TM 9-2320-260-34-1
5-25. FUEL PUMP CALIBRATION (Contd)
CAUTION
Fuel pump must pick up fuel at 500 rpm without priming. If
no fluid pickup is indicated at rotameter, inspect fuel filter for
improper installation, motor switch for correct rotation, open
suction valve and hose, and gear pump connections are tight.
Failure to do so may cause damage to equipment.
NOTE
Test stand rpm speed is controlled by fast and slow buttons.
10. Start test stand (1) by depressing start button (7).
11. Run to 500 rpm using speed control buttons (5) and (6).
NOTE
Check rotameter for air in fuel. If air bubbles are present, work
throttle from full open to idle several times to remove air from
fuel.
If air bubbles persist, turn test stand OFF and inspect all
connections for leaks.
If fuel pump is new or has been disassembled and reassembled,
run pump at 500 rpm for five minutes to allow bearings and
seals to seat and purge air from system.
d. Testing Pump Seals for Leaks
CAUTION
Do not leave fuel pressure valve closed more than five minutes.
Damage to fuel pump may occur.
1.
With test stand (1) operating at 500 rpm close fuel pressure valve (8) and open flow control
valve (11) on test stand (1).
2.
Test stand (1) vacuum should be 25 in. (63.5 cm), If not, check all test hose connections.
3.
Close bypass valve (9).
4.
Apply grease to weep hole (17) on fuel pump (4). If grease is pulled into weep hole (17) at 25 in.
(63.5 cm) vacuum, replace front cover (18) (para. 5-23).
5.
Apply grease around throttle shaft (16). If grease is pulled in replace throttle shaft (16) (para. 5-22).
6.
Apply grease to tachometer seal bore (13). If grease is pulled in replace fuel pump housing (14)
Open fuel pressure valve (8) on test stand (1).
7.
e. Testing Governor Cutoff RPM
1. Open fuel control valve (11) on test stand (1).
2. Using both the fast (5) or slow (6) button, increase fuel pump (4) speed to 2100 rpm.
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