My mom just moved to a place where she needs to cut her lawn, so I found a self propelled mower that needed a little work on a local forum, $5. It was stripped, no blade, no blade adapters or bolt, no belt, no air filter or air filter cover, ran really rough. I bought all those things, being the nice daughter that I am, including a new carb, which I put on myself. It still runs kinda rough. Puffs a little smokey stuff here and there. I'm not a small engine repair guru by any means, I am a computer technician, but I figured if I'm handy enough to replace tiny parts in laptops, I can work on a small lawnmower too. Any suggestions would be much appreciated!!
The next question would be what color is the smoke. Black means it is running rich, and would be a fuel problem. blue would be oil, but sometimes can be a white/grey. There may be a reason that it was stripped the way you found it.