Im going to check out a boat tomorrow in Fla. I picked up a compression tool (not sure of official name) from advance and plan on checking the compression of the cylinders. Question - what number should I be looking for? Isnt everything over 115 good? And I know they should be no more than 10% apart, right? Anything else?
The engine is a Merc '00 125 Saltwater. Any helpful hints would be greatly appreciated.
I would be looking for anythig over 100PSI
and just make sure they are within 10-15 percent of each other.
unless you have the gauge calibrated, the inexpensive compression gauges are not real accurate.
it could read 110 and it really be 100 or 120.