To satisfy the starting properties of an engine on a slope, prevent speed variation when the engine is inclined, and prevent the excessiveness and shortage of fuel at rapid starting time and rapid stopping time, by regulating disturbance generated in a centrifugal governor when an on-vehicle engine is inclined, rapidly started and stopped.

The rack pin 5 of a fuel injection pump 6 is formed to be pushed and pressed on a fuel quantity reducing side by the governor force G of a governor weight 18 so as to be elastically pressed on a fuel quantity increasing side R by a governor spring 8 through a governor lever 1. A reservoir 12 for lubricant oil 11 is formed in the lower part of the pump storing chamber 10 of the fuel injection pump 6, and a balancer 13 having an eccentric load part 13a is dipped and vertically swingably arranged in the reversed lubricant oil 11. This balancer 13 and the neighborhood of the swinging base end of the governor lever 1 are connected together interlockingly through a buffer spring 14 so that the disturbance swing of the governor lever 1 is regulated through the buffer spring 14 by the self-retaining attitude of the balancer 13.