Longtime lurker on the the forums here. I appreciate all of the great information everyone has contributed.
Some background: 1987 Mercruiser 165 (SN B771432) with closed cooling system that was in storage for two years. Engine was winterized properly before storage, and after cleaning up the points it fired up. Changed the oil, plugs, checked compression and everything was normal. A few days ago I started it up and noticed the temp climbing and no water coming out with the exhaust, so i shut it down and confirmed the pump in the outdrive was not working. I hooked my garden hose straight to the heat exchanger and put the outdrive down into a large tank of water and everything ran fine (idle was a little shaky, but I figured a tuneup would solve that), stable temperature, no unusual sounds.
Today I removed the spark plugs so i could confirm that I had the spark plug wires in the right order before I start doing a tuneup and I noticed water spraying out the the spark plug socket of cylinder 4 when I turned it over. I take off the valve cover and see that my new oil is now white. I checked the compression again and it was normal (150). After leaving it out in the sun for a few hours while I contemplated this new problem, I came back and turned it over again; this time no water sprayed from the cylinder.
Where do I go from here?
