Figure 3-173. Idle and High speed adjustment.

TM 9-2910-226-34

linkage (para 3-25). Replace defective parts,

supply filters. Then if pressure is still low, replace

and repeat the tests to obtain specified fuel

the over-flow valve. Fuel flow should be in ac-

flow. Check governor spring and spacers

cordance with Table 3-4 or 3-5, depending on pump

(fig. 3-142, 3-143, 3-144, and 3-145).

used. If reading in the burette (F, fig. 3-162) is not

within specifications, push in the fuel dumping lever

(E) to clear the burettes, and repeat test. If reading

is not within specifications, push in fuel dumping

lever to clear burettes. Fuel flow adjustment is made

by adjusting high speed adjustment screw (fig. 3-

173). Loosen the hex nut and turn the screw clock-

wise to decrease, or counterclockwise to increase the

fuel delivery. Make adjustments and repeat test

until specified fuel flow is attained. Tighten hex nut

to lock setting of the high-speed adjustment screw

F'igure 3-174. Adjusting stop plate guide screw and stop plate

for desired fuel delivery (code C, D, and E pumps).

(4) Increase pump speed to 2940 rpm and check

fuel flow. Flow should be 5 cc or less. If reading of 5

cc or less is not obtained, it will be necessary to stop

the test and check the high speed (inner) governor

spring spacer(s). See Table 3-11 for proper spacer

dimensions (refer to para 3-43). Check for use of the

correct spring (fig. 3-143). Check control unit for pin

wear (para 3-44).

NOTE

Adding spacers to the governor spring will

increase fuel delivery, and decreasing

spacers will decrease fuel delivery. Repeat

2940 rpm fuel flow check, and add or remove

spacers to obtain a fuel flow of 5 cc

Figure 3-173. Idle and High speed adjustment.

maximum.

(5) Adjust speed to 1400 rpm and check fuel

Table 3-10. Fuel Supply Pump Pressure (To Hydraulic Head)

pressure on gage (A, fig. 3-162) at compensator

inlet. Fuel pressure should be 40-55 psi. Check fuel

Speed [rpm]

Pressure [psi]

flow per Tables 3-5 or 3-4 respectively. (This is a

2600-3100

60-80

reference point only,) No adjustment is required on C

1200

40-55

and D pumps. Adjust setscrew (droop screw) (J, fig.

700

30-40

3-67) on code E pumps. Turn screw clockwise to

150

7 (min. )

decrease fuel delivery, and counterclockwise to

(3) Adjust speed to 2600 rpm and check fuel

increase fuel delivery. (Code C and D pumps do not

pressure on gage (A, fig. 3-162) at compensator

have a droop screw.)

inlet. Fuel pressure should be 60-80 psi. Adjust stop

(6) If fuel flow cannot be adjusted to these

plate guide screw (fig. 3-174) on code C, D, and E

limits, check engagement of compensator stop plate

pumps, or (fig. 3-172) on code G pumps, to obtain

and linkage on code C, D, and E pumps and angular

fuel flow per Table 3-4 or 3-5.

position of smoke limit torque cam on all pumps

NOTE

(table 3-8). (Refer to figure 4-73.) Raising the cam to

Turn stop plate adjusting nut clockwise to

a greater angle will increase fuel flow and decreasing

decrease fuel and counterclockwise to in-

the cam angle will decrease the flow. Recheck fuel

crease fuel, as viewed at the governor end of

flow.

the pump. If fuel flow limit can not be ob-

(7) Reduce speed to 700 rpm and check fuel

tained by adjusting the stop plate, it will be

pressure on gage (A, fig. 3-162) at compensator inlet

necessary to inspect the fuel control rod

(code C, D, and E pumps) or head inlet (code G

3-106