Changed Thermostat and Impeller, but...

kennygeorge

Recruit
Joined
May 4, 2019
Messages
1
I guess I should have done one at a time and tested, but I wanted to get a "new-to-me" 1973 65hp 3-cylinder Johnson ready for the lake. I changed the starter motor, solenoid, impeller and thermostat. The old thermostat was frozen open with a small opening, so I knew I was on the right track.
I have now run it in a barrel of water, that never got hot, for 15 minutes. No water ever came out of the pee holes.
I'm puzzled as to what is wrong:
  1. Did I install the impeller wrong?
  2. Is the thermostat bad?
  3. Did I not run it long enough? (but I don't want to warp the heads with heat)
After cutting it off, I did see water coming out of the small hole just above the waterline on the front of the shaft housing... Maybe an anti-freeze hole to let all the water out.
I've attached pictures of the old thermostat showing the opening, the installation of the new thermostat and the impeller installation. I used hose clamps to get the impeller small enough to go into the housing and had the blades go the same direction as my engine manual. I did make sure the woodruff key was installed correctly and the impeller was spinning when I turned the shaft by hand.
 

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F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,224
It must be working if you ran it for 15 minutes without burning it up. There is no "pee" holes on that motor. Just the exhaust relief holes in the back that water should mist out. I suggest you get it out of that barrel and onto a boat on the lake where it was designed to run, and see if it is cooling or not. And please don't run it 15 minutes if it isn't
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Did you installed just the impeller or the complete water pump kit ? Pic 1 shows a shot liner that will surely not pump right or will screw the new impeller very fast...

Happy Boating
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,905
SEA....That's a all aluminum housing with no liner....many in worse shape out there still pumping just fine.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,829
Looks like you need to replace / refinish pump housing.----Water does NOT stream out those 2 holes at idle.----It just mists out of them.
 

RBoyd1971

Petty Officer 2nd Class
Joined
Oct 20, 2020
Messages
165
A good bit of water will come out of those holes when running fast and up on plane. Goes from a mist to a steady stream. Doesn't shoot out, just flows or blubbers out. I've had a couple of those motors.
 
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