115 Johnson overheat problem

M

mrrstudly

Recruit
Joined
Nov 25, 2009
Messages
1
I've got new headgaskets/deflectors/impeller/thermostats. When I first
started it it overheated. I removed the hose going from the thermostat
to the head and the temp came down. Let it set over night and it did
the same thing. Yes it was on the hose but the other motor did'nt do it.
I'm told it what is called hydro lock, but this is ridiculous. Don't want to
remove the thermostats. Any help?
 
E

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 115 Johnson overheat problem

You did not mention what year this engine is. There is some restriction in the thermostat housing, preventing water from exiting the powerhead. If it's a crossflow 1977 or later, you should check the valve body in the stat housing. There is a pinhole(s) in it which can get plugged with debris. That pinhole(s) needs to be open or the engine will overheat at idle.
 
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