Hi! I have a Craftsman 22 hp, 42" mower, Model 917.272281. The motor is the 446777-0165-e1. Father-in-law gave it to me used last year, mowed the whole season without issues. Started to use it this spring, and it would only run 30-60 seconds then die. I started looking at it and found a nest behind one of the shrouds, and a plug wire almost gnawed in two. So, there's my prob, I replace the magneto. Still does the same thing. Check the wiring more carefully, and the small wire to the megneto has some insulation missing. I check for continuity, and put heat shrink over the wire. I've checked the switch under the seat, and checked the fuse. I replace the fuel filter and the plugs for good measure, and verify that I'm getting gas to the carb. Still only runs for about 30 - 60 seconds, then dies. Any ideas?