Overheating 25hp Johnson 1992

[CA Hunter]

New problem!!!
installed a new impeller, new t.stat with all new gaskets..
The motor started on the first crank. Up to 135F it ran smooth with super strong tale tale stream.
[FONT=Verdana, Arial, sans-serif]At 135F the stream became weaker where at 155F it almost completely stopped and the temp were going up rapidly. At 185F i turned the motor off. [/FONT]

I'm sure i installed everything correctly. It is not my first time i install impeller and t.stat.
[FONT=Verdana, Arial, sans-serif]​
Opened the cylinder hear cover and started the motor without it, No water coming from anywhere.[/FONT]

[FONT=Verdana, Arial, sans-serif]disassembled the lower to make sure everything was correct.[/FONT]
[FONT=Verdana, Arial, sans-serif]The impeller is good, the vines are in the right rotation, no slippage, the key is there. The t.stat starts to open approximately at 145F At 155 is is full open.

Any thoughts?[/FONT]

​

[FONT=&quot]
[/FONT]

 

[flyingscott]

Was the water tube lined up correctly those will fall out.

 

[tblshur]

CA try putting water hose on copper water tube with stats out and see if you have flow . hope this helps

 

[CA Hunter]

yes. Everything is lined up. Also, i assembled the lower and started the motor without the cylinder head cover to see the flow. The water was coming out but the flow was not that good. I also checked if the copper pipe is sitting tight. Yes it was tight and no leak from the sides. It just looks like the pump does not crate the sufficient flow.

 

[flyingscott]

Did the old impeller come out in one piece?

 

[CA Hunter]

Yes, and it looked like new.

 

[CA Hunter]

I was thinking and thinking how to insulate the problem if it is the motor or the pump.
The solution is actually pretty simple.

With the lower dissembled i connected a water hose to this copper pipe, secured it in place. Opened little flow of water controlling it by tale tale flow to make it consistent with what i see on a working motor and consider normal flow.
Then i started the motor and ran it for more than an hour.
The temperature never went higher than 136F no matter what i did, it ran on 900RPM for 20 min, than i gave it to run on 2500 for 20, then again 900 and so on.

Now i know, it is the pump. It is on order.
I suspect something with the housing. But who carries? for $25 i'll replace all of it.

 

[CA Hunter]

OK, the new pump arrived and was installed. The motor is peeing like a stallion, the temperature is getting to 143-146F on 900 RPM. As soon as i raise RPM it drops to 135-136. Run it for 40-50 min in the tank. Runs as a champ. Could not be happier for $50 motor with $70-80 parts :lol:

After closer inspection, when i was able to compare two housings, the original was damaged. The metal cap twisted inside and closed the water passage. did not notice it for some reason at the beginning, getting old i guess. Could have saved myself time and frustration, but oh well, it is a learning process.

 

[jasper60103]

Good job. Thanks for the update.