Kohler ch20s leaking oil out of exhaust seals

Hello,

I recently found my kohler ch20s to be leaking oil out of the exhaust gaskets pretty bad. I can tell you that it was overfilled with oil and ran for some time like that. (Thanks son) Anyhow I originally thought that the excess oil had blown the head gaskets, so I changed both. While I was in there, I decided to reseat the valves and replace the intake valve gasket. Everything is put back together and it runs just fine. In fact better than I expected. My question is, I removed the exhaust to get a peak at.the valves and noticed oil was dripping down the exhaust valve again. Great! Then I noticed that oil was pooled up in the valve cover/ fill area. My question is. Shouldnt the oil drain down to the pan? It appears that the oil built up in the valve cover area is not draining and thus leaking down into the exhaust valve and so on. There is no seal on the exhaust valve just the intake. Like I said everything is running smoothly, however I just want to make sure this isnt a problem before I put it back to work. Thanks.

The reason only the intake valves has seals is that they go trough the vacuum part of the head and will draw oil. You do want some oil into the valve guides so they don't wear out. Badly worn out valve guides will make a engine burn oil and smoke.

What would cause oil to leak out of both exhaust seals?

AHtex said:

What would cause oil to leak out of both exhaust seals?

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I have no idea what you mean by exhaust seals. The only seals I can think you are talking about are the exhaust manifold to head gaskets? If you are talking about a oil leak at this gasket when the engine is running you must have a lot of smoke??? As I said earlier its normal for the valve guides to have a small amount oil to leak by for proper lubrication.

Yes, oil is leaking from the exhaust manifold gasket on both heads. This is the first small engine ive ever really torn apart, so its a learn as I go experience. I get a little grey smoke when I fire it up, but I wouldn't call it excessive. I did pull the plugs and noticed oil fouling on one and carbon build up on the other. They were both new.

AHtex said:

Yes, oil is leaking from the exhaust manifold gasket on both heads. This is the first small engine ive ever really torn apart, so its a learn as I go experience. I get a little grey smoke when I fire it up, but I wouldn't call it excessive. I did pull the plugs and noticed oil fouling on one and carbon build up on the other. They were both new.

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The exhaust valves are on the bottom of the engine so they would get more oil then the intake valves. Are you sure you don't have a valve cover leak? Seeing its of the bottom of the engine its got to be hard to see where the oil is coming from a hot engine. You did clean all the surfaces really well when you replaced the head gaskets and use proper torque to tighten all head and valve cover bolts. As I recall that engine has different style valve covers also and it can be tricky to make the o ring style fit into the plastic covers groove if you have that style?

Yes, the engine sits vertically, or upright so the valve covers are at the top. It is on a bearcat chipper/shredder. I could visibly see oil coming out of the exhaust manifold. I took my time cleaning and properly setting the torques. The valve cover gaskets were a pain to reinstall. I do think ive made a break thru. I peaked inside the oil fill port on the head and noticed oil pooled up inside. It appears the drain back hole is clogged. This is allowing oil to submerge both of the valve guides, and probably leak excessively into the combustion chamber?

When you open the valve covers you just see little to no oil at all. You need to clear the passageways for oil to return to engine.

Well, I just figured out the problem. Looks like it has the wrong heads on it. No way for the oil to drain back. It just collects in the valve cover and eventually finds its way through the valve guides into the combustion chamber and out the exhaust. I guess thats what you get when you buy a used piece of equipment. That problem was not in the service manual. Haha. Thanks for all the help.