I'm have a weird problem with my Workmaster 60. The engine dies when the clutch is released and the range selector is in neutral. I can start it in neutral and it will run with the clutch depressed but if I don't shift to lo or hi in about three seconds the tractor shuts off. If I hold the clutch down it will continue run in hi, lo or neutral. I have replaced the range switch and clutch switch. Any suggestions before I tow it to the dealer.