Force 85 overheat at idle

[wurtzelman]

I have a 1985 Force 85 hp outboard. It overheats at idle, but not at higher speeds. The thermostat is good, it opens OK. I just replaced the complete water pump and it is OK.<br />I removed the thermostat and cover. When operating at idle, with earmuffs, no water makes it up to the thermostat housing level. At higher engine speeds, water does come up to the level, but not with much pressure. When I put the thermostat back in and open a plug in the top of the thermostat housing, no water appears at idle, then it does at a higher speed.<br />When I removed the lower unit to change the water pump, the inlet water line, which goes up from the outlet of the water pump through the motor leg, was loose and dropped a few inches. It slid back into place, but I'm wondering if I am losing water at the top of the water line. From the parts list there is supposed to be a waterline grommet and a seal there. <br />I''m wondering if those have failed somehow and water is leaking out there. I don't know if they are. How do I replace them if they are missing? I seem to be getting a lot of water out of the spray holes at the back of the engine, and I have read that there should just be a spray coming out there.<br />Thanks in advance.

 

[bnk999]

Re: Force 85 overheat at idle

On my chrysler the only way to replace those was to remove the powerhead - Probably the same on your motor-

 

[Docdoc]

Re: Force 85 overheat at idle

Did you look at the inside of the water pump housing? If it is badly pitted, then you aren't getting a good seal on the impeller vanes at idle and not moving enough water. When you hit higher speeds, the vanes don't even really contact the walls of the housing, therefore you are moving plenty of water at that time.

 

[scotiany]

Re: Force 85 overheat at idle

You got to remember that at high speed the ram effect of water entering your engine is in effect. The water pump/impeller is most important at low speed/idle. So, I'd look at the impeller. The only way I can think of checking if the grommet is in place is by dropping the motor leg. Did it by myself on my Chrysler and it wasn't hard to do.