Using a servo motor as a motor or a servo
The problem you have now is that by removing the pot your servo does not know where it currently is ( there is no feedback ), this could be helpful if you wanted to make it act as a motor, but then you have to remove the pot inside the servo and replace it with 2 fixed resistors of the same value as the pot eg. 10k pot then use two 5k resistors, sothat the servo thinks its still in the neutral position ( exactly in the middle of its range ) and then remove the limiter on the gear you can now control the servo by still giving it its initial pulses eg. Using the servopos command like
servopos 4.150 (now it souldn't move you might need to fine tune it like maybe setting the pulse at 149 or 151 all depends on your servo but normaly this is the null point)
now then if you then take your pulse down from 150 your servo wil start moving slowly in the one direction and the more you take your pulse down the faster it wil go but do not take it down more than 75 as this is normaly the pulse to drive it to its max position on the one side, but it wouldn't stop because it is looking for the feedback to know where it is but its not getting it.
Now if you would then increase your pulse to more than 150 it would move to the other direction and the more you increase it the faster it wil rotate but then do not go more than 250 as this is normaly the pulse to drive it to its max position in the other direction.
Now all of this is usefull if you want to use a servo as a motor but still be able to control its direction and speed via one wire and one command and still have all your servo torque, but then to change it back . . .
You are going to have to put back your initial pot or if not a pot of equal value sothat the servo now know were it is and now you can use the same commands but it wil only move to the position equal to the pulse eg. Servo 4.150 would be in the middle, servo 4.75 all the way to the one side and servo 4.250 all the way to the other side, these pulses may slightly change according to your servo but is normaly around there.
As for your limiter, it is not that important unless you sent a pulse to the servo that is out of its initial range then it would jitter and not know were it is going so to be safe stay between a pulse of 85 and 200. Again interperate these values for your servo they might change slightly.
Hope all of this could help you in some way or another.