Make sure you dont have a End point adjustment issue. Use the appropriate manual for your radio adjust the End Points to a higher through and see if that fixes your issue.
Also you say the servos are only moving a 1/4'' inch in either direction, Is the control surface moving to the specified control throughs? Im not trying to insult intellegence I just dont know your experience level. You are supposed to make sure control throughs are moving the required distance. This is measured on the control surface (I.E. If its a elevator you measure the trailing edge of the elevator and not the movement of the servo arm. Again you might know this already just wasnt sure.