The throttle potentiometer assembly (often referred to as the throttle "pot") includes the potentiometer itself, a plastic paddle and a spring (not seen in picture) to make it spring back to center. The paddle is squeezed/pushed to make the scooter move forward and backwards. Occasionally, due to rough handling, clothing catching on it, etc., the paddle can break off on the left and/or the right side.
Replacing the plastic paddle requires a Philips-head screwdriver and can generally be performed by the customer. The two screws can be accessed by looking beneath the steering tiller and without having to disassemble the control console.