Compression good or bad

[gustafsonerik]

87 force 85hp the engine was a little hard to start i did a compression test..

cylinder 1 100
cylinder 2 105
cylinder 3 100


is this good or bad??? thanks Erik

 

[shrimpman123]

Re: Compression good or bad

from what ive always been told, its good erik. if all cylinders are 10-15lbs within each other,its good.but maybe some of the pros can tell you better.

 

[Bigprairie1]

Re: Compression good or bad

Those readings indicate the motor is in reasonable balanced condition but down a little overall in compression which means probably down on power somewhat.
Ideally, considering a little general wear, the readings should all be 125 or better.
'New' compression would have them all up near 150psi I believe.
It should run fine with those numbers but you are going to be down in power somewhat and you will be do for a rebuild over the next year or so I think.
My two bits.
BP

 

[JB]

Re: Compression good or bad

Compressions readings vary too much from guage to guage and technique to technique to say those are even a little low, Erik. A different guage used on a warm engine with 5 or more revs per cylinder might give you 150psi across the board.

The purpose of a compression test is to discover any cylinders that have a problem. That is why the 10% span is important. You do not have even one cylinder with a problem.

If you have a hard starting problem it is not related to compression.

Relax and go fishing.