Problems with Parallax Continuous servo sketch not working correctly

I am using the PARALLAX continuous rotation servo motor s. The knob sketch does noty do wha tis intended.

I tuned the servo to the stand position. But now the only thin the server does is move continuously left or right according to the direction I turn the potentiometer. This is not what I was expecting. I thought turning the know varies the speed of the servo or will stop at a angular position set in the potentiometer. Please advice. motor is loaded using 9V external voltage source.

That is what you would expect to see from a continuous rotation servo. You loose all the positioning. You might find there is a small change in speed when the angle fed to it is close to what ever the pot is set at that has been disabled. But depending on how the modification has been made it is likely that you would see no speed control.

Right.
For positioning - use a "standard" servo.