Mark, The accelerator pump only supplies a squirt of fuel as the throttle is opened, to compensate for leaning. It's effect only lasts a second or so. If your acceleration is sluggish after the first second or so you have another problem there. Lack of accel. pump function will cause backfire on accelaration. You should be able to compensate for the long pump plunger by choosing a different hole in the actuator lever or by bending the actuator rod. It's easy to observe accel. pump function by looking in the carb throat. When opening the throttle you should see a strong squirt into each of two primary barrels. If you think the linkage is at fault, disconnect it and operate the plunger by hand. There are check balls that must be properly in place and clean in order for the pump to work. I might have some old parts around that I can compare for you. John Roth