compression specs

[baja32]

I have a 1980 150 hp merc. -im going to check compression this weekend. What are the specs? Also this is a thirty year old motor that runs and pushes my 20 footer to about 40 mph. With that in mind I don't expect my numbers to be perfect when I check them.

 

[JB]

Re: compression specs

The spec that matters is the span of measurement of all cylinders, baja. They should all be within a 10-15% span.

It is typical to have them all well over 100psi, but there are so many variations in guages, conditions and technique that there is no minimum spec for psi.

I all cylinders compress within 10% of each other you have a healthy engine.

Good luck.