Cooling problem

Ed Brocksmith

Recruit
Joined
Jun 10, 2011
Messages
5
I have a 1967, 40 HP Evinrude electric shift with a cooling problem. I replaced the water pump and thermostat but water still is not circulating. The powerhead gets very hot. It seems that exhaust is coming from out of the thermostat housing tube. There is a lot of blow by when thermostat is removed and the cover is off.

Could I have a blown head gasket that is preventing water circulation?

Ed
 

LongLine

Chief Petty Officer
Joined
Nov 2, 2008
Messages
494
Sounds like some cooling passages around the cylinders are plugged up
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
So.....what have you removed from the thermostat area? If you removed the black plastic housing and check valve & spring below it, you opened up a direct air path between there and the water pump inlet. That lets the pump suck air instead of water.

It is designed to run with all that stuff in place and the cover on.
 

Big Fish Billy

Petty Officer 1st Class
Joined
Dec 31, 2009
Messages
301
While you have the thermostat out, heat some water on the stove and see that it opens at the right temp....if the wife lets you play with boat stuff in the kitchen...
 

LongLine

Chief Petty Officer
Joined
Nov 2, 2008
Messages
494
Check whatever connects the water pump to the block. I had an old engine that had a copper tube connecting the two. The tube wasn't seated properly in the block connection. whoops....

Tom B.
(LongLine)
 

Ed Brocksmith

Recruit
Joined
Jun 10, 2011
Messages
5
Thanks for the ideas.

Compression is 100 on both cylinders. I think my next step is a complete new water pump housing.
 
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