That idle speed is not mechanically controlled.It is set to spec at around 700 by communication between the sensors and the ECM.What are you trying to accomplish?
Agree with hondon, idle speed is controlled by the ECM.
A bad sensor could cause this. Could be caused by throttle cable is not hanging up. Have you got a manual ?
In general, their should be an adjustment for the base throttle setting/opening, but be sure, don't start turning screws. Each individual throttle body will have it's own adjustment, but don't touch!!!!