A mower carrying a rotary cutting deck has a height of cut system for adjusting the vertical position of the deck relative to the mower frame for changing or adjusting the height of cut. The height of cut system comprises a pair of parallel cross shafts that carry a plurality of pivotal suspension linkages that connect to the deck, the cross shafts and linkages pivoting jointly with one another and with a pivotal control lever. One of the cross shafts carries a torsion spring to counterbalance the weight of the deck. The control lever is maintained in a plurality of adjusted pivotal positions by a height selection bracket fixed to the frame with the height selection bracket being capable of having its position changed or adjusted relative to the frame by a single adjustment bolt. Each suspension linkage has its effective length adjusted by turning a threaded adjuster carried at the upper end of a connecting rod that is part of each linkage to allow the deck to be leveled relative to a reference plane. The adjustment of the height selection bracket is accomplished without affecting the length adjustments previously made to any of the suspension linkages.