502 mag MPI Compression
 

I am looking at a boat with twin 502s. the compression test showed 120 to 125psi. I read on other post that a healthy 502 should be between 150 and 160psi.

are these motors on their last leg?

130-140 is much more realistic.


I'd really want to know if the compression check was being done right. 125 is a touch low.

What philster said. Engine at operating temp, all plugs out, throttle wide open, ect....