A carb that is runs nice fully warmed up, will need to be held open when cold. Running the screw in to get it warmed up is common procedure.
What we don't know is if this is really the case, and the eddy you had on it was too rich.
However with that cam, its going to want richer carb feeding cold or hot.
This must be because the idle port isn't restricting the fuel. Throttles are still too far open at idle.
That's a logical conclusion. Not really knowing why the old carb did well or what the timing is at raises the question. Timing and fueling go hand in glove.
With no vacuum advance, the 33 at 2000 might be fine. or maybe it could use a little more.
Definately check timing at the low rpms, and also at 3000 rpm. Depending on the springs, it might still advance a few more degrees as the rpms climb. That would be OK.
