I would say that Rick is right on given what you've said. Are you turning the key and the starter just spins? Or are you getting a clicking sound? You can get the starter checked at just about any auto parts store or auto electric rebuilder. You could test it like above by just attaching jumper cables and see what happens...What year is your comp? If I remember I'll post some pics of my 89.
Next project is to figure out why I'm getting so much engine noise through the stereo speakers, figure I'll start with replacing the ground connections from the stereo and amp. And after that, I work on rebuilding the wooden framework for the back seat.
By the way, the water test went great yesterday, left work early and got out on the river and she ran great and even restarted after shutting it off. I didn't even worry about it. Would have gone skiing if I could have fit my fat feet into the bindings, got an old ski from an uncle that I thought I would try out and just couldn't get enough lube on my rear foot to make it work...but the kids had a blast tubing.
Greg
1989 Supra Comp TS6M