in fig8 will be first considered the principal elements of this mechanism include in addition to the drive control lever 32 and the blade control lever 34 an elongated hollow clutch rod member 38 a control lever mounting post 40 an off centered or eccentric cable actuating plate 42 and a spring biased hook type member 44 which operates in conjunction with the eccentric plate 42 as will become evident as this detailed description proceeds considering each of these elements now in greater detail the self propelling wheel drive lever member 32 for example comprises an open three walled structure having a pair of parallel side walls and a top cross wall with a side wall 46 having a pivot 48 located at the inner end thereof the pivot 48 fits into a circular mounting hole 50 in the upper intermediate region of the blade control lever 34 and permits the wheel drive lever 32 to be rotated up and down about the pivot 48 by manual activation of the crossbar 30 the outer end of the wheel drive lever 32 moreover is adapted to receive therein one end portion of the hollow clutch rod 38 which is pivotally attached thereto via a pair of throughholes 52 and 54 a pivot bolt 56 a pair of annular spacers 58 and 60 and a cap nut 62 also as shown in fig8 the pivot bolt 56 not only passes through a pair of throughholes 64 and 66 in the outer or distal end of the clutch rod 38 but also the end ring member 68 of a wheel drive clutch cable 70 which.