RE: ESC Help please
Using the 40-Amp Pro Switch-mode BEC Brushless Controller
This controller is very simple to use, and for safety, will not arm the motor until the throttle stick has been held in the Idle/Off position for more than 1 second. The controller will indicate the soft cutoff voltage setting every time you plug the battery in by first emitting a low, long tone, to indicate startup. Depending on the selected cutoff voltage (default is 70%), you will then hear the respective number of medium length mid tones to indicate the cell count or a musical tone for the 70% cutoff, helping you to confirm the setting before every flight.
Is your throttle trim at zero? Maybe it is not detecting the Idle/Off.