Flyboy...that's what I was talking about, when I mentioned certain O.S. carbs.
If it's running well, I wouldn't mess with it, but if you want to try tweaking it a little, I'd try backing out the regulator screw about 1/4 turn and see if that makes the mid range a little less rich.

boex...I've run them with the pressure line either connected or dis-connected...it didn't seem to make much if any difference?