Small Engines (Lawn Mowers, etc.): Rider mower engine/oil issue, oil plug, compression ring

Question
All of the following happens after a couple of passes in the yard. I have smoke and oil coming out the exhaust. I have oil in the air filter. This is what I've done so far: Checked oil levels to make sure there is no overfill.(None- a little low actually) Pulled plug; and turned over the motor to see if any oil was in the chamber. (No visible oil; plug was black and crusty, not wet at all.) Changed the plug. Changed air filter thinking that it may been clogged and drew some oil up into the carb. No visible leaks and have good compression. Still smokes and draws oil through the breather into the air filter/carb. I'm not at all a mechanic; did all this through the advice of others. Is there anything else I should do; any other areas to check. Craftsman 17hp rider. Engine: B and S....not sure of model?

Answer
 Hello Steve

 Sorry to have to tell you this, but the Engine has a Cracked Compression Ring. From what You Wrote Compression is going into the Crankcase and pushing out through the Crankcase Vent and into the Carb and Out Around the Exhaust Valve Stem.

 Good Luck

 Respectfully

 John