Mercruiser 3.0 running fine and dies... then no power

by Dan
(Raleigh, NC)

We have a little 18' SeaRay with a Mercruiser 3.0 that just did something very unusual. This was our first time out for the season. Started fine and ran as usual. After warming up and checking things out, we pulled the kids on tubes for maybe an hour. As we were getting ready to head in, we were running at maybe 1/2 throttle, on smooth water, when the engine suddenly died. Wouldn't crank at all... in fact there was no power to the instrument panel or ignition switch. However, the aux power panel (blower and lights, etc) had power. I checked battery connections, tried a few more times, and then started paddling. After 15-20 minutes I tried again and it cranked fine.

Any ideas? Could something have overheated that would cut all power to the engine until it cooled? Any thoughts would be greatly appreciated!