There should be NO relative movement between the gear and the shaft. If one or both of the holes is worn egg-shaped just drill them out to a slightly larger size and install either a spring pin or a solid one, peened on the ends to eliminate any slack. While the gear is off, go ahead and do a detailed cleanup of the centrifugal advance, lightly lubricate it with some high temperature grease like Lubri-Plate, and reassemble.
Important! Grind the ends of the pin flush with the gear before trying to remove it. The peened section of the pin can crack the gear as it passes through the flange unless the expanded part is ground away.
Jerry
