1977 Johnson 115 water pump

T

TOMCAT1234

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Joined
Jun 7, 2010
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2
I have a 1977 Johnson 115 that will not pump water on startup. You have to open it up wide open in nuetral a few times and it starts to pump fine. It will pump solid until you turn it off, and you repeat the ritual. I thought the pump may be bad, so we replaced the pump, added guide tubes to make sure the water pipes were in the holes, and it still does the same thing.
Once you get it pumping it pumps great and I can run up river for as long as I want, until you kill it. It is a pain running trot lines and having to do that at every line though.
Thanks for any help.
 
kenmyfam

kenmyfam

Supreme Mariner
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Aug 10, 2006
Messages
14,398
Re: 1977 Johnson 115 water pump

Fresh or salt water motor ???
Check thermostats and flush / clean the entire cooling system.
Welcome to iboats.
 
E

ezeke

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Sep 19, 2003
Messages
12,532
Re: 1977 Johnson 115 water pump

Did you add a tell-tale, or how can you tell when it is pumping and not? Is it overheating?
 
T

TOMCAT1234

Recruit
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Jun 7, 2010
Messages
2
Re: 1977 Johnson 115 water pump

Fresh and Salt Water.
Will check into the thermostat.


Not pumping when no water is coming out of rear holes right?
It will over heat if you just take off and do not rib the engine up to get the water going.

Thanks for the input guys.
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: 1977 Johnson 115 water pump

The exhaust relief helps to regulate the back pressure on the motor. It generally would have more flow at higher RPM and flow is changed when the thermostat opens and closes. In any event, you would not get any flow until the mid section fills.

I used the series of motors of which yours is a part for many, many years and they never produce a flow of water out of the exhaust relief until the thermostats opened, until then it was just a little spitting. They never overheated.

You might want to consider installing a tell-tale so that you can tell what is really going on with the water pump. http://forums.iboats.com/showthread.php?t=222677
 
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