Originally Posted by blueboy758
and the engine i have used and pushes a 5.5m rib with 6 divers along very well.
Yep i am sure it does....
We are only trying to help! I am sure you dont want any comebacks from selling an engine with poor compression and passing if off as being 5 years newer than it actually is.
As NOS points out if those compressions are PSI then your rings are shot,
however if they are % then thats not as bad however, assuming that the two good cylinders are 140PSI then the lower one is 125PSI, that could be a sign that one cylinder has run with a partially blocked main jet and scuffed slightly, or a ring is broken. I am afraid a compression result like that doesn't tell you too much, it could run for many many hours like that,
it may even come back to 100% if its a gummy ring, or worst case scenario, if its a broken ring, the ring could exit the exhaust port
and its "Goodnight Vienna"
If I were you I would give it a good run and re test the compressions,Hot and Cold, get the year right, and re-advertise it. It will probably be a good engine for someone.
Good luck with it