Small Engines (Lawn Mowers, etc.): oil in carb?, worn piston rings, crankcase breather

Question
My briggs engine is blowing a mist of oil from the crankcase breather into the carburator which saturates the filter and fowls out the spark plug.
The oil is fresh, level is proper, the breather unit replaced. What's going on?

Answer
Hi wrzep,

Since the oil level is correct, I suspect an overpressured crankcase.  This may be caused by worn piston rings or valve guides.  Do a compression test.  Also try running with the breather tube disconnected to see if the oil still vents out.

Let me know what you find.
Michael