I have a Smithco Super Rake I use to break up baseball fields. It has a 16 HP B&S Vanguard V twin. It sat for a couple years and was donated to our high school baseball team. It doesn't have full power and it won't shut off. I replaced the ignition switch and it didn't help. I put a wire from the stop switch terminal to the ground on the battery and it still wouldn't shut off. Do you think the coil, ignition module, magnatron or whatever it's called is bad? The carb has been worked on and it is clean.