I have been struggling with one aspect of my engine, been told many things about compression, can't seem to find what I'm looking for, Question is! what should I expect to see range wise on my engine per cyl for compression? taking into consideration age and average usage on motor, It is a Johnson 225 1999 ocean pro can't speak to the history of run time and how she was run, I seem to have between 85-90 on all 6 cyl, some have stated it's the eveness that is important not so much the value, I've been told 85 was low, that I should be in the 135 range..but was also told by a long time friend and omc mech that omc loop charged engines were low compression motors and 80 to 90 was normal 75 to 79 was low but runable anything lower was a tired motor. my check was done @ after a 2 min warm up, then throttle wide open during cranking, I have no performance issues at the moment, she has more power then boat needs. but would like to get a grip on where I stand on with my compression, been seeing alot of Craigslist adds for v6 motors in the late 90's(96,97,98 & early 2000's) stating great compression 130-140, which leads me that something is ary! asked my mech buddy he says they are wrong that 130-140 on non rebuilt loop charged motors of that year range was impossible and they did not come from the factory with that kind of compression! so trying to determine if I need to expect a rebuilt in the next year or 2 or not
