In one embodiment, a turf aerator includes a frame having wheels, a variable displacement pump, an engine for driving at least one of the wheels and driving the pump, a tine assembly supported by the frame and being movable between lowered and raised configurations, and a swash-plate-adjustment linkage extending from the tine assembly to the pump. The tine assembly includes: a base a hydraulic motor in hydraulic communication with the pump rotatable cranks powered by the hydraulic motor a downwardly-extending arm rotatably coupled to each crank a tine extending downwardly from each downwardly-extending arm springs operatively anchored to the base and a guide arm extending between each downwardly-extending arm and a respective spring. The swash-plate-adjustment linkage automatically adjusts the pump with movement of the tine assembly relative to the frame to provide output to the hydraulic motor substantially only when the tine assembly is at the lowered configuration.
