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Cooling system problem on '83 Evinrude 70hp

C

capnlazy

Regular Contributor
I have a 1983 Evinrude 70hp and it starts right up and seems to run good but overheats. I get no water out of the tell-tale. The waterpump was just replaced a couple of months ago and it was pumping good afterwards. I had problems with the stator and replaced it but now it won't pump water. I removed the thermostat housing and fired it up and get exhaust pressure and no water out the thermostat hole. What would cause exhaust pressure to enter the cooling system, bad exhaust manifold? Bad Head Gasket (although I would think if it was that bad it wouldn't even run)? Cracked block? What do the experts think before I start tearing it down?
 
No water in the cylinders. Motor runs fine. It currently doesn't have a thermostat in it. When I removed the cover it didn't have one (which concerns me).
 
Some boaters prefer not to run thermostats, especially in warmer, saltier climates. It can lead to you motor running to cool in colder water. Your motor may also run on the rich side. Although, when running a 2-Stroke, being rich isn't that big a deal normally.

Sounds like you may have blockage somewhere in the cooling system.

I would flush the cooling system and install thermostats since you are in a colder climate. Inspect the hose leading to your pie hole. Also inspect the intake screen on your lower unit. When the screen breaks it can suck in debris that can clog your system.

Hope this helps.
 
I always go for the throat when I have an overheat prob. Even though it was replaced not to long ago I'd start there. New pumps can also break blades or worse.
 
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