Sorry -- here's more info:

It's a 2001 4 stroke probably under 100 hours. No digital gauges just a tach, speedometer, and water pressure and all read normal. They have already replaced the impeller, the computer (brain box), and the forward-reverse safety switch, all at different times. When it dies, the motor shuts off completely (no clicks or alarms). When you try to restart, the alarm goes off. The engine will turn over, but will not fire. After about 30-40 minutes, it will restart and run for about 15 seconds, then dies again for the next 30-40 minutes, etc. By the time we get to the dealer everything is working fine, and their computer registers no problems. It happens at various speeds -- wide-open, trolling, half throttle, no real pattern. It has been tested more extensively on the muffs, but has also been tested on the water for several days. The problem is that it is sporadic and unpredictable. Thanks for replying -- really hope you can help me out.