Craftsman rear tine tiller won't start

My tiller model #917.299080 won't start. It sat for about 3yrs, with fuel. I drained the fuel, took off the carburetor bowl and cleaned it out(the bowl and nothing else), changed out some oil and filled it, changed the spark plug-still didn't start. Tested if we had spark by taking the plug out of the chamber, and trying to start, no spark. Friend said to make sure the flywheel was free of rust. I got to the flywheel and yes it was covered in rust, so I lightly sanded it and the contacts. The broken spot with the shiny metal plate had no rust. I put it all back together and still no spark! Help! I have no problem doing the work, I just don't know what to do. I don't want to order parts, willy-nilly, just to trouble shoot. Thanks! (I've already learned so much from previous posts!):thumbup: