Why does my engine smoke when operating

leighann wheeler, you did not tell us which engine your mower has, or what color the smoke is. this is actual important to properly trouble shoot your engine. Here are some general solutions you could try first. Gray or white smoke is usually caused by oil burning, and a blown head gasket, worn pistons and rings, bad valves, or an engine that has to much oil could cause gray or white smoke.

The cause for dark colored smoke is usually excessive amount of fuel to the engine. If your mowers smoke is dark colored, check the air filter first. Make sure the air filter is clean and without obstruction. A plugged air filter will literally choke the engine and use more fuel. If your filter checks out okay,check the choke on the carburetor. If the choke is sticking the engine will smoke and also run rough. If your filter and your choke are okay, check the needle and seat in the carburetor. It may not be regulating the fuel level in the float bowl. I would try to clean the carburetor and set the jets properly. Of course, you also want to make sure that your spark plugs are okay, and of the right size. You can try to do a leak down test as well as a compression test. That would tell you if you are having valve and/or ring issues. Hope this helps to get you started in the right direction. Good luck.