PSC31 Engine rebuild
Finally got to examine my removed 3GM30. The problem was a catastrophic failure of the rings on #1 piston. Deduction leads me to conclude that this was directly related to the haul out and the hard start when I picked up the boat to go home. There are stories about tilting the boat too much and getting water into the exhaust manifold. Quite likely that was the problem although I could never prove it because I never saw the lifts. Despite many cautions about babying the engine by running it at too low of a speed for too long, there was absolutely no indication in the cylinders that this was a problem. In fact, except for the scored #1 cylinder, everything was beautiful. I think that kills the myth that running at 2000-2500 for cruising speed is detrimental to the engine. This turned out to be a very expensive haulout, although I don't have the bill yet for the rebuild. On the plus side, I will now have a rebuilt 3GM and don't expect anything other than routine maintenance for a long time.