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Hey Mike,

Here's the original THREAD

Did some additional research and verified that because it's a 2 stroke, the throttle does not need to be wide open, compression numbers are the same either way.

Also found out if the engine is an OMC V4 or V6 looper (+/- 80's era) that the overall compression numbers are low normally, around 90 PSI whereas other engines are higher.

And readout numbers can vary significantly depending on the tester gauge used, which isn't a big deal if you get all higher numbers, but if they're all low it may merit checking with a different gauge before drawing any conclusions.

As far as testing an engine warm or cold, the concensus appeared to be that testing a cold engine was fine. Warm engines may give you different overall numbers, but you don't want to see variations of more than 5-10% between cylinders and that's going to be the same regardless of whether the engine is warm or cold.

And finally, how the engine runs when started cold can yield clues to the overall condition (Eg. Hard starting and low overall cold compression numbers don't bode well). Hope that helps some...