Evinrude 30 hp compression question

[maineiac5586]

Hi working on a 1988 30 hp evinrude 2 stroke 2 cylinder. I forgot to check compression before removing lower unit. Tested and only getting 75 psi on both cylinders. Is there a difference in results if tested with lower unit removed? I know I could just bolt it back on and try it again but just wondering before going through that. Maybe the driveshaft not being in the crank causes pressure loss through a lower crank seal?? Thanks

 

[maineiac5586]

Nevermind. I put the driveshaft in the crank and tried. Same results. Oh well

 

[racerone]

You have a worn out motor or compression tester that is poor quality.---Simple as that.

 

[tphoyt]

I would try another gauge just to be sure.
Most auto parts will loan them out.
And as you now know it would make no difference with the lower removed.

 

[Crosbyman]

compression PSI is internal to the cyld's with ports closed off ... nothing to do with crank seals or L.U...

has indicated worn out or bad meter ? .... just run it with a good dose of engine cleaner see what happens.

 

[kbait]

Head gasket compromised between cylinders?

 

[saltchuckmatt]

And if above, bore-a-scope through the cylinders or pull heads and resurface them. Easy to do.