Am I the but one? Heh-Heh........
Probly not so here goes;
I assume that you have proved that the bowl is dry in the morning, and are not just guessing. If you are guessing, then I'll be guessing;
Your carb is junk. It has a hole in the bottom, and its not easily repairable.When you take it apart look for the hole.Do not put it back together and hope for the best. Look in the lowest part of the bowl, under the mainjets.
If the engine runs the same,no matter where the mixture screw are set, then the engine is getting its idle fuel supply from somewhere else; perhaps that little hole I spoke of. And/or the low-speed circuit is plugged.
But if you're guessing, I'm a gonna reach through the screen and smack you!
And just why do you want to fix it, if you're just gonna put a 4bbl on it? You lost me.,
