An actuator assembly for a rotatable sprinkler head includes a base supported for rotation on a stationary platform assembly, a hub mounted for rotation on a shaft supported in the base; a lever arm pivotally mounted at one end to the hub and extending downwardly toward a stop plate assembly on the platform assembly, the lever arm having a free end extending toward the stop plate assembly. The stop plate assembly is configured to define two or more distinct arcuate paths of travel for the lever arm, and the lever arm is adjustable to locate the free end in any of the three arcuate paths of travel.