[Fuzzdr]

Hello Folks; my wife asked me to inquire about a black superficial film that appears on the gelcoat finish after our Cummins 8.3 engines have been running for awhile. It is absolutely superficial and has not penetrated the surface at all. She is a cleaner and this does bother her. The boat is of the 1997 vintage. Could the engines somehow be out of adjustment causing the diesel fuel mixture to be too rich? Incomplete combustion? What else could be wrong? Or is this normal and to be expected in an older boat?

More importantly what can we do to eliminate or reduce this problem? Any fuel additives that would help?

Any assistance will be greatly appreciated.    Fuzzdr