Today I had some time to start the old 312-8. I charged the battery box, sprayed some carb cleaner into the carb and fired up the engine. It fired right up. I had connected a wire connected to the negative post of the battery. I turned the key off but the motor kept on running. Then I touched the ignition switch and the engine quit. I tried it several more times and each time the engine would stop when the wire contacted to the switch. Does this mean that I need a new switch?