Black exhaust residue at transom waterline

[swcolorado]

My dealer adjusted the carburetor to cure a stalling issue when first shifting into gear. The boat now idles fine but I have a black residue at the transom right at the waterline.

Engine is a 2000 VP 4.3L PEFS. It has other issues (like twice losing power at about 3/4 throttle and not restarting unless I give it full throttle) but I just want to cure the residue issue. VP manual does not show detail of carburetor and how to adjust. It is a Holley 2 barrel.

Any suggestions or links to photos would be appreciated.

 

[Don S]

Re: Black exhaust residue at transom waterline

Choke too tight, or carb mixture too rich.