Small Engines (Lawn Mowers, etc.): smoke, breather vent, crankcase breather

Question
I started up my Troy Built Horse rototiller today. It started ok and ran good. After running for several minutes it started blowing out a lot of blue smoke out the exhaust. It did this for about 30 seconds then started to slow up. During this time the RPM did drop and ran a little rough. I tilled the garden and everything was fine. If I remember right last year it did the same thing. The oil level is just fine. Overall it is in good shape and since I got it (I got it used from a friend and know it was taken care of) I only run it about half hour or so at a time twice a year. I also change oil every year. Any idea what is wrong?

Answer
 Hello Bob:

 Check the Crankcase Breather/Vent. From your Description it Sounds like the Crankcase Breather/Vent is Sticking. Send me the Model Numbers Off the Engine, With these I can Locate a Breakdown/IPL and Better Assist you. I had a RARE Case where the Rings were Lining Up at Just the Right Time to Allow Oil to be Sucked from the Crankcase and Into the Cylinder During Intake Stroke. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John