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25HP Johnson Water Pumping when cold but not on restart

T

togman

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"I have a 1978 Johnson 25HP th

"I have a 1978 Johnson 25HP that will pump water immediately when it is cold, but when you cut it off for a few minutes & restart it, it will not pump till the engine becomes warmer, then it pumps fine. Any ideas?

Feel free to email me at [email protected] and/or post here. Thanks"
 
"May be a thermostat sticking.

"May be a thermostat sticking. might try with flush tool, running cold and warm make sure is not water pump."
 
"Sounds like the thermostat is

"Sounds like the thermostat is working OK..When it is open, the water pump has to pump a larger volume of water, and this may tale a bit longer..also. the water pump might be showing some wear...I would continue to use it, but continue to watch it..with the motor completely warmed up, should be able to put your hand on the head..will be pretty warm, but not to hot to touch..if it is to hot, water pump time..!"
 
"No, the head is warm, then wh

"No, the head is warm, then when it gets hot, it starts pumping water from the tell-tail hole & more comes out the 2 holes in the back of the leg.

Flush tool, is that like the one that attaches to the garden hose?"
 
"OK, I pulled the water pump &

"OK, I pulled the water pump & all the fins are on the impeller, any other ideas? Bad Thermostat??"
 
"Could be a bad thermostst..al

"Could be a bad thermostst..all the fins on the impeller look pretty warn and bent back..? If so, its pretty well shot....and would result in low volume...."
 
"Yes, all the fins are worn ba

"Yes, all the fins are worn bad & bent back, and there is some scoring inside the water pump housing. The dealer recommended purchasing new housing & stainless base plate along with the impeller.

Think this will cure the sporadic pumping?"
 
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