1985 mercury 50 4 cyl not peeing at wot

deeps480

Cadet
Joined
May 7, 2016
Messages
19
Replaced water jacket gasket and the water is still hot. I does anyone else have any other ideas what could cause this.

Maybe the water out the tattle tale should be hot because it is coming out of the very top of the block?
 

sutor623

Rear Admiral
Joined
May 23, 2011
Messages
4,087
Dang man you have certainly had a time with this!!!

Here is something that I like to do with my motors before I put waterpumps in.

I will put a water hose (and adapter if necessary) right over the copper water tube and turn the hose on. Then you can see if water is coming back down the side of the water tube (indicating the water tube is not sealed up at the powerhead.)

You could also fire the engine up and see how she cools while running. (Here is where an infrared temp gun comes in handy.) Then you can check with your temp gun all around the block and see if you have any hot spots (170 degrees or more.) If you still cant find the issue you could give it SOME throttle and see if it starts to heat up too much.

REMEMBER: If you start the engine with no gearcase then you have no load on the engine. DO NOT rev it up more than 1500rpms or so.

Anyways, some may disagree with starting the engine with no driveshaft connected, but it has always helped me isolate a water pump issue vs. a blockage in the engine itself.
 
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