1979 Evinrude 9.9 compresion help

[sirdank]

I have just obtained a 1982 9.9hp rude that runs great, and a 1979 9.9 that doesn't. On the '79 it has sat in a basement for years on its side. There is very little compression if none. We took the head off and the exhaust port and it all looked very clean and no scoring on the walls. The flywheel can be turn very easily by hand with the plugs in. I was thinking about rebuilding in my free time and also about putting the 15hp carb on it. My question(s) is what could be the problem with the compression and would it be worth the 15hp carb?
by the way the rings are free on the pistons.

Thank you

 

[tashasdaddy]

Re: 1979 Evinrude 9.9 compresion help

turn it face down, plug hole up, head up, soak in marvel mystery oil for a week.

 

[Whoopbass]

Re: 1979 Evinrude 9.9 compresion help

Maybe a bad head gasket?
It probably would cost quite a bit to rebuild it and buy a 15 hp carb for it. That carb sells for about $150 on ebay.

 

[JB]

Re: 1979 Evinrude 9.9 compresion help

"There is very little compression if none."

This is not useful. need numbers.

 

[jbjennings]

Re: 1979 Evinrude 9.9 compresion help

when you turn the flywheel by hand, do you see both pistons moving up and down? If so, and the rings are free, I'd think blown head gasket as well. But I'm thinking even with a blown head gasket, it should make some compression.
Something's bad wrong if it turns easy with the plugs in. Usually something obvious. If the pistons aren't moveing up and down--sheared flywheel key or broken rods.
JBJ

 

[sirdank]

Re: 1979 Evinrude 9.9 compresion help

the pistons are moving, and it moves a little air but the flywheel turns very easily(with the plugs in). I will find a guage and get some #'s this week hopefully