I have a '90 sterndrive that i guess never had a safety kill switch. I purchased one from iboats (universal) and need to know how to wire it. It has 2 terminals to close Ignition (coil) and 2 to close magneto. Im guessing i just disconnect the 'ignition' (purple) wire and run it to one of the coil terminals on the safety switch and then just run a new wire from the other back to ignition? ...leaving the other 2 of the 3 wires on the ignition itself alone. one says ignition, the other solinoid and not sure w/ the 3rd is. is this correct?