Help black soot in prop exhaust 72' gm 250ci L6

[Captkyle]

Ok so I have. 1972 gm250ci L6 mercruiser mc1
ues I know it's almost 50 years old. Motor starts up fine but seem to be having some odd soot coming out of prop exhaust when on muffs. I just rebuilt the carb and currently have 60% Lucas oil additive to 40% straight 30w. I'm also getting some white smoke out of my vented oil fill cap. Check out the pictures. Some pictures are old please any info would help. Boat sat for maaaany years.

 

[Bondo]

Motor starts up fine but seem to be having some odd soot coming out of prop exhaust when on muffs. I just rebuilt the carb

Ayuh,..... Welcome Aboard,....... My guess is, ya got the float set too high, 'n it's runnin' super Rich,.....

 

[Captkyle]

I have the float set to 5/8" and 1-7/8" in the drop postion. This is using the brass float. These specs are per gm