Take it to another shop. If for instance the neutral safety switch wire is open, run a new individual wire. When you have a short the circuit will blow the fuse. When you have an open circuit you have nothing. Each wire that is suspect can be tested with an ohm meter. It is very possible you have a corroded plug connector between the control and the ignition switch. Seen several boats that have been around salt water have these issues. Just looked and both types of controls have plug connectors for the neutral safety switch and all other wiring.
Edited by gary purdy (05/12/16 06:37 AM)
“The world will not be destroyed by those who do evil, but by those who watch them without doing anything” GOD IS GOOD