Is a black film on top of engine a concern ?

What is your question?

I've have'nt owned my B2300 very long so unfortunately I know nothing of it's history. Odometer shows 223,000 but does'nt work. Changed the oil and held at full level for a solid couple months. Then to my surprise (because it does'nt smoke) the level dropped down 3/4 of a quart over a 2 week period. Can this have anything to do with the black film on top of the engine ,hoses, etc.? I can't touch anything and not have black hands. Where is my oil loss coming from with no leaks ?