Like all boat lovers, I spend time during the summer cruising the docks in the summer, and website in the winter. I live in Michigan. One of the things I've noticed while looking at the engines on the "Boat for Sale" website is how nice and clean the engines are. Now I know a person selling their boat is likely to clean the engine compartment, .....but My iron jib, a universal diesel on a 28 ODay, is covered in fine black dust/soot. What could the issue be? What should I look at? I've casually looked at the exhaust. It does not seem to have any location with real heavy concentration of the dust (hole or corrosion). It has the same amount has all the rest of the engine. Is this just "common" for a diesel?