I had similar issue and ended up changing whole thing out similar to MBrannon. In the end I still had issues with the old wire going down to starter solenoid. I ended up placing a ford solenoid set-up in and running it down to the starter. My starter wasn't getting enough voltage to kick over, especially if it was hot. There is a thread somewhere of how to do this. -My be the clicky clicky n start thing Matt was saying to look up. If not search Ford solenoid a few years back.

1990 Black Monty LS Over 300K' 1993 Isuzu Rodeo LS 4x4 46k (yes only 46K!)1989 Honda Transalp 600 Africa twin,