TM 9-4310-397-14
(7) Leakage Test.
(a)
Check nozzle for fuel leakage past valve seat.
1
Position nozzle on nozzle tester with nozzle tip down.
2
Operate pump handle rapidly to firmly seat valve.
3
Raise pressure at nozzle to about 400-500 psi (2800-3500 kPa) (28-35 bar) under specified opening
pressure.
4
Watch for an accumulation of fuel around the nozzle orifices. If fuel drips from nozzle within 5
seconds, nozzle is considered a "leaker", and must be replaced.
(b)
Check nozzle for valve stem and guide bar.
1
Position nozzlewith tip slightly above the horizontal plane.
WARNING
Place a clear, protective shield around spray zone to avoid possible personal injury from
spray.
2
Raise pressureto 1500 psi (10,300 kPa) (103 bar) on test gauge.
3
Look forleakage from the return end of nozzle. After one drop, leakage should be 3-10 drops in 30
seconds. Rate based on use of No. 2 diesel fuel or an equivalent viscosity of test oil at 65-75° F (18-
24° C) ambient temperature.
(c)
If nozzle leakage is not within specified range, nozzle must be replaced.
d.
Adjusting.
WARNING
Fuel from the spray orifices can penetrate clothing and skin causing serious personal injury.
The nozzle tip should always be directed away from the operator. Enclosing the nozzle in a
transparent cover is recommended.
Before applying pressure to the nozzle tester, be sure that all connections are tight, and that
the fittings are not damaged. Fluid escaping from a very small hole can be almost invisible.
Use a piece of cardboard or wood, rather than hands, to search for suspected leaks.
If injured by escaping fluid, see a doctor at once. Serious infection or reaction can develop if
proper medical treatment is not administered immediately.
(1) Connect nozzle to nozzle tester per paragraph 6-3, c, (1).
(2) Close pressure gauge valve (Figure 6-8, 9) and flush nozzle by operating pump rapidly.
(3) Raise pressure on pump until nozzle opens (gauge drops sharply). A new or reconditioned nozzle should open at
3150-3250 psi (21700-22400 kPa) (217-224 bar). A used nozzle should have a minimum opening pressure of
3000 psi (20700 kPa) (207 bar).
6-9
