TM 10-4610-229-24
3-50. INJECTION NOZZLE REPAIR/TESTING (CONT)
3
Check pressure gage. It should show 2,200 psi when pump isolator valve is closed.
4
Wait 30 seconds, then read pressure gage. Pressure loss should be:
o
200 psi minimum
o
1,800 psi maximum
5
If pressure loss is not within this range, stop the test. Replace nozzle. If it is within this range, perform valve
opening pressure test (subpara d).
d.
Valve Opening Pressure Testing
1
Open pump isolation valve one-half turn.
2
Operate pump to increase pressure slowly until fuel comes from nozzle tip. Check gage.
3
Reading on gage should be 2,400-3,100 psi.
4
If valve opening pressure is not within this range, stop test. Replace nozzle. If it is within this range, flush nozzle
(subpara e).
e.
Nozzle Flushing
1
Close gage protection valve.
2
Close on-off valve.
3
Operate the pump rapidly for three full strokes.
f.
Tip Leakage Testing
1
Using rag, remove all fuel from nozzle tip and adapter. Make sure nozzle tip is completely dry.
2
Open gage protection valve.
3
Pump and hold pressure of 2,200 psi for 30 seconds. Watch tip of nozzle. A drop may form but should not fall
from nozzle tip.
4
If nozzle tip drips, stop test. Replace nozzle.
5
If nozzle passes test, perform orifice restriction test (subpara g).
3-124
