The easiest way to make adjustments on your Hunter rotor is to use a Hunter adjustment wrench. 

There are two adjustments that can be made on your rotor, the arc and the radius. The arc adjustment is responsible for changing the rotational pattern the head is going to cover. The factory setting and minimum arc on a Hunter rotor is 40 degrees, the maximum is a full 360 degrees.

Increasing the Arc:

1. Insert the plastic end of the Hunter adjustment wrench into the arc adjustment socket on top of the rotor.
2. Holding the nozzle turret at its right stop turn the wrench clockwise.
3. The wrench will stop turning when adjusted to the maximum arc (360 degrees), do not go past this stop. Forcing the adjustment further may result in the breakage of key components to the rotors operation. 

Decreasing the Arc:

1. Insert the plastic end of the Hunter adjustment wrench into the arc adjustment socket on top of the rotor.
2. The adjustment tool will stop turning once it has reached the minimum arc adjustment (50 degrees). Similar to the increasing of the radius caution must also be taken not to force the rotor key beyond the minimum radius reduction.

Your arc can be adjusted from 40 to 360 degrees.