If your Tecumseh is a flat head HMSK100 it should have 26 oz. of oil in it.(above 30 degrees ODT. SAE 30) That is what it calls for in the Tecumseh engine manual. I put a little too much in a hs40 and had the same problem. HS40-HS50 hold 21oz even on a Rupp that the motor is on a angle. Too much more than that and it spits it out. I did it with a brand new motor.
when the crankcase keeps getting pumped with pressure (compression blowby) it's gonna try and force any suspended oil mist out the path of least resistance which is the breather.... when both valves are closed and it's coming up on compression the breather is the open path.....I'm not saying this is his problem but its possible..
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That's what the breather is for from the factory. To keep the valve train lubed with oil, while letting out crankcase pressure. But if he is getting to much coming out he either has way to much oil, or the valve guides are a little worn.
But it can be other problems, but that's the most common.
On perfromance most have to drill and tap fittings on the sidecover to release extra crankcase pressure. If not they will be getting way to much pressure from the breather.
But it can be other problems, but that's the most common.
On perfromance most have to drill and tap fittings on the sidecover to release extra crankcase pressure. If not they will be getting way to much pressure from the breather.
If its the intake valve guide it will suck oil into the combustion chamber causing a smoky exhaust and /or fouled plug, if it's the exhaust guide you could get some exhaust blowing by the guide into the breather box but the guide will have to be pretty sloppy to cause that much blowby.... Another possibility is the breather is partially plugged causing the crankcase pressure to build up....
I'm sure your Tec engine is about the same as mine as far as the breather is concerned. I was given the engine, which came off a parking lot sweeper. The engine block had just been replaced with a new "short block" so it's a really a perfect engine. However, it would blow oil out the breather even at low RPM. I took off the breather and noticed that the "reed" valve, that works as a one-way-valve, was slightly defective and not sealing the round hole that it covered. I drilled the rivets that held the reed in place, straightened it so it sealed better, and stuck it back on the engine.....no more problem at any RPM.