Took her out for another river spin today after adjusting the throttle cable for more top end. Also raised the angle of the outboard 1 pinhole. Noticed some slop in the magneto advance actuator on the throttle linkage, upon disassembly the actuator is missing two plastic bushings. The slop from the missing bushings is preventing the spark advance from returning to zero at idle. This explains the rough idle I noticed while loading today, though it ran great at high rpm for an hour and a half straight. The bushings are no longer available, but I found a used set on ebay. Needs more pull still to get full throttle, I will wait until I have replaced the bushings before I adjust it any more. Today I GPS'd 15 mph upstream and 18 downstream. I should cruise comfortably at 20 mph when adjusted correctly.