There are two ways to easily realign the right arc position:
1. Turn the whole sprinkler body assembly and the fitting below it to the desired position. (You may first need to remove some soil around the sprinkler to allow you to grip the sprinkler housing).
2. Turn the body cap counterclockwise and remove the internal assembly from the body. Rotate the nozzle turret to the right stop, screw the internal assembly back into the body with the nozzle aligned to the desired irrigation area and adjust the left arc as needed.