:welcome: aboard ol joe. Nice to have you join us. I am sorry you didn't get any replies, but honestly this is the very first time I have seen your thread.
Are you talking about the switch at the helm area or at the engine itself? If you can't shut it off at the actual switch, check to see if those wire goes to the coils at the flywheel. If either of them are cut or not connected, the engine will never shut down. Because when you turn off the key at the ignition switch, it shorts those two wire together to short out the primary side of the spark coils. So time to see what's going on under the flywheel or at least check the wires up to that point anyway. One other thing to do if you have a meter, check to make sure your switch is shorting the two M positions at the ignition switch when you turn it to the off position before tearing anything up. Could just be a bad switch. :noidea: