This is my latest development with my 1977 Black Max 175. Starts and runs like a dream. When I go to turn the key off, the engine hesitates and rpm goes down, but it won't kill. Please help. I've removed wiring harness from key and touched wires from engine, and still won't die. There must be something that's not grounded properly, but I can't find what it is. What could this be?