PURPOSE: To stable idling and prevent occurrence of engine stall irrespective of quality of fuel.

CONSTITUTION: A governor sleeve 17 slidably journalled by a governor shaft 3 penetrating a fly weight case 2 is engaged with the fly weight case 2 which is rotationally driven by a gear provided on a drive shaft of a distributor type fuel injection pump. A governor sleeve 17 abuts against a group of governor levers which are connected to a control sleeve for adjusting a fuel injection amount, which sleeve 17 is displaced in an axial direction of the governor shaft 3 according to displacement of a fly weight 6 housed in the fly weight case 2.