TM 5-3805-280-24-2
Fuel System
35
IMPORTANT: If any of the nozzle opening pressures
65
are not within specified range, reset
pressure and valve lift BEFORE
checking chatter and spray pattern.
Otherwise, these characteristics may be
affected. (See ADJUST FUEL
INJECTION NOZZLES later in this
group.)
CHATTER TEST
1. Close gauge shut-off valve and operate nozzle tester
at a pumping rate that will cause the nozzle to chatter.
Nozzle should chatter softly, and spray pattern should
be broad and finely atomized.
If nozzle fails to chatter, the nozzle valve may be bent
or tight in its guide due to accumulated lacquer
deposits. Disassemble nozzle and correct as detailed
later in this group.
NOTE: Until the chattering range is reached, fuel will
emerge in non-atomized streams.
2. Using the pumping rate for proper atomization, operate
tester for ten strokes. The nozzle must atomize on at
least eight of the ten strokes without consecutive
misses.
If the nozzle fails to meet this requirement, repeat
procedure. Nozzles which do not meet the requirement
after second test should be considered unacceptable
and should be either repaired or replaced.
SPRAY PATTERN TEST
1. Close gauge shut-off valve and operate nozzle tester
at a pumping rate that will cause the nozzle to chatter.
NOTE: Partially clogged, chipped, or eroded orifices will
cause the spray to deviate from the correct angle.
Spray will be streaky, rather than finely atomized.
2. Observe spray pattern and check for plugged orifices.
Continued on next page
RG,35,JW7592
1920NOV974/6
13-444
