TM 9-2320-260-34-1
5-25. FUEL PUMP CALIBRATION (Contd)
i. Testing and Adjusting Pump Main Pressure
1. Set vacuum gage (5) to 8 in. (20.3 cm) HG, open throttle wide open and adjust speed to 2100 rpm.
2. Place selector valve (4) on test stand (2) to rotameter position and set fuel flow to 3.15 pph with fuel
flow control valve (1).
NOTE
Fuel pressure should be 172-178 psi (1186-1227 kPa).
3. Must fuel pressure if 172-178 psi (1186-1227 kPa) is not obtained on fuel pressure gage (3).
j. Testing and Adjusting Fuel Pressure
CAUTION
Be careful when drilling out ball bearing not to damage bore of
throttle shaft.
NOTE
Throttle shaft internal adjusting screw is covered by throttle
shaft ball in end of throttle shaft.
Perform step 1 if ball bearing was not removed previously,
1. Center punch and drill out ball bearing (6) with 0.25 in. (6,35 mm) drill bit.
NOTE
Screw adjusting screw clockwise to increase and counterclockwise
to decrease fuel pressure.
2. Set fuel pressure to 172-178 psi (1186-1227 kPa).
3. Using shaft installation tool, insert new ball (6) in throttle shaft (7).
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