ORIGINAL: RAMMJETT
ON THE BUTTERFLY CARB SOME TIMES THE THROTTLE SHAFT WILL MOVE FROM SIDE TO SIDE CAUSING ERATIC IDLE DONT MATER HOW GOOD THE SERVO OR INSTALL IS.THE IDLE STOP JUST HOLDS THE SHAFT STILL .THE BIGGER CARBS HAVE A PLATE ON ONE SIDE OF THE CARB TO PREVENT THIS PROBLEM.I ONLY KNOW THIS BECAUSE MINE WOULD SURGE WHEN I CHOPED THROTTLE QUICK AND IF I TOUCHED THE THROTTLE SHAFT WHEN IDLEING.I COULD CHANGE THE IDLE. WHEN I LOOKED MORE CLOSELY I COULD ACTUALY SEE THE SHAFT MOVE FROM SIDE TO SIDE.I NOW RUN THROTTLE STOP&ELECTRIC KILL
please stop shouting, thanks....
Good info - and points out something that can happen easily. Folks sometimes *remove* the spring that is mounted on the throttle shaft. Doing so permits the shaft with the butterfly to start moving side to side as it rotates open to closed. In very short order, that sideways play will wear the butterfly plate, and then there are all sorts of problems that crop up.
I've always suggested that folks not remove the spring, but just trim off the hook end that is grabbing the throttle stop plate.
If the spring is missing, I'd suggest removing the throttle arm, then getting a suitable compression type spring to mount between the throttle arm and the carb body. That will at least keep some tension on the butterfly.