adjusting a weber

i got a weber for my 2.0 it runs but its shakey and im pretty sure its running rich because there is black stuff coming out of the exhaust and my spark plugs turned black too. the instructions say turn the little black screw in until the idle drops then turn it out till the idle drops then set it half way inbetween those two. but when i turn it in or out nothing happens? do i possibly need different jets? also it has an electric choke and when i wire it up it runs worse so i left it unpluged.

I'm Not Really sure,(I don't have a weber, But want one!) But maybey if you plug it up and then mess with the screws then you might see some diff.

Which Weber do you have? It will be stamped on the bottom of the carburetor base. I have dial in instructions.

not sure i think its the 34something. its the cheapest model. i had the instructions but when i turn that adjustment screw nothing happens. i think it needs different jets or something.