" Yes, you can add one. You ne
" Yes, you can add one. You need to just find the right switch. The way to do it is route ground to a specific circuit that is used to kill the ignition. The key switch, mercury switch, and kill switch are all on the same circuit. By looking under the cowel of your outboard, you should be able to find a black wire that goes to each switch box (black boxes). This wire will also be intersected by a wire coming from a small blackish gadget (mercury switch).. be sure it's the right wire - when the ignition is on it will have no continuity, when off, it will be grounded. Somewhere between the engine & control box you need to install the switch on that ciruit so that it routes ground to kill the engine.
Jon "