We (me anyway) would like to see pictures of the
issues with your reversing mechanism rather than
speculate what you may have there. Someone here
should be able to make some sense of it.
I would suspect and be looking for a failure in
one of the insulator’s going to the spark plug
wire, starting here (arrow), with the insulation
on this wire looking for a place where the spark
could be jumping to the mag plate.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.