96 Johnson 225 zero compression upper right cylinder

cobbcfi

Petty Officer 2nd Class
Joined
Jun 30, 2010
Messages
150
Having major issues, J225txede engine, engine won't fire.. Did a spark test and bottom left and middle right bank have no spark.. 5 cylinders have compression between 100 and 110, the upper right cylinder has zero... Removed and re-installed the compression tester several times with no luck...

With all spark plugs removed, the engine will only spine about 1 rotation or less on 5 cylinders tested but upper right the engine turns and turns without issues other than the Guage reading zero!!

I know if all cylinders are around 10% of each other regardless of the number range but how the hell am I getting zero on one of them?? Is that a blown gasket or collapsed rings?? I bought the remanned power head about 5 years ago and it's been running great..

Any help would be great!!
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,412
Blown head gasket or major cylinder issues.----You have no choice.---Cylinder head must be removed for a look see.
 

cobbcfi

Petty Officer 2nd Class
Joined
Jun 30, 2010
Messages
150
A blown gasket could bring it all the way down to zero?? Damn... I'll pull the head off and take a peek..
 

cobbcfi

Petty Officer 2nd Class
Joined
Jun 30, 2010
Messages
150
Are these headbolts like a car engine and must be replaced or can they be reused?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,412
The heads will be warped ( they all are ) , refinish them before installing.
 

cobbcfi

Petty Officer 2nd Class
Joined
Jun 30, 2010
Messages
150
Left bank compression is great but I'm checking for warp and replacing the gasket regardless.. The right bank is great minus the top one.. I'll check for warp, if I get the head machined I might as well do both, right??
 
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