compression reading

[laker925]

What should the compression read on a 1971 mercury outboard 65 hp 4cyl?

 

[rodbolt]

Re: compression reading

within about 10 PSI highest to lowest

 

[laker925]

Re: compression reading

so if they all are arounnd 108 -110 give or take 5 psi that is normal for that motor?<br />I had a 85hp with 125.

 

[Perfidiajoe]

Re: compression reading

All compression gauges will give you a slightly different reading, if they all read about 110 + or - a couple, and you haven't run the motor for a while, that's pretty good. Usually you should do a check warm, with a fully charged battery, & the throtle wide open. Good Luck, Joe