I purchased a small 2001 flats boat with a 2001 90hp mercury salt edition. It runs great on the water and has recently had a full service in March.
I’m not a boat mechanic. However, considering the age of the motor, I recorded a compression reading of 74, 74, and 71. My process was to pull the kill switch and test each chamber, pulling out one spark plug at a time.
I don’t know the hours, however can I assume that if three chambers of a new engine are to test in the 100s that this engine to test in the mid 70’s (within 10% of each other) Is just normal wear on an 18 year old engine?
Hope this makes sense,
Roy