1977 johnson 25hp

[brycebell]

Hey guys, I just completed my rebuild on my 1977 johnson 25 hp. I ran it for the first time today and was just wondering if I could get some opinions on how it sounds. the video it fairly short but any help is appreciated.

I got the cylinders bored out and new oversized pistons put in. All new seals everywhere and everything cleaned up. My concern is that there was water coming out of the exhaust port.

Thanks guys.

https://vimeo.com/40419207

 

[brycebell]

Re: 1977 johnson 25hp

So I took my thermostat out and it appears to be siezed open. Is there any way of fixing this?

 

[Daviet]

Re: 1977 johnson 25hp

Congradulations on the rebuild.
If the thermostat is stuck open, replace it.
You are supposed to have water coming out of the exhaust port in the midsection.
It looks like you need more water in your tub, the level should be above the water pump in the lower unit.

 

[brycebell]

Re: 1977 johnson 25hp

Is the thermostat something easy to find or will I have to order it online?

 

[Daviet]

Re: 1977 johnson 25hp

It should be availabe from any dealer. Do you have a NAPA store near, they carry an aftermarket brand called SIERRA and might be able to get for you.
What is your model number?

 

[boobie]

Re: 1977 johnson 25hp

Needs to be in a deeper and bigger tub.

 

[brycebell]

Re: 1977 johnson 25hp

Okay thanks guys, I will make sure to use a bigger bucket next time and put in in deeper.

Here is a pic of the thermometer, pretty sure it is seized but thought i might as well post a picture just to make sure.

The model number of the motor is 25rl77h

 

[Bosunsmate]

Re: 1977 johnson 25hp

Yep thats stuck open,it should be seating back in the top rim. I think there may be a separate part, a rubber for the thermostat to seal in the housing so check for that when reordering. If there was a big spring holding that thermostat in place there will be a metal cover to go outside the seal too.
I just had a look there seems to be no spring on your model

Its this part- gasket for thermostat
18-0182-9

 

[Rudemen]

Re: 1977 johnson 25hp

Make sure you do a proper break-in on that rebuild, should be in the service manual on proper Break-in procedure. It sounds really nice

 

[brycebell]

Re: 1977 johnson 25hp

Thanks guys,

So I bought a new thermostat, tested it and installed it in the motor.

My next question is about the break in. In my manual it just talks about 20 hours varying the speed every so often. I have been looking around the internet and have come across various webpages describing their procedures:
http://www.sacoriver.net/~red/breakin.html
What do you guys think is the best way to break in the motor? And would I need to add a little more oil for the break in? and would it matter it if it synthetic?

Thank you.