Whats killing my 95 PCM GT 40?

I have a problem with my 95 Ski Nautique. It was 85 degrees out and when attempting to start the boat (for the first time that day) the dash ignition switch push button would not stay in. I lifted the engine box for 15 minutes and then it would stay in until I tried to start the engine, the engine would start, the button would pop out and kill the engine immediately. Eventually it stayed in and running for about a 15 minute boat ride and then the engine died. After a couple of 30 second run/die I got back to the dock. My safety kill switch is bypassed. Something is defiantly killing the engine??

I spoke with the local Nautique dealer and he said to check the voltage at the fuel pumps. If your not getting enough juice it could be electrical short or the fuel relay's are bad. He also said you might want to first check the actual Amps at the dash ignition switch, it should be at 12 Amps with everything on. if the less than 12 amps it could be a bad ignition switch breaker. Please let me know if you hear of any other ideas?
Thanks

Thanks Tim, Have you experienced this with your 90? I'm leaving on a camping trip next month and its on the hot side of our state.

I just ordered a Fuel Sender from SkiDim to replace my factory sender, the current one only reads 1/4 full when the tank is full. I wonder if this problem, is related to my original dieing problem (with the engine cutting off)?