S.U. Carburetor Kick-Down Adjustment
Tony's Tip #4:
One of the most typical problems with the S.U. carb is that users find they need to momentarily depress the accelerator pedal to the floor in order to cause the inertia of the return spring driven mechanism to bring the carb back to its normal idle speed. This action is typically called, "kicking it down." Many suffering with this problem try to fix it by changing return springs, tightening (by turning) throttle shaft springs, lubricating the ball joints, installing new throttle shafts, rebuilding the carbs, and ultimately, buying new carbs. None of those actions will fix the problem. The problem can be fixed by adjusting and tightening the solid inter-linkage shaft. This problem I've suffered with for decades was fixed within minutes by someone who knew how to calibrate the carbs and that person did not even need to rebuild them. Unfortunately, I have not found any written instructions as to the exact procedure to adjust the inter-rod link, nor the other adjustments on the various ball joint connectors on the S.U. carbs, but I was lucky to find someone who was able to make the adjustments despite not having written instructions as to how to make any of the many adjustments on the various linkage shafts and joints. Sure, there are many written instructions on adjusting the carbs themselves, but I haven't seen any addressing the exact procedure of adjusting all the connecting rods and joints. Bottom linen is if your carbs need to be kicked down for the engine to return to idle, the problem may NOT be in the carbs themselves.