To prevent overheat of an engine by automatically stopping the engine by slidingly moving one end part of an interlocking plate obliquely downward on the fuel raw material side along a guide plate by a starting spring when one end part of the interlocking plate separates from an upper end part of a governor lever by damge of a pivotal pin or the like.

A mechanical governor 19 integrally swings a pair of levers 21 and 22 by unbalanced force between governor spring force 26 and governor force 27, and interlocks a rack pin 4 of a fuel injection pump 3 through an interlocking plate 5. When one end part 6 of the interlocking plate 5 is normally pivoted on an upper end part of a governor lever 1 by a pivotal pin 7, the rack pin 4 is positioned in a starting quantity increasing position at engine starting time by tensile force 10 of a strating spring 9. However, when one end part 6 of the interlocking plate 5 falls by damage of the pivotal pin 7 or the like, one end part 6 of the interlocking plate 5 slides obliquely downward on the fuel raw material side along a guide plate 12, and the rack pin 4 moves up to a fuel uninjectable position, and an engine is automatically stopped.