OK, I will assume you mean the switch box is bad. Look on the crowleymarine web site parts list for your exact motor's switchbox part number and google it. CDI should have one. If you have a distributor, a switchbox from any 4/6 cylinder Merc with distributor ignition made from 1973 until 1979 should fit. You might run the troubleshooting test on the CDI Electronics web site, as it will check the switchbox and wiring. Without running that test there is no way to tell if the trigger or switchbox or both are bad.