I have a Futaba S-34 servo on the rudder of my chipmunk that was built and flown before I bought it. Here's the problem: If I apply rudder then let go the rudder goes over center the other direction then returns to neutral and holds it's position. But it still has decent holding power. Kind of like a "wobble" when it's trying to return to neutral. Seems like it would make for some interesting tail-wagging in flight. The over center deflection is maybe 10-15% of full deflection. Should I be concerned about this servo? Maybe the potentiometer is worn out? I would appreciate any advice on what I should do about this. This is the first time I've had a servo do something like this in 9 years of flying. Thanks!

-Aaron