Not to hijack, but I have a related problem on my I/O.
I have a Chaparral 186SSI with a mercruiser 5.0, after we have been on the water for a while it beeps for about 3-5 seconds, goes off and comes back on a few minutes later. I all guages read good, outdrive lube full, oil full, I change the impeller every year.
It seams to do it more when I come out of throttle back to idle, any ideas??