Check the float just like Wenchbender Ret said. If it still hesitates then turn the air mix screw out about 1/2 turn. If that helps you are just a bit lean at idle and a little richer helps the transition. It will not help the gas mileage but it will drive better. If you have one, put a vacuum gauge, on the intake manifold and set the idle with the vacuum gauge. Set to Max vacuum at about 450 RPM. Then watch the vacuum advance and move the throttle a bit. Advance should move. If it does then you should be good to go. If the advance won't move it is not working. Don't plug the vacuum gauge to the line for the vacuum advance it won't tell you what you need at that place. Use the manifold vacuum port where some wiper motors were hooked up. That is not the best place for the wiper motor but I have seen lots hooked to that port.

Steve H