On one of our mower engines, 10.5 HP/Briggs, the key slot on the main shaft is showing major wear. The drive pulley and supporting key are shot, and obviously, I can replace both of them, but what concerns me is the wear on shaft. I know that if the new key and pulley do not fix the problem, then it is likely that the 'play' in the pulley will eventually destroy the engine. I can replace the engine shaft for big bucks, replace the engine for big bucks, or come up with some other strategy. I spoke with a local small engine technician about welding the new key in place. This sounded great to me, but he indicated that the heat would probably be too much for the shaft. He suggested cold-welding with J-B Weld. Have any of you used J-B Weld for this type of application? Thanks!