Johnson 140 overheat 2005

[Lesg]

I am new to this forum and need your help;;;;;;;;;
The engine has 218 hours so has been used lightly. It has always been in a spring fed, clear lake. The over heat light came on within a minute after full throttle, but will run all day at 1/3 throttle. The pisser is strong.
I replaced the water impeller ( which looked good ) with no change.
Since the impeller has been replaced with a new upgrade I replaced the water pump housing ( this also looked good ) with no change.
The thermostat opens at 140 degrees in a bowl so it seems OK.
I replaced both temperature sensors - no change.
I checked the water pressure regulater - it looked like new and all areas were clean so I reinstalled it.
The intake screens are clean and all areas I could see, inside the water jacket were like new.

Any suggestions?
The engine does not have a temperature gage so how can I check to see if it is actually getting too hot? Also what is the correct water temp for this engine?
Thanks in advance,

Lesg

 

[Fed]

Re: Johnson 140 overheat 2005

Your desription sounds like a water deflector problem except you also said the water jackets were very clean.
Still my money is on the deflectors swollen & blocking the passages.

 

[Lesg]

Re: Johnson 140 overheat 2005

Thanks Fed, since I have checked or replaced everything else that I know of, this makes sense. Being new, where are these deflectors and what do I need to remove to access them?
I have the complete manual on the motor, unfortunately, it does not show it.

Thanks in advance,
Lesg

 

[Dhadley]

Re: Johnson 140 overheat 2005

That motor is actually a Suzuki. I don't think there are deflectors but have not seen that many too be honest. You might post in the Suzi forum, there are some pretty sharp folks over there.