switches acting different no clue

Hello,

I am not very clear on wiring and that is why I have come here. I am trying to wire up a momentary switch to a external DC motor. The problem I am having is one switch will work perfectly but the other switch has what looks like a rebound. For example when you go to close the motor it will go all the way closed but when you let off the switch its almost like it lets the motor "relax" which backs the shaft off a little bit.. I know I am rambling so I will wait for some people to chime in and try to answer questions promptly and efficiently.

Thanks in advance.

Hi,
Is the motor a door lock actuator? or a motor with gears, or driving a linkage/mechanism? If there is flex or elasticity anywhere in the system, the mechanism will "push back" once the power is released.
Mark

Its a DC motor with a shaft coming off and we are using it with a butterfly valve to seal a opening. The thing that I don't understand is why one switch will close the valve and keep it closed but the other switch will close then pop back open. The reason I am set on using this one switch is that I have several of these already. If me posting a picture of the motor would help I would gladly do that.