cepx111 hit the nail on the head.
And when he says make small adjustments, he means SMALL ADJUSTMENTS.
If you can feel that screwdriver move in the least, tighten up the set screw to lock the spring and go try it.
Quads are great carbs when tuned right.
How wild is the motor, and what secondary metering rods and hangers do you have on it? The hanger should be a single 'letter' while the metering rods will be two 'letters'.