Toward the end of the mowing season, this engine would smoke (white smoke) for about a minute on mostly the first startup of the day. Other times it would smoke in the afternoon after doing 4-5 yards. It will idle and run fine after that. I've noticed now that there is oil in the air filter box on the front of the motor. About a tablespoons worth. I'm not a mechanic and a search of this forum hasn't turned up any similar posts. Can someone give me an idea of what the problem may be? The mower is well used (no hour meter) but is also well maintained which means daily maintenance checks (oil, grease, air, etc). The engine is a manual start, hydro unit, 48" cut. Thanks for your input. Have a great Holiday!!