1967 Johnson 9.5 hp

[Mo Tick]

Hey Gurus, i ran this motor and felt where the thermostat is, and it felt hot, running up the RPMS, actually slowed water comming out and at a low RPM, the water was hot...so i shut her down.

i just replaced the impeller and put it backk together, now no matter at what rpm i get good cool water, but the Thermostat housing is still getting hot, hot enough you cant keep your hand on it.

is this normal? or should i knock the duct of the thermostat try it again or just replace it?

thanks

Tom

 

[ezeke]

Re: 1967 Johnson 9.5 hp

Is the water spitting out of the exhaust relief bellows just below the cover all of the time?

If not it should be.

 

[Mo Tick]

Re: 1967 Johnson 9.5 hp

water is comming out of one spot, looking at the motor from the rear towards the front. it comming out of a hole threw the bottom pan where the cowling connects to, a black flex tub is connected to the lower left side of the block. and yes water comes out of there all the time.

 

[ezeke]

Re: 1967 Johnson 9.5 hp

OK, that tells you that your water pump is working.

Now carefully remove that triangular cover and remove the thermostat. Then put the cover back on and run the motor. That should tell us if the cooling circulation works or not.

 

[steelespike]

Re: 1967 Johnson 9.5 hp

Head should be too hot to hold your hand on but not so hot it burns you.

 

[Mo Tick]

Re: 1967 Johnson 9.5 hp

ok, removed the Thermostat, and ran the Motor, you can now touch the head and especially around the thermostat area with your hands and not get burned.. so i guess i'll replace the thermostat. or can it run with out one?

 

[ezeke]

Re: 1967 Johnson 9.5 hp

The thermostat is closed when you start the motor and opens at 145 F. degrees. If you want to be thorough, you will need two melt sticks, a 125 and a 163. The bottom line is that the 163 F. degree melt stick should never melts on this motor.

The 125 should melt when at operating temperature with a properly functioning thermostat

 

[ezeke]

Re: 1967 Johnson 9.5 hp

Sorry, Yes, if the thermostat is old, replace it.

 

[ezeke]

Re: 1967 Johnson 9.5 hp

BTW, I own six of these old beasts and I've learned a little about them, mostly the hard way. I do manage to keep them running really well.

It's easy to jump over the steps, but in the long run, it is worth the time and money to get a model specific service manual for the 9.5.

Decarb annually. The suckers have three rings per piston and they love to stick and drop the compression.
Despite that, they will run fine at 70 over 70.

 

[Mo Tick]

Re: 1967 Johnson 9.5 hp

thanks ezeke, this motor has sat for 20 some years before i got it going. it starts on the first pull.

i think as cheap as a thermostat is, i just as well replace it. at this point id rather not test it to see if its to hot or not. 8 bucks is a cheap solution, if it hot after a new one then im not going to worry about it.

this motor was my Great granpas, has about 100 hours on it, and in great shape. i need to get some new decals for the cowling as i am going to re-paint it. got any ideas where i can get them?

 

[ezeke]

Re: 1967 Johnson 9.5 hp

Someone here recommended the fellow on this link:

"http://cutnupvinyl.com/_wsn/page3.html"

(Copy the link to your browser without the quotation marks).

 

[Joe Reeves]

Re: 1967 Johnson 9.5 hp

(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperture to compensate for the distortion.

With the thermostat removed, the difference in temperture between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.