Abstract: A vehicle having a transmission with a power take-off employs a governor for regulating engine speed during use of the power take-off; vacuum responsive motor means operatively connected to the engine throttle serves to control the speed of the engine; the vacuum responsive motor is effectively operatively communicating through speed-responsive restruction means to a source of engine developed vacuum; additional valving means are provided as to also connect the vacuum motor directly by a separate path to the source of vacuum during certain engine operating conditions.