how to adjust a Irritrol rotor head

Arc Adjustments

POSITIONING NOZZLE TURRET TO ITS “RIGHT START"
Place your finger on the top center of the nozzle turret. Rotate the turret
counter-clockwise to the left stop to complete any interrupted rotation cycle.
Rotate the nozzle turret clockwise to the “right start.” This is the fixed side
of the arc. The nozzle turret must be held in this position for arc adjustments.
The “right start” does not change.
ADJUSTING THE RIGHT (FIXED) SIDE OF ARC
If the right side of the arc is not properly aligned, the sprinkler may spray in areas not intended for watering such as driveways or adjacent properties. The right side arc can easily be realigned.
- OPTION 1: REPOSITION CAN ON THE FITTING: Turn the sprinkler can and
  the fitting below it left or right to the desired position. This may require
  temporary removal of the soil around the sprinkler to allow you to grip the
  sprinkler can.
- OPTION 2: REMOVE INTERNAL RISER ASSEMBLY AND REPOSITION: Unscrew the top
  counter-clockwise and remove the internal riser assembly from the can. Once removed
  with nozzle turret at its “right start,” reposition riser assembly so that nozzle arrow points
  to the desired start position. Replace riser assembly back in the can and screw on the top.
  At this point you have realigned the right arc stop, and you can adjust the left arc to an
  appropriate setting.
ADJUSTING THE LEFT (VARIABLE) SIDE OF THE ARC
- INCREASING THE ARC: Insert the plastic key end “D” of the universal tool into the arc set adjustment slot. While holding the nozzle turret at the “right start,” turn the universal tool clockwise. Each full 360° turn of the universal tool will increase the
  arc 90°. Adjust to any arc between 40° and 360°. The universal tool will stop turning, or there will be ratcheting noise, when the maximum arc of 360° has been reached.
- DECREASING THE ARC: Insert the plastic key end “D” of the universal tool into the arc set adjustment slot. While holding the nozzle turret at the right start, turn the universal tool counterclockwise. Each full 360° turn of the universal tool will decrease the arc 90°. Adjust to any arc between 40° and 360°. The universal tool will stop turning, or there will be a ratcheting noise, when the minimum arc of 40° has been reached.