I have a '94 rage with the 90hp OMC engine. My girlfriend started the
engine at the dock and reved it up in neutral, which as you know can divert
some of the thrust down to the bottom. It kicked up a lot of sand and
gravel, some of which might have gotten into the cooling passages. The
overheat alarm goes off after the engine is used a while. I narrowed down
the problem by checking the heads with my hand and unplugging the integrated
sensor located in the middle of each head. I then disconnected all the
hoses I could to try and see where the water was flowing/not flowing, and
blew into them to try and dislodge any small stones. It didn't help much.
My next step is to try and reach the water hose at the bottom of each head
and see what the flow is there, then use a water hose to try and
power-backflush each hose I can reach. If that fails, I guess I'll get a
book and see about taking off the head on the bad(starboard) side. I
noticed that there is a "plate" around the plugs that looks like it can be
removed without taking off the heads. Maybe that would reveal the water
jacket of the head? Another question is where the thermostat is on that
powerhead? I didn't see it on the top of the heads anywhere.

"Chris S." wrote in message
om...
I just boat a '95 rage with 115HP in good shape last month. We've had
two outtings of a 2 to 3 hours and the boat has shut down both times.
The RPMs dropped to about 2000 from 4500 when at full throttle before
the engine shut off and wouldn't restart until it cooled off. The
overheat alarm didn't sound, but the second time I noticed that the
thermostat was almost 220 degrees.

Any suggestions on what I should look into?