Smoke from Craftsman Eager-1 6.75 hp mower

I have a Craftsmen Eager-1 6.75 hp mower with a 22" base and earlier today while mowing it starting billowing a blue smoke out the holes in the left side. I had the oil changed earlier this year, and this was my first time bringing it out. After shutting the mower off when I saw the smoke I checked the oil level and it was above full. So to be safe, I poured out all the oil that was in it and then put in new oil to the correct level. It started up fine, but after about fifteen seconds smoke started coming out the holes again, although much less than before. If allowed to run for any time at all, this happens and occasionally the engine knocks. Any ideas on how to stop the smoke and get it back running smoothly again?

 

The current smoke is probably a result of the previous problem. If it was overfilled the engine will blow oil into the breather system, if tilted in the wrong direction oil will end up in the breather system and they will all end up in the exhaust, so after the original problem is corrected the easiest solution is to set it in the back yard and let it run until the accunulated oil burns away. Have a good one. Geo