TM 9-2320-272-24-4
5-18. FUEL PUMP SETUP AND CALIBRATION (Contd)
f. Testing and Adjusting Throttle Leakage
Increase fuel pump (9) speed to 2,100 rpm with fuel pump throttle lever (13) and place selector valve (7)
1.
to ROTAMETER position to see if any air is in system.
NOTE
At 2,100 rpm fuel flow, ROTAMETER FLOAT should read 315 pph
on the scale.
2.
Set fuel flow control valve (8) for 315 pph reading.
3.
Place selector valve (7) to LEAKAGE TEST position and place count selector switch (6) to the 1,000
position.
Pull out dumping lever (2) to retain fuel in No. 1 burette (3).
4.
CAUTION
Do not hold throttle lever in idle position any longer than two
minutes to complete test. Pump may overheat, since fuel flow is
used to cool the pump.
5.
Remove throttle spring (4) and manually position throttle lever (14) to idle position.
6.
Depress pulse counter button (5) to fill No. 1 burette (3).
7.
Push dumping lever (2) inward.
NOTE
l Ensure burette is cleared of fuel in order to prevent overflow at
this time.
l A test cycle is one-half minute duration.
l For one half minute cycle, fuel delivery is 40-70 cc.
8.
At the end of a cycle, read the amount of fuel in number one burette (3) on the scale.
9.
If throttle leakage is not as specified, back rear throttle screw (12) out to decrease leakage and in to
increase leakage.
g. Testing and Adjusting Idle Speed
1.
Place selector valve (7) to IDLE position and increase fuel pump (9) rpm to 500.
2.
Pull fuel pump throttle lever (13) to idle position.
3.
If fuel pressure is not 26 psi (179.27 kPa), adjust idle screw (10) in governor spring pack housing (11)
using adjusting tool.
4.
If pressure is low and the adjusting screw bottoms, stop the test stand, add shims to the spring end
of the adjusting screw (para. 5-14), and retest cutoff rpm and throttle leakage, tasks e. and f.
NOTE
Each time governor spring pack housing or adjusting tool is
removed, run pump until purged of air.
5.
After proper adjustment is made, stop the test stand (1) and remove adjusting tool.
6.
Install 1/8 in. (3.17 mm) pipe plug (14) removed in steps 17 and 18, task b.
7.
Purge the fuel pump (9) of air.
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