Re: mercury 200 optimax 2002 compression
This is from the OEM service manual.
Engine Compression
Engine compression should be checked with engine block warm, throttle shutter wide open, all spark plugs removed and using a fully charged battery. Normal compression for all cylinders should be 620.5 to 758.4 kPa (90 to 110 psi). Cylinders should not vary more than 103.4 kPa (15 psi) between one another. A variance of more than 15 psi would indicate the need for a power head inspection/disassembly.
