A sprinkler device comprising: a sprinkler body having a nozzle and supporting a shaft having a cam (36, 78) mounted intermediate opposite ends of the shaft, a rotatable water distribution plate supported on one end of the shaft and adapted to be impinged upon by a stream emitted from said nozzle, said plate formed with grooves configured to cause at least said water distribution plate to rotate upon impingement of the stream; a hesitator assembly including a stationary housing supported in axially spaced relationship to said nozzle, and having a sealed chamber at least partially filled with a viscous fluid, with at least said cam located within said chamber; a rotor ring located within said chamber in substantially surrounding relationship to said cam, said rotor ring loosely located within said chamber for rotation and translation, having an inner peripheral edge formed with a plurality of hesitator lobes movable laterally into and out of a path of rotation of said cam, characterized by said rotor ring comprising an outer peripheral edge formed with a plurality of gear teeth selectively engageable with gear teeth on an inner surface of the stationary housing; wherein rotation of the water distribution plate begins a slow-speed interval when said cam engages and pushes past a respective one of said hesitator lobes, causing said rotor ring to incrementally rotate and to simultaneously move laterally, allowing said water distribution plate to begin a fast-speed interval, said fast-speed interval continuing until said cam engages another of said hesitator lobes to begin another slow speed interval, such that a rotational position where said cam engages said hesitator lobes continually changes as said water distribution plate rotates. a sprinkler body having a nozzle and supporting a shaft having a cam (36, 78) mounted intermediate opposite ends of the shaft, a rotatable water distribution plate supported on one end of the shaft and adapted to be impinged upon by a stream emitted from said nozzle, said plate formed with grooves configured to cause at least said water distribution plate to rotate upon impingement of the stream; a hesitator assembly including a stationary housing supported in axially spaced relationship to said nozzle, and having a sealed chamber at least partially filled with a viscous fluid, with at least said cam located within said chamber; a rotor ring located within said chamber in substantially surrounding relationship to said cam, said rotor ring loosely located within said chamber for rotation and translation, having an inner peripheral edge formed with a plurality of hesitator lobes movable laterally into and out of a path of rotation of said cam, characterized by said rotor ring comprising an outer peripheral edge formed with a plurality of gear teeth selectively engageable with gear teeth on an inner surface of the stationary housing; wherein rotation of the water distribution plate begins a slow-speed interval when said cam engages and pushes past a respective one of said hesitator lobes, causing said rotor ring to incrementally rotate and to simultaneously move laterally, allowing said water distribution plate to begin a fast-speed interval, said fast-speed interval continuing until said cam engages another of said hesitator lobes to begin another slow speed interval, such that a rotational position where said cam engages said hesitator lobes continually changes as said water distribution plate rotates.