ENGINE DIAGNOSTIC TEST PROCEDURES
TEST INJECTION NOZZLES (Continued)
Injection Nozzle Testing
The prime requirements for a satisfactory nozzle
assembly are: pressure tight seats; no excessive
After removal from engine, test nozzles for
spray condition, opening pressure and leakage
on a hand test pump SE-2002.
Figure 24 shows an injection nozzle mounted
for testing on the hand test pump.
IT IS ADVISABLE TO TEST NOZZLES
BEFORE CLEANING THEM. AFTER TESTING
DECARBONIZING SOLUTION FOR AT LEAST
ONE HOUR. AFTER REMOVING NOZZLES
FROM SOLUTION, WASH OFF THE OUTSIDE
Prepare pump for making tests. Fill pump
reservoir with Viscor 1487C calibration fluid.
Open pump valve slightly and operate pump
handle to expel air from pump and outlet pipe.
Operate pump until solid fluid (without air
bubbles) flows from end of outlet pipe. Close
Connect injection nozzle to test pump. Avoid
securely with open end wrench.
Bleed air from nozzle. Open pump valve and
operate pump for several quick strokes to expel
(bleed) air from injection nozzle. Fluid should
spray from the spray holes in nozzle tip.
Figure 24. Typical Nozzle Assembly Mounted
in the Hand Test Pump
Nozzle Tube Assembly (SE-2004-13)
90 Adapter (SE-2757)
KEEP HANDS AWAY FROM NOZZLE SPRAY.
FLUID SPRAYING FROM THE NOZZLE
UNDER HIGH PRESSURE CAN PENETRATE
PROVIDED IMMEDIATELY IN THE EVENT OF
OBSERVE SPRAY PATTERN. Operate test
pump in smooth, even strokes and observe
pattern of fluid spraying from nozzle tip spray
holes. The spray should be well atomized in an
even pattern, free from solid streams and
dribbling. Examples of good and bad spray
patterns are shown in Figure 25.
Open gauge valve, operate test pomp in slow
smooth, even strokes and observe gauge
pressure to determine pressure at which nozzle
opens (sprays fluid). Nozzle should operate
within specified opening pressure range.
Printed in United States of America