Ah, where to start. I have a Snapper rear engine mower (you know, like the one your grandfather stood up on its end to sharpen the blade) , with the above mentioned B&S Intek engine. About 2 weeks ago, after about 20 minutes of mowing, it just quit. No blubbering, just quit like you pulled the plug wire off. Hit the starter and it fired right back up. For 20 seconds, then it died again. Started again, died again, pushed it in the garage. Decided it must have been a fluke and started mowing again a couple of days ago. Ran 20 minutes, died like first time. Restart, die. Push in garage. Tried googling some answers; most pointed to the fuel pump, but in the Snapper application, gravity is your fuel pump. I also saw mention of the fuel shut off solenoid at the base of the float bowl, so just in case, I removed it and took off the brass "hat" that closes off the fuel supply and re-installed. Start, run briefly, die. Then read that my valves may have tightened up, although, again my spider sense is telling me this electrical. OMG is my exhaust valve tight. I adjust it and it is way harder to pull over using the pull cord just to see how hard it was. Hit the starter and it sprung to life with a much healthier rumble, more like when it was new. Very happy for a minute, then it died again. Now I am thinking it is the coil, which is actually the magneto and coil all in one I guess. I notice that the outer edge of the flywheel has moderate coating of rust on it, as does the business end of the magneto that is excited by the flywheel. I hit both with a light sanding and then wipe down with CRC 5-56. One thing I cannot find online is what the gap should be between the magneto and the flywheel, so I push it to almost touching. Turn the key, it pops once, but won't start. I then put a new spark plug in, won't start. Should I just buy a new magneto ($40 - $50)at this point? What should the gap be between the mag and the flywheel? Any help would be greatly appreciated.