You will have to make the plug wires. You need solid core plug wire. A chain auto parts stores might have it but most don’t carry it any longer. There is a link below to who I buy from. You need to buy enough for both wires and then reuse the spark plug ends. Also search for condenser # DR70T. It has the correct value for your magneto. Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.