Toro Rider with a 19Hp Kohler Courage Engine. Its about 7 or 8 years old. This year, right after I start it up, and move about 100 feet down the lawn, it starts to smoke badly for a minute or 2. Then it stops smoking, but may come back 1 or 2 times as i cut my 1/2 acre lot. By the color and smell, it seems like oil burning.

I did the winterizing today and found the oil to be clean and completely full on the dipstick.

Otherwise it runs fine and starts right up. If it weren't for the smoke i wouldn't suspect a problem.

Any suggestions?