Small Engines (Lawn Mowers, etc.): Leaking Oil, briggs stratton engine, briggs stratton

Question
I purchased a Toro (Briggs & Stratton Engine) model 20041 approximately 15 months ago.

Suddenly, it has begun to emit a strong flow of black smoke when it it running which I believe is because it is burning oil that is leaking from somewhere.  I can't see any obvious source.  Any ideas of where to look and how to fix it?

Answer
 Hello Michael:

 Check the Air Filter. Is it Clean? Is there Oil inside the Filter or Carburator Throat? If Yes, then the Crankcase Vent is Not Working and May need to be Cleaned. Send me the Model, Type and Code Numbers Off of the Engine, Please. With these I can Locate a Breakdown and Better Assist you. The Carburator May Flooding Slightly Also. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. I enjoy knowing the Outcome. Thanks.

 Good Luck

 Respectfully

 John