So, I've been having intermittent issues with being unable to get my engine above 1700 rpm in neutral or in gear. I haven't dealt with this as the issue comes and goes. I'm in the process of doing a bunch of work to the motor so I naturally wanted to check the compression values prior to doing the other stuff (clean carb, replace wet exhaust that is about to burst, installing fresh water cooling system). When I purchased this boat (1976 C&C 33) one and a half years ago, I had a mechanic check the compression. He check it cold and all cylinders were at 110. I think I read somewhere that cold compression checks can result in low readings. So, I bought a compression gauge and did the check. I have: #1=130; #2=120; #3=120; #4=130. Should I be concerned about this? Does this possibly indicate excessive carbon build-up in the cylinders? If so, will this burn off once the motor is operating optimally?
A note on how I did the compression test. Engine warmed up. All plugs removed. Coil lead removed. With the gauge in each cylinder, I had a helper crank the engine in about 3 short bursts (stopping between each burst) until the gauge reached it's maximum reading on each cylinder. The reading would climb progressively with each cranking burst, but after about 3 series of cranks, the gauge would reach a maximum reading after which additional cranking would not result in a higher reading. I don't know if this is how to do it, but I did it this way in an effort to find the maximum compression value for each cylinder.
Any thoughts would be appreciated!
A note on how I did the compression test. Engine warmed up. All plugs removed. Coil lead removed. With the gauge in each cylinder, I had a helper crank the engine in about 3 short bursts (stopping between each burst) until the gauge reached it's maximum reading on each cylinder. The reading would climb progressively with each cranking burst, but after about 3 series of cranks, the gauge would reach a maximum reading after which additional cranking would not result in a higher reading. I don't know if this is how to do it, but I did it this way in an effort to find the maximum compression value for each cylinder.
Any thoughts would be appreciated!
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