1980/81 150hp merc water flow issues

spot

Recruit
Joined
Jul 2, 2009
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3
I am having a water flow issue. At an idle I am not getting any water flow out of the "tell tale" At high rpms it will spit out a small amount but not a steady stream. And water will Flow out of one side of the exhaust port but not near the amount on the other. The impeller housing along with the thermostats are all new. I have great water flow coming out of the thermostat housing as well. What is going on, and what should I do? Thanks
 
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spot

Recruit
Joined
Jul 2, 2009
Messages
3
Re: 1980/81 150hp merc water flow issues

Any advice or tips? Thanks
 

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: 1980/81 150hp merc water flow issues

A leaking head gasket or exhaust manifold/gasket can put exhaust gasses in the water jacket and this can lead to cooling issues.

Your motor is old enough that it might be worth pulling the heads for inspection and renewing the head gaskets. The heads should be surfaced/milled flat also to ensure no issues there.

The exhaust baffle or exhaust manifold gaskets may have deteriorated, pull the manifold cover and check the baffle for warpage/perforation. Renew gaskets and torque to specs.

Hopefully this'll help lead you to a solution to your cooling problems. I'm assuming you've renewed or at least checked the poppet relief valves while you were in there?

HTH............ed
 
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