compression readings...

[svillebrian]

I have a 2001 johnson 90hp 60 degree. I'm getting ready to pull the plugs and check the compression. I think I have a bad head gasket. Does anybody know what the compression would be? Also, if the compression is bad and it is the head gasket as i presume, when i tear it apart, what else should I look for to make sure no other damage or problems have occured with getting water into the cylinders...

 

[Bifflefan]

Re: compression readings...

Compression should be 90 to 120 on all cylinders and not more that 10% difference between them.
As for the what to look for, If the head gasket is blown then there is a reason and you need to find it or it will happen again. Find a friend that has worked on engines of some sort and ask them to look at it and show you what to look for. The basics are the same on all engines.
It would take all day to type out all the things that you could look for.