Small Engines (Lawn Mowers, etc.): Lawn Tractor Smoking Engine, craftsman lawn tractor, crankcase pressure

Question
Hello,

I just added oil to my Briggs & Stratton 17.5 HP (Craftsman Lawn Tractor.)  After about 10 minutes of cutting, a rather large plume of white smoke billowed from under the hood.  I raised the blades and let the tractor idle and the smoke stopped.  So I lowered the blades and resumed cutting and the smoke billowed again.  I did notice that I filled the oil a little past the "full" line - do you think I overfilled and that is why I am seeing smoke?  And why only when the blades are lowered and I am cutting?

Thanks for any insight.
Rayo

Answer
Hi Rayo,

Yes, I think you are right.  The overfull oil level is causing the smoking.  I would lower the level by draining a little oil from the crankcase.  When the engine is under a load it would build higher crankcase pressure causing the oil to be pushed out of the vent.

Let me know how you make out.
Michael