8.1s - what's considered good compression numbers?

R-and-R

Active Member
May 9, 2018
258
Boat Info
Boatless
Engines
Boatless
Just had compression checked while getting some other service done.

2002 with 820 hours.

One engine had numbers between 170-180 on all cylinders.
Other engine had numbers between 175-185 on all cylinders.

My mechanic says those numbers are okay.
Anyone here beg to differ?
 
Looks OK to me too.

In my experience some mechanics do cold comp tests and others do warm…..and they seem to have their own reasons for doing one or the other.

I had mine done last year when my manifolds were changed at circa 700 hours, boat hadn’t been started for some time and cold comp test was high 170s to 190. When I bought the boat 5 years earlier warm was around 200.

Of course compression gauges can vary too.
 

Forum statistics

Threads
112,946
Messages
1,422,789
Members
60,930
Latest member
Ebrown69
Back
Top