Blown Cylinders???

[Dobb15]

I am helping a Friend with is 79 searay and it has a 4 cylinder in it ... i compression tested the cylinders cold and the front has 125 the back 90 and zero in the middle 2 ??? could this be a bad head gasket??

 

[Don S]

Re: Blown Cylinders???

It could be, but with 0 psi, I would expect possible head or block errosion to go with a bad gasket.

Was the engine running ok, then just quit, or is this a rebuild not working?