91 200hp Merc 2.5l offshore overheating

IBwhalen

Recruit
Joined
Jul 17, 2004
Messages
1
:confused: Symptoms:<br />- at idle/low rpm, temp guage goes to max, pressure guage shows low water pressure<br />- at high rpm, temperature lowers to high end of safe operating range (according to guage) and pressure guage reaads about half of the other identical engine<br /><br />I've just done the folllowing maintenance:<br />- put new thermostats and new water pummp in recently on both motors(which was done to fix this problem)<br /><br />Could it be something else problem causing this? What's the best/easiest way to diagnose this situation?<br /><br />BTW: Anyone know where I can inexpensively get an owners manaul for these engines? What I'm really looking for is a good troubleshooting guide.
 

KCLOST

Commander
Joined
Jun 22, 2002
Messages
2,095
Re: 91 200hp Merc 2.5l offshore overheating

You haven't run the engine without water have you?<br /><br />Is the problem still occuring after the water pump/stat replacement...?<br /><br />Have you looked at the poppet (pressure relief) valve.?<br /><br />If it's stuck open it could cause overheat at lower rpms.
 
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