Black smoke from a diesel engine
, truck or boat is unburnt fuel, usually the injector pump
has been 'opened' up to give more power and it's totally unnecessary if the engine
is 'set up' correctly (i.e timing, valve clearances,etc) and simply a waste of fuel ! Diesel fuel doesn't evaporate. If you have a diesel smell in the bilge, check there's no leaks
and the breather pipe is high enough to the overboard
vent, if not re-route it. Put a good squirt of washing up liquid in your bilges, leave for a day or two to slosh around and clean your bilges & break up the oil molecules before pumping out, do this as a matter of routine after each bilge pump
out and you'll have no smell.