98 GSX compression

[cal31967]

My new-to-me 98 GSX has compression of 150 psi on the PTO cylinder and 180 psi on the MAG cylinder. Any ideas why the MAG is so high?

 

[mikidymac]

I am guessing your gauge isn't accurate as the 951 should only be blowing 130 psi on a perfect engine.

Given that, you have an issue either way because you should never have 30 psi difference in cylinders. More than about 5 psi and you have a mechanical issue like a seizing piston.

 

[cal31967]

I'm starting to wonder about the guage. The initial test showed 120 on the PTO and 180 on the MAG. Either way, something is wrong or the guage has crapped out. I've used it before to test other engines though and there has never been this big of a discrepancy.