Small Engines (Lawn Mowers, etc.): small engine problem, vent tube, breather tube

Question
I have an older Tecumseh 6 h.p. engine on a tiller.  I replaced the air filter and after a short time, it is soaked with oil.  What is causing this?

Answer
How old is the engine?  Check the oil vent tube, some Tecumsehs are conntected to the air cleaner and some aren't.  Anyhow, oil can soak the filter if the valve breather is defective, and the valve breather tube is vented (connected) to the air cleaner/carburetor.

Have you changed the oil recently?
Let me know.
Eric