OK, so I've just bought an old boat with a 1979 Volvo Penta MD11C engine, rebuilt in 2001 with approx. 250 hours on it when I bought it, and now around 350 hours after bringing her home.
This is my first diesel engine, so as far as the engine is concerned, I'm a complete newb.
Stern was clean when I left, and I had the engine professionally serviced (oil change, oil filter change, all other fluids, fuel filters, and impeller checked, all OK).
Trip was 725 naut. miles, the full length of the Baltic. Sailed about 1/2 of the way and motored the last 1/2 or so when the wind died completely.
The engine performed flawlessly. I ran about 2000 rpm which pushed the boat along at around 5-5.5 knots. Temp remained good entire time. Plenty of water coming out of the exhaust. Nothing to suggest anything amiss.
But upon arrival, the stern exhaust port looks like this (see photo).
So... what's up with my engine? Should the exhaust port be that dirty?