Thanks for that I will calibrate the angles manuallly.
The motor's running current is 250mA, stall current is 1500mA. I have it hooked up to an external power suppply at the moment and in the long run I intend to run it off an external battery pack. I have the grounds of the PSU and arduino tied together.
If all I have connected to the pin on the arduino is the servo control wire is that a problem? If I connect the control wire via an opto transistor it gets very jerky. I am guessing the opto transistor cant switch quickly enough.
Any help on hooking up the motor properly would be appreciated!