If the motor spins at full speed all of the time that usually points towards the speed controller being bad, which is a very common problem. There is a very low chance that it could be a problem with the throttle though. To test which part is bad disconnect the throttle connector from controller and see if the motor still runs at full speed. If the motor runs at full speed with the throttle disconnected from the controller, then the controller is the problem, however if the motor stop running with the throttle disconnected from the controller, then the throttle is the problem.
Here is the Scoot-N-Go wiring diagram:
Please let me know if you have any questions.
The battery pack connects to the speed controller and not the motor. Here is a basic wiring diagram showing which parts connect to the other parts in the circuit. The battery pack usually connects to the speed controllers thick red and black wires and the motor usually connects to the speed controller thick blue and white/yellow wires (although the speed controller's thick motor wires are sometimes different colors).
Please let me know if you have any further questions.