1999 Mercruiser Alpha One 3.0L - compression readings

[simon_canada]

Just had a compression test done on a boat I am looking at with an inboard 1999 Mercruiser Alpha One 3.0L .

All cylinders came back at 169 or 170 psi.

From my research, I have had trouble finding whether the PSI readings are within the acceptable range.

I know about the 10-15% rules, but from a spec perspective, I was expecting to see somewhere between 120-140.


Any help/guidance would be appreciated!!

Thanks,

Simon

 

[fat fanny]

Re: 1999 Mercruiser Alpha One 3.0L - compression readings

I have had to do that test @ least 3 times this year (head gasket ) and my readings are in the area of 150 and no higher all cylinders were within 4 psi those readings seem kinda high?

 

[cr2k]

Re: 1999 Mercruiser Alpha One 3.0L - compression readings

Have you tried any other compression gauges? could just be the gauge is reading high.

 

[simon_canada]

Re: 1999 Mercruiser Alpha One 3.0L - compression readings

After speaking with the mechanics at the local marina, the range is quite wide, but they said 160-170 was what they saw most frequently on well tuned engines of this age.