The "without welding" stipulation throws a wrench to most proposals but you might check to see if the hole in the lever on the carb could be moved closer to the throttle shaft without causing the vertical accelerator rod to bind against something. The rod from the pedal to the bell crank on the pin in the side of the block could possibly have the hole on the PEDAL link moved closer to center. Again trial and error to check for clashes or binding.


Evan