2002 merury optimax 150hp overheating

[scozzens]

I have a 2002 merury optimax 150hp with 300 hours. I am having an overheat problem only between 1200 and 2800 rpms. The heat alarm goes off and cuts the power to the engine. water flow seems fine. Above 3000 rpms temp drops to 100 degrees, at 1000 its 160. I replaced the water pump last year. Looking for ideas on what it might be. thank you for any help.

 

[hkeiner]

Re: 2002 merury optimax 150hp overheating

It is easier to diagnose this type problem if you hook up a water pressure gauge to the motor and monitor what happens at various RPMs. However, even if you don't have a pressure gauge, the below troubleshooting guide may give you a clue as to what problems are possible. Others on this forum may be able to provide more specific advice as to your particular problem and a solution, based only upon the symptoms your have already described. Good luck.