I have a 2002 4 stroke 60 HP Merc.
I took it in for the 500 hr and everything was fine before I took it in. $437
later (a new impeller, plugs and an oil change) I have an overheating problem
when I go over 4000 RPM.
I get Mercury involved and they say go to another dealer. $350 later (lots of
easter egging around, a new thermostat, a housing THEY BROKE and another
impeller) and I am still overheating. I hooked up a guage and it is 4PSI until
the thermostat opens then it is more like 2PSI. RPMs don't seem to change it
much and whenever I get much over 3000 RPM I see the temp climbing. At 4000 it
is very hot and the beeper goes off.
I am collecting a white pasty substance around the thermostat that I think is a
result of evaporating salt water since the flow is so low. Even when it is all
flushed out I am still having the problem.