Small Engines (Lawn Mowers, etc.): Briggs Gas in Oil Crankcase, malt beverage, free relaxation

Question
Briggs 22HP riding lawnmower, 2 years old.
Gas found in crankcase, completly full.  Engine will start and run for 10-15sec, black gas comes out of the exhaust, and white smoke.  Drained "oil" (black gass really) and refilled with oil, engine runs for ~30 sec and again black gas comes from exhaust with white smoke.  

Answer
This is the same old thing different day. Actually third time today.
Read my past answers. Today the answer to Chuck would best help you.
But since I don't want you to feel cheated I'll throw a little humor your way.

Did you know....
According to the "New York Times" in 2006 deer hunters in New York state killed 263,111 deer... and 6 hunters.

Clean the carb. It's leaking over, leaking through the intake valve and filling the crankcase.

After you clean the carb you will still have black soot and white smoke coming from the pipe. It will take awhile to burn all of the oil out of the muffler. After the clean, start the engine grab a lawn chair, a cereal malt beverage and enjoy some mosquito free relaxation.