Abstract: To control the speed of a lawn mower, the speed of the lawn mower is changed in a forward direction along a longitudinal plane, resulting in a tendency to turn because of different speed characteristics of the right and left wheel drives. The speed is corrected by lateral movement of a control lever to increase the speed of one wheel motor and decrease the speed of the other wheel motor. When turning, if the lawn mower is not aligned along the longitudinal axis after the turn, the deviation is indicated in the position of the control lever to the right or left. This can be corrected by momentarily applying a motor speed change to one of said right and left hydraulic motors while observing the control lever until the control lever is centered in the longitudinal plane, whereby the speed of the lawn mower will be aligned along the longitudinal plane.