Flush cooling system 71 25hp Johnson?

[davidmbv]

I’m replacing the thermostat in my 71 Johnson 25hp. Is there anything I should do before changing it? Is flushing out the cooling passages necessary? If so, can you please explain the process?
Thanks in advance for any feedback.
Much appreciated

 

[Sea Rider]

Fresh or salt water use ? Does the motor have a dedicated flushing port in the crankcase ? Flushing the whole crankcase will be good to go for. Remove thermo, bolt cap back on, flush the motor on muffs, barrel for as long as you want, once done remove cap, install new thermo, bolt cap back on and that's it. Can flush with Salt Away using a barrel...

Happy Boating​

 

[davidmbv]

It does not have a flushing port that I know of. It’s only being used in fresh water but I know the previous owner used it in salt occasionally. I’ve owned it less than a year. I will run it in a bucket with the thermostat out then reinstall . Thanks for the response.