Hi, hiker1:
Are you sure you have the correct  throttle/pitch curves?
If you are hovering, set both knobs (hover/trim and pitch) at center point, then try hovering if you notice too much speed in the head, slide the hover trim to next dot clokwise (one position to the right) and keep the pich "cero".
If you steel have the "super 370" on board, this is gona bee the problem. Change to brushless. but if  you have a it already then try all the electronics with a diferent radio set so you really know if you are facing an  electronic trouble or a mechanical one which may be too much tension on the tail or motor too tight to the transmision.
Good luck!