A walk-behind lawnmower and accompanying method of use allows for height adjustment of the cutting deck relative to all four wheels simultaneously. This is achieved using a linkage that runs along the cutting deck and that connects the front and rear wheel assemblies. Movement of the entire mechanism is achieved using a lever operatively connected to the linkage. The linkage is retained in place through the use of a locking mechanism. The locking mechanism includes a locking pin, a pin engagement mechanism, such as a lug, provided on the linkage, and an array of pin receptacles spaced longitudinally along the cutting deck. The pin engagement mechanism selectively engages the pin when the pin engages a designated pin receptacle on the cutting deck, retaining the cutting deck at a height determined by the prevailing location of the pin which, in turn, is determined by the selected pin receptacle.