bought a service manual, and the troubleshooting guide suggested what I thought might be the culprit; the crankcase breather was probably clogged.
Without removing the genset, I managed to get the top of the casing off. It was a pain taking out all of those bolts around the back and left side, I think Onan obviously did that to discourage people like me. Too bad, I did it anyhow.
OK, so I checked the breather, it seemed to be fine. I didn't bother removing it, there was pretty good pressure coming out of the top of it. I also checked the exhaust for obstructions, none found.
I then cranked it up, and saw oil popping up out of an open hole on top left (toward the rear of the motorhome)of the engine assembly, nearest the muffler compartment, and realized I had stumbled across the problem.
Then, I googled it, and found a couple of threads here on RV Net where people had encountered this issue, and how they had repaired it.
I checked the hole, it was .750" (3/4") at the uppermost part, about 1/4" deep.
I found that Onan does make a replacement plug, part # 517-0293, but nobody around here stocks it.
At least one of the other folks reporting this had used a welch plug, so I located one (funny, as common as welch plugs are, very few parts stores knew what I was talking about, and only one had the 3/4" diameter). I've now had two good experiences with Bumper2Bumper.
I cleaned the open governor shaft hole with acetone, applied red Loctite on the diameter of the welch plug (if you ever install one, the dome top goes up, don't flip it where it is like a bowl).
after I centered the welch plug in the top of the hole, I placed a socket on top of it, then firmly tapped it down into the hole with a hand-held sledge hammer. It tried to cock to one side, but I persuaded it finally to go down evenly.
I then mixed some JB Weld and ran a bead around the sides of the plug.
Later in the afternoon, I fired it up. We now have our generator back, running and sounding like it did before. Kudos to those who had previously posted their experiences, it helped me to do it myself!
