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1974 Johnson 85hp cooling issue

M

mvabate

New member
I'm a newbie when it comes to boats and repairing them. I replaced the whole water pump, as my 1st repair and everything worked well. Now I believe I have a clog somewhere after having the boat out and beaching it. I have water leaking between the lower unit and the mid-section. So I pulled the lower unit and put a water hose up both of my tubes. I only get flow out of the rt tube. The left side I don't get any flow. I have the lines disconnected at what i believe is the Tstat. Is there a way of dislodging my clog, or do i have to pull the motor apart. Thanks for any help.
 
You dont state that its getting hot in original post other than its leaking water between mating halfs..is it getting hot?
 
Thanks for the help. I pulled the thermostat off and was finally able to get water to flow through both tubes. Is there a method to testing the thermostat? I never ran the motor without water running to it and I don't believe it ever overheated.
 
Water leaking between the lower unit and the long exhaust housing is normal after installing a water pump UNLESS you apply the sealer mentioned below on top of the lower unit surface. Think about it... that is a metal to metal surface with no gasket.

Bombardier 3M Product #847 (Available at your local dealership, marine stores, etc)

One water tube is the entry tube, the other is a return tube that that recycles the water until the thermostat opens.

Water will flow from the holes/slots just above and to the rear of the cavitation plate ONLY when the thermostat opens.

If the engine isn't overheating.... why are you looking for a overheating problem?
 
Joe Reeves, I'm in the process of rebuilding my carbs due to a hard starting and bogging down at WOT. I fired it up on muffs and it idled at 2500rpm. It ran for about 5min like this. I adjusted my throttle cable and solved that problem. It was after this I noticed the water leaking out of the lower unit. It didn't do this after I rebuilt the water pump. At no time running at 2500rpm did any alarm sound. I was hoping that the leaking water was from when I beached it, not the latter.

I wondered about the no gasket between the lower unit, that and the inlet & outlet tubes makes sense.

After I pulled the Tstat off, I found a small piece of rubber that could of been clogging some flow. Also you stated that water will only flow once the stat opens.
As soon as the motor runs I get water flow.

I put the vernatherm in a pot of water at 140 plus degrees and it doesn't change. I thought it was stuck closed, but from what you are saying maybe its stuck open. Thanks again for all the help!
 
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