I am wondering if the problem isn't some factor involving the boat, like
maybe the motor is mounted too high and the pump is sucking air. That could
be a problem when the boat is up on plane, but shouldn't be a problem while
sitting idle.

The pressure is always low. This is either sitting, slow speed or up on the
step. I am still using the boat. (138 hours since it started) There is no
problem if I stay under 4000 RPM. With 50 square miles of manatee zones that is
not a problem.

If that looks good, then the next thing I would try it to connect a hose to
the water tube that goes up into the motor.

I have tried pushing water up the pipe. It seemed to flow pretty good with the
thermostat cover off but I didn't want to build up much pressure and blow a
gasket so I was just going easy with the hose.

I also back flushed it from the thermostat hole down to the pipe. It seemed to
flow OK but I don't really have a reference to how good that is supposed to be.



I suppose the worst thing is that you had some sort of critter get into
the cooling system


My biggest fear is that "critter" is something the first dealer did.

The last words out of his mouth when I left it with him was "if this thing was
running a little hotter it wouldn't make oil" and some mumbled reference to
cutting off an impeller ear. I'm afraid they did something.

The next step is probably pulling the water manifold cover and looking for a
dead rat but that is going to be the dealer, not me.