Most ESC have a method to set the endpoints of the ESC
Try that...
Note About ESC's
Some ESC's will not work until you set the Endpoints.
To do this:
REMOVE YOUR PROP (for safety)
Turn on your radio, throttle trim all the way down (leave it there), move the throttle stick to full throttle, plug the battery into the ESC. The motor should NOT spin, the ESC will beep beep (high endpoint learned), move the throttle stick to off, (the low endpoint is now learned). The ESC should now arm normally and be ready to use.
Rebind after doing the procedure so that your radio will learn the correct failsafe positions
The boys did a quick tip on this one a little while ago...