Help with low compression 4.5 Johnson

[pikefisherman]

This motor has 30 lbs compression It will almost start it will start if I spin the fly wheel.
But on the compresson if I replace the rings, do I also need to check the valve seats and how hard is this to do.If I rember don't I need a tool to compress the rings also.This was a nice running motor I really dont want to mess it all up.

 

[Rick.]

Re: Help with low compression 4.5 Johnson

Is is 30 on each cylinder? I have a hard time believing those numbers as you said it will run. Try a different gauge, and remove both plugs before checking. When you "spin" the flywheel do you do that with a drill or the starter rope. Give us a little history as well. Best of luck. Rick.