85 Johnson 50 running hot

[ttirb]

My 50 hp gets hot when pushed above 50% throttle. New impeller, new thermostat, plugs are correct. Warning buzzer will quit after a minute when it is idled back. What next ?

 

[hoeser]

Re: 85 Johnson 50 running hot

What kind of thermostat did you install and are you sure it is installed correctly? I've heard some of the OMC stats are engineered poorly and lack a small groove to allow water to pass through to heat and open the stats.

If you are sure your stats and impeller are all good, I would wonder if there is an obstruction in the cooling jacket, you may have to pull the head and look.

It's also possible you are getting a false positive. Have you checked the temperature of the head when the alarm goes? I suggest an infrared temp gun.

 

[ttirb]

Re: 85 Johnson 50 running hot

Thermostat is OMC, but I doubt it is the cause since it was doing the same thing before I changed it and I heated the old thermostat and it seemed to open O.K. I will check the temperature but it feels pretty hot. Should the telltale be hot or just warm ?

 

[tashasdaddy]

Re: 85 Johnson 50 running hot

i'm not saying this is your problem, but i just had 2 brand new impellers fail and come a part. one was sierra, the other OEM.