Turn the head all the way to the left and then all the way to the right. Make the adjustment with the head in this position. Insert the screwdriver or the plastic end of the key into the arc-adjustment hole and turn it clockwise to increase the arc width — once again, a full turn adds 90 degrees.Click to see full answer. Also know, how do you adjust a 360 degree sprinkler head?To increase the arc of your Hunter rotor head, you’ll want to insert the plastic key into the adjustment socket, which can be found on the top of each sprinkler head. Turn the adjustment wrench clockwise in a full 360-degree motion. This will increase your arc by 90 degrees each time you turn the wrench a full circle.Additionally, why won’t my sprinklers rotate? When the water pressure is too low, an inadequate amount of water flows through the sprinkler head and it will not turn. Using a larger backflow preventer in the water line might increase the water pressure enough to cause the sprinkler head to rotate. Also asked, how do you adjust the water flow on a sprinkler head? With a screwdriver, adjust the radius screw located on top of the sprinkler head. Turn the radius screw clockwise to lessen the water flow. Turning the radius screw of your sprinkler will introduce friction to your sprinkler nozzle and reduce the amount of water coming into your sprinkler system.How do you fix a sprinkler that won’t rotate? How to Do It Disassemble the sprinkler head. Take off the filter at the bottom of the head. Rinse the filter in a bucket filled with clean water to wash out debris. If this doesn’t work you’ll need to have the sprinkler head replaced. If it does work, make sure the head is properly adjusted when you re-install it.