Liquid fuel injection pumping apparatus

A liquid fuel injection pumping apparatus for supplying fuel to an internal combustion engine and comprising a housing, an injection pump located within the housing and adapted to be driven in timed relationship with an engine with which the apparatus is associated, said injection pump including a rotary part supported within the housing, a bore defined in said rotary part, a plunger movable in said bore, an angularly adjustable cam ring surrounding said part and having angularly spaced cam lobes, a roller engaging said cam ring and positioned between the cam ring and the plunger, an outlet connected to said bore and through which fuel flows during movement of the plunger by the cam lobes, a fuel feed pump for supplying fuel to said bore to effect outward movement of the plunger in the direction opposite to that effected by the cam lobes, said fuel feed pump being driven by said rotary part, a control device for determining the amount of fuel supplied to the injection pump from said fuel feed pump, a pair of stop rings positioned at the opposite ends of the roller for limiting the outward movement of the plunger thereby to control the maximum amount of fuel which can be supplied by the injection irrespective of the setting of said control device, the spacing of said stop rings being temporarily adjustable to allow additional outward movement of the plunger so that the injection pump can supply an additional amount of fuel for starting purposes, a first ring member mounting one of said stop rings, said first ring member being axially and angularly movable within the housing, a second ring member positioned in side by side relationship to said first ring member, means locating said second ring member against axial movement in the direction away from the other stop ring, adjustment means for providing limited angular adjustment of said second ring member, interengageable formations on the adjacent side faces of said ring members whereby relative angular movement of said ring members will result in relative axial movement thereof, a piston cylinder combination mounted on said housing, means connecting said piston to said cam ring whereby movement of the piston within the cylinder will impart angular movement to the cam ring to adjust the timing of delivery of the injection pump, passage means connecting said cylinder with the outlet of the feed pump, a peg engaged with said first member, a slot for guiding the movement of the peg between extreme positions, the peg during movement from one extreme position to the other imparting angular movement to said first ring member, the spacing of the stop rings in said one extreme position being such that the normal maximum amount of fuel can be delivered as determined by the setting of said adjustment means, and in said other extreme position the spacing of the stop rings being such that excess of fuel can be delivered, resilient means acting to bias said peg towards said one extreme position, catch means for retaining said peg in said other extreme position, said catch means including a pin member engaging said cam ring and operable by said cam ring whereby when said cam ring is moved angularly by said piston said catch means is released to allow the peg to assume said one extreme position.