When a rotary sprinkler would not shut off at the timer the gardener told me what to do by telephone. I must have damaged the part identified by an arrow in the photo by not loosening the nut first. The plumber did shut it down for me. The gardener may have worked on it since but I don't know for sure. The sprinkler works but the other valves are apparently fully open while the one on the left is somewhat closed still. I cannot find any tool to turn it back to the fully open position. Does it matter or will opening it up to the fully open position (if possible) allow more water to flow? Thanks for any thoughts.