Small Engines (Lawn Mowers, etc.): Lawnmower repair, briggs and stratton, piston ring

Question
Hi Michael,
I hope you can help me.  We are having a problem with our mower.  It's a Briggs and Stratton 4 hp, Yard Machine.  We have had it less than 2 years and paid almost 200.00 for it.
Anyway, the problem is that it is hesitating and blowing smoke out of the side of it when we push it.  The engine sounds awful, but it doesn't stall. It just kinda sounds like it is revving up.  The smoke is black, as if we are burning oil.
The spark plug is good, the gasoline is good, and it had oil.  Can you possibly tell me what may be wrong, or what to check for?
Thank you very much.


Answer
Hi Melanie,

Your problem is very unusual. First, make sure that the oil level is not overfull.  You are right, black oil usually indicates burning oil.  Next, I would do a compression test to check for a cracked piston ring.  Other than that, I can't think of what else could cause this.

Let me know how you make out.
Michael