I recently purchased a 1991 Larson 190 All American with a 4.3L carb Merc. I would like to add an ignition safety switch. There are sevral sources for this component, was wondering if anyone had any suggestions as to a good maker, and could you give me a brief runthrough of how this is wired? If I understand correctly, when the lanyard pulls off the switch, it ground out the power to the coil, correct?