The engine has 1200 hours,has always smoked occasionally when started. Now it wants to fill the muffler with oil and if you leave it set a couple of weeks and start it , it blows oil out passed the oil filter gasket. I plan to put rings in it. Here is my problem I started a different mower yesterday (new 15 hours, sat all winter) oil has leaked out of it and it had blow by when started. Any ideas why?