Smell of Diesel fumes in Engine Compartment

[fryewe]

If it were your exhaust, you would have black soot in your boat, especially in the engine room. If your engine room is painted white or off white, it would be obvious on inspection if you have an exhaust leak. Beginning to sound more and more, to me, like you have some insulation or foam that perhaps got wet with fuel, you have a small leak, or you have a fuel injector problem. Also, when the engine is running at higher rpm, the excess fuel that is pumped by the FI pump recycles back to the LP side of the fuel system (engine mounted fuel filter on mine). These lines may be the source of your leak. If you have a leak only at high rpm and it is seeping onto a hot engine surface, it might be evaporating due to the heat. Look for gummy deposits on the head and crankcase.