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Help!! 78 35hp johnson 35853R

Z

zimm1150

Member
I've gone through the motor top to bottom. Original lower maybe bad not sure.
I bought a lower of a 1976 35hp johnson 35603G ( it has the metal aluminum waterpump housing and thin impeller and the mushroom shape key)

New pump and Impeller. It pumps water when cranking and briefly for about 15 to 20 seconds when running, then it stop. After that I get bubble in front of lower coming out.

I've taken and checked this and lost count. I also tried a regular waterpump like that fits my 35603G the taller one, but it didn't do anything. Not sure why same th8ng but talker idk.
 
Did you make sure the copper pipe was in the rubber grommet up top? And is the rubber grommet in good condition? I’m changing mine right now and can’t get the exhaust tube to fit in. So it won’t slide together all the way.
 
Year pretty sure, I put it in first the copper in end bottom, that way I can see it.
Got one more thing to try and that's changing the metal plate out on water pump, have a couple I'll try the one with a bigger slot
 
I said exhaust tube but it’s the tube to keep the exhaust away from the shaft.

I took my motor off the boat put it on its front or the transom mount whatever you want to call it and put the copper tube on the engine side then slid the lower on till I could only get a couple screw drivers in there to get the tube aligned on the pump. But now with it sitting on it’s front the tube that goes over the shaft is wanting to drop down and not line up.

You should put the lower in a bucket and run the shaft with an electric drill maybe. See if you get flow that way and also any pressure.
 
1976 was the first year for that motor and had cooling problems with that gearcase, undersize intake holes or other related problems. Not sure if there was a waterpump upgrade or some other kit that was available. It was 50 years ago and I was 16 working at the Evinrude dealer. Racer probably remembers what the fix was. I just remember they changed the gearcase intake design in 1977.
 
I think there was a upgraded housing with metal tub like the rest. This thing is the original I think with thin impeller and mushroom shaped key. I tried a pump for my 78 35hp but trimmed the impeller ends off a little, didn't work.
 
Raised another two inches, trying to start it pumps, when ot starts and idles it pumps for 19 or 15 seconds then still quits. I'm going to try and find out how long the brass tube is suppose to be. I'm wondering if may e the shorter pump there is a difference in length, doubt it.
Just took off lower again to switch out the metal plate to one that has a bigger half moon opening, the brass tube stayed in when I pulled lower, so guess that's telling me top rubber still good?
Wondering if when that thinner impeller speeds up when ot starts that maybe to soft or flimsy?
 
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