Re: Run a commander when there used to be a mercontrol?
That's your kill wire (black/yellow counterpart). When you turn the key to the Off position, the two terminals on the key switch labeled M are connected and the kill wire is grounded (If it's a Mercury switch, it'll be labeled A,B,C,D...I don't know which is which). That stops the spark. I'm thinking that your ignition system has a distributor? In that case the amplifier gets 12v from the ignition switch and the spark is stopped when the switch is turned off by not getting that 12v anymore. If your ignition system has coils for each cylinder, then yes you'll need that wire to kill the spark.<br /><br />There is a kill circuit on the distributor ignitions as well. There is a mercury switch that will kill the ignition if the motor is tilted too far. You could tap into that if you wish, but I wouldn't consider it necessary if you have a distributor.