To avoid a false backdash reading in the following check, be sure the fuel pump end of the
cover (11) faces up. Turn the drive shaft (31 ) gently to avoid angular movement of the
unsupported drive shaft end.
Install the lower weight carrier assembly (4) in the cover (11), and check the backlash of the fuel pump
drive gear (28) and governor gear (9) as in step (1) (b), above. Back lash must be between 0.005 to 0.009
inch (0.13 to 0.23 mm).
Using masking tape such as A-A-883A, secure the spider (19) to the fuel pump drive coupling (23) for use
at installation on the engine.
The following adjustment is only an approximation used as a starting point in the calibration
procedure. The exact plunger protrusion will be set during the calibration procedures.
Install the weight assist spring (3), shims (2), shoulder pin (1), and check the pin protrusion with gage ST-
1241. Add or remove shims (2) to achieve a pin protrusion of 0.890 inch (22.61 mm).
Reassemble the fuel pump in accordance with paragraph 6-9.
6-11. FUEL PUMP TEST AND CAUBRATION.
General. The test and calibration procedure sets the fuel pump to the correct delivery standards. Test
specifications are summarized in 6-3. After calibration, it may be necessary to carry out minor adjustments on
the engine in accordance with paragraph 6-9. Test stand 3375698 is used to perform testing and calibration
procedures (figures Figure 6-15, Figure 6-16, and Figure 6-17). The test oil referred to in the following steps is
Oil the tachometer gears (17 and 24, Figure 6-12)with clean lubricating oil MlL-L-9000to provide lubrication
during the testing and calibration procedure.
Position the fuel pump to the pump drive adapter (2, Figure 6-15) on the fuel pump test stand (5), and
adjust the coupling (3) to give 0.062 inch (1.57 mm) clearance between the coupling and coupling spider
(19, Figure 6-12).
Attach the fuel pump to the pump drive adapter (2, Figure 6-15) using the capscrews (33, Figure 6-5),
lockwashers (34), and washers (35). Cross-tighten the capscrews to 40 to 45 pound-feet (54 to 61 newton-
Open the shutoff valve (Figure 6-10) by turning the knob (2) clockwise as far as it will go. Do not force.
This will lift plate valve (11) off its seat on valve housing (1) and allow for full fuel flow through the shutoff
valve during the calibraton process.
Prime the gear pump assembly (18, Figure 6-8) by squirting some dean test oil through the suction side of
the fuel inlet fitting (4).
Connect the fuel supply, outlet and return hoses (5, 1, and 3, Figure 6-16) in accordance with Figure 6-16.
Turn on the temperature control switch (17, Figure 6-17).
Loosen the hexagonal nuts (54, Figure 6-11) and back out the adjusting screws (55) completely so that
they do not interfere with the free movement of the control end (51) on the throttle shaft (45).
The throttle shaft (45, Figure 6-11) located in the fuel pump housing (66) turns counter
clockwise to open. The throttle shaft (30) located in the cover (23) turns clockwise to open.
Lightly damp a pair of locking pliers on the splined end of the throttle shaft (45) to be used as a lever.
Hook one end of a universal spring to the handle of the locking pliers, and hook the other end of the spring
to a point on the pump drive adapter (2, Figure 6-15). The handle of the locking pliers should be in a near
vertical position over the throttle shaft (45), and the spring tension should be maintaining the throttle shaft
(45) in the fully open position (rotated fully counter clockwise).