Servo problem ?

[Richard t]

I'm in the process of building my Losi 22 and I got out my brand new Spektrum servo and hooked it up to the reciever in my Xxxcr to center it well I then cycled it several times and it would start self cycling left to right but if I centerd the transmiter it would stop. So thinking I had a faulty brand new Spektrum I got out a brand new Savox servo and guess what it does the same ? But the plot thickens the servo in the Xxxcr is a less expensive, less torque slower speed Futaba and it operates fine?
Anyone have a suggestion, help....