Overheating Problems

[bob faulkner]

I have a 1990 Force L Drive 120LD90C. The water pump and impeller were just replaced. The boat starts and idles fine. When in the water it does not overheat at low RPM. If you raise the RPM it will overheat. If you lower the RPM it cools down almost immeadiately. Someone told me the exhaust manifold gasket may be the problem? I am stumped.

 

[jasonbailey]

Re: Overheating Problems

Do a compression check. Could be a blown headgasket.

 

[bob faulkner]

Re: Overheating Problems

I had the compression checked and he said that all cylinders checked OK? The engine sounds great at idle and low RPM? Thank you for your reply.

 

[foose]

Re: Overheating Problems

Originally posted by bob faulkner:<br /> I have a 1990 Force L Drive 120LD90C. The water pump and impeller were just replaced. The boat starts and idles fine. When in the water it does not overheat at low RPM. If you raise the RPM it will overheat. If you lower the RPM it cools down almost immeadiately. Someone told me the exhaust manifold gasket may be the problem? I am stumped.

 

[foose]

Re: Overheating Problems

I think I have the same problem. I built a small test tank and notice when in gear and higher rpm the water flow form my ports is diminished to a small trickle. Someone told me the same think about my exhaust gasket, but I am not sure how that come into the picture. Did you get it resolved?

 

[t.martin]

Re: Overheating Problems

At high rpms the water comes out of the exhaust more than the tell-tale. That is what I was told anyway.

 

[imported_bjs]

Re: Overheating Problems

thats a tuff one maybe impeller is backwards? the exhaust could be plugged up or the intake.i had a problem like this but on a outboard.the exhuast side of the motor was full of sand.i installed a water pressure gauge so i could watch the water pressure.i didnt liketuring around to watch tel tale.