What do the plugs look like? They're the best indicator of whether it's lean or rich. My initial thought is the floats are too high or too low, but I wouldn't mess with anything until I knew for sure. You need to verify whether it's a fuel or ignition problem. High secondary resistance in the ignition system will cause hesitation problems. (problems can occur if on the primary side also) Check your car & rotor real good for any signs of burn through. I've seen many rotors burn through & cause the voltage to short right to the distributor shaft. initially the problem will only happen under load.
