icrashgood

I have a "You Can Do 60 3d" and it has a JR NES 4735 servo on the Rudder. The problem is that when it is turned on it sits and oscillates back and forth about 3 inches from center... You can stop it with your fingers and it will be still but just touch it and it starts again. I have it on a Futaba system with a 4.8 volt battery, and I was wondering if a 6 volt battery will help.. I bought the plane used and haven't checked the wiring for the servo but it goes in the right direction and works OK other than the oscillation problem. Any help would be appreciated..
THank You
ICRASHGOOD