Hey Guys...just bought a 81 15 ft Titan Thundercraft with a 75 mercury. Third time out today, was running great, pulling the kids on a tube. As I was idling while the youngsters were climbing back on the tube, she dies and a buzzer goes off. Overheating?? Recently replaced impeller per the last owner. The water was circulating earlier as evidenced by the peehole stream. I've been an I/O man, first outboard. She wouldn't restart, had to be towed. Incidentally, the part of the wiring harness that comes from the ignition switch was very hot. Aleso the motor wouldn't turn over unless I advanced the throttle.... nuetral safety switch issues?? I'm baffled. Any help appreciated.