Hi all. Appreciate any help. I bought a used boat with a 2020 Honda 20hp outboard. Boat ran fine, had all oils and filter changed and after about 5 hours of use engine oil was jet black.

Additionally there is a thick black residue on the bottom engine holes and the top rear exhaust that comes out.

Upon looking at the oil today I noticed it was slightly overfilled but I changed it and put in right levels.

Why was oil so black? What is that residue? Should I be concerned a deeper issue is looming?

I greatly appreciate help from anyone who is mechanically inclined. I am not. Thank you in advance and happy boating.

I wiped away most of residue but you can see it here. It was on both sides.