I doubt such a blockage can occur in the less than 50 engine hours I have put on. In fact I was checking my log the other day and found that I was still short of 50 hours for giving the boat an oil change. I am going to change the oil anyway as I suspect quite a bit of unused fuel went into the system.

I have only had the boat for 2 and a half years, and during that time the engine has started and run like a fine watch.

I may have been underpowered for quite some time though. I can only get the boat to go to about 5.2 knots under engine, while I can take it easily a knot faster under sail to about 6.3 knots. Once I get all the fittings and exhaust system tightened up and cleaned up (later this week or weekend) I'll go for a speed run and see if there is any improvement in speed while underway. Gee, it might be nice to motor along at 6 knots, eh?

I do know that I had one habit that may have contributed to this problem greatly. Before I had checked out the AC power system on board, and installed a battery charger, I went down to the boat about once a week and idled the engine to charge the batteries. Did that for about a year. I understand that just idling a diesel engine is a bad thing... they like to be run hard from what I understand.

On the day the engine died, it started and idled just fine, just before it quit. And it ran hard just fine right out past the breakwater before I shut it off. There may have been slightly less power, but I attributed that to some incoming breaking waves at the opening of the breakwater.

It has always been an easy start engine.

There was perhaps one sign... but I didn't notice it until I opened up the engine cover. (my whole cockpit deck opens up for access to engine, water heater and shaft). I noticed black soot on the elbow and on the engine cover just over the elbow. Apparently what had happened is when the blockage became severe, the engine exhaust managed to leak past the one of the exhaust connections just below the elbow. So increased soot was about the only indicator.