TM 9-2910-226-34 Figure 1-26. Fuel delivery flow diagram. Figure 1-27. End of fuel delivery flow diagram. 1-24. Fuel Metering and Control. a. The quantity of fuel delivered per stroke is governed by variation in the position of the plunger sleeve (fig. 1-27) with relation to the fixed port closing position (the point at which the top of the fuel plunger covers the fuel 1-28 ports). As the spill passage in the fuel plunger breaks over the top edge of the plunger sleeve, pumping pressure is relieved and fuel delivery terminates despite continued upward movement of the fuel plunger. b. When the plunger sleeve is raised, the spill passage remains covered by the plunger sleeve until relatively late in the plunger stroke. Hence, the effective stroke of the fuel plunger is longer and more fuel is delivered. When the plunger sleeve is lowered the spill pas sage is uncovered by the plunger sleeve relatively sooner in the plunger stroke. Hence, the effective stroke of the fuel plunger is shorter and less fuel is delivered. c. When the plunger sleeve is lowered to its ex- treme point, the spill passage is uncovered by the top edge of the plunger sleeve before the upper end of the fuel plunger can cover the fuel ports. Under this condition, no pressure can be built up and no fuel can be delivered. This is the fuel shutoff position. 1-25. Speed Governing (Typical). NOTE The key letters shown below in parentheses refer to figure 1-19 except where otherwise indicated. a. The camshaft has two forged governor weights (UU, fig. 1-16) attached to it through pins in a spider. As camshaft speed increases, the weights move out ward away from the camshaft. Fingers on the weights act against the sliding sleeve (VV, fig. 1- 16). b. The sliding sleeve is compressed against the fingers of the governor weights by the governor inner and outer springs (RR and SS, fig. 1-16). The tensions of these springs balance the action of the governor weights at any given speed within the normal range after the sliding sleeve has shifted. Therefore, at any given engine speed, there is a definite corresponding sliding sleeve position. c. The sliding sleeve is connected to the fulcrum lever (B) through pivot pins (G, fig. 1-19). The fulcrum lever slides in grooves in the sliding sleeve and as the sliding sleeve moves, the fulcrum lever moves. The fulcrum lever is also connected through linkages to the plunger sleeve in the hydraulic head. - As noted in paragraph 1-23 above, the position of the plunger sleeve determines the quantity of fuel delivered. d. The fulcrum lever is also pivoted (H, fig. 1-19) at its lower end on a yoke (an integral part of the fulcrum lever) which is connected to the operating shaft (E). The operating lever (F), which connects to the operating shaft, is actuated through linkage from the vehicle driver’s compartment. The position of the operating lever determines fuel delivery and engine speed. e. With the operating lever in a stationary position, the lower pivot of the fulcrum lever becomes fixed. If the engine load is increased, the engine speed will momentarily decrease and the governor weights will lack the centrifugal force necessary to balance the spring forces on the sliding sleeve. The fulcrum lever then shifts and moves the