My 6hp MTD Yard Man with a B&S engine recently cut out on me. I'd thought I was stalling it with slightly high grass, so I did about 3 restarts and peeked underneath before it blew out a puff of black smoke and stopped starting altogether. After I tipped it all the way over, though, I noticed I had run over something like fishing line (thanks, neighbors!) that was preventing the blade from rotating.

The repair guy I talked to said it sounds like I may have gotten oil in the air filter when I tipped the mower to take a look. That's fine, but what steps should I now take to rectify this? thanks in advance for your help.

Take the air filter out, you may also need a new spark plug. Start if up without an air filter and let it run for awhile, it may smoke for 5 - 10 minutes or so, but thats alright. Don't mow or use it without an air filter in it. Once it clears up, clean up any oil in the air filter box and replace the air filter element, install the cover, check your oil level and add if needed..... You should be good to go...

might want to check your flywheel key after you do that and it still doesn't start