73 Johnson 135 hp Thermostat replacement

[Paintescape]

Brand new to boating, my boat came with a 73 Johnson 135 hp powershift 2. I am just doing routine maintenance on it and am just starting to learn about this motor.

I am now going to change my thermostat. Any tips or pointers? I was just going to change out the thermostsat/vermatherm, check valve and gasket. Is that it? Am I missing anything?

I was also going to cut a makeshift backplate in the cowl to gain easier access.

thanks in advance for your help.

​​​​​​​Bryan

 

[F_R]

Some won't agree, but I wouldn't mess with it unless it isn't working.

 

[racerone]

There are more important things to check on that motor.----The 1973 models were unique as far as internal powerhead parts go.

 

[Vic.S]

Why are you going to change it ? Motor running too hot or too cold or just money to spend on random parts.

If you think the motor temperature is wrong take the vernatherm out and test it. The centerpin should just start to move at 105° F

 

[Paintescape]

Haha. Well it sounds like you guys are all in the same boat (no pun intended)!!!

But no, no issues "as far as I know". I just barely bought the boat, tried to start it with a bad battery and thought I'd do some maintenance to it (probably some that is unnecessary, but I was trying to get to understand the motor since this is my first boat).

After I drained the oil, I could see water had entered it somewhere due to the foamyness. So I figured I'd do the seals, pump and impeller. And then I figured I'd rebuild the carbs and put in a new fuel pump, hoses and spark plugs since I was already in there ( I know, probably throwing money away....lol).

....And the kicker........ I did all of this, without even ever cranking the motor over myself...so heck yeah, your right, I probably didnt need to do half the stuff I did. I just wanted to make sure I started with a good baseline before I really threw it on the water.

Anyway, it sounds like you all agree that it's not necessary to change out the thermostat until I need too...so I'll hold off and get back to trying to start her up again.

thank you all for your feedback. I appreciate it!!

 

[racerone]

A compression test is the first thing to do.----Did you hear it run ?----Did you test the motor / boat on the river ?

 

[Paintescape]

No, I hate to say it....but it was an impulse buy. I bought the boat and motor and tons of toys and extras for 700.00 so I had to snatch it up. The toys alone are worth that much. The boats exterior is in really, really good condition. Interior, not so much...that will be my project next spring.

But I'll get this baby running by next week...(I hope)

 

[jimmbo]

You could easily get 1/3 to 1/2 of your money back just selling the Cylinder Heads. The 73 135 had the highest compression heads made for the Production 99.6 cu" Blocks. Highly sought after parts by those Hopping up their 90s and 115s

 

[Paintescape]

That would be cool...but I really want to get this going. I think it would be some great entertainment!!