Its hard to tell what you would consider not to much force. General it should not move with just your hands if it does it shoudl be very little, you have to use a ratchet or special tool to release it far enough to get the belt off. these are designed to move a lil when the motor is running. Maybe take belt off and then check and see, if it feels loose or able to wiggle it may be bad, also check the beerings in the tensioner to make sure they are good to..