TM 5-3810-300-24&P-3
Fuel Injector
2.1.1
Remove the carbon deposits from the lower inside diameter
CAUTION: Care must be exercised when
taper of the injector nut with carbon remover.
inserting the carbon remover J 946441 in
the spray tip to avoid contacting the
needle valve seat in the tip.
Clean the spray tip orifices with pin vise J 4298-1 and the
proper size spray tip cleaning wire. Use wire J 21460 to
clean .0055"diameter holes and wire J 21461 to clean
Before using the wire, hone the end until it is smooth and
free of burrs and taper the end a distance of 1/16"with
stone J 8170. Allow the wire to extend 1/8" from tool J
4298-1.
Fig. 33 - Lapping Spray Tip on Lapping Blocks J 22090
The exterior surface of an injector spray tip may be cleaned
by using a brass wire buffing wheel, tool J 7944. To obtain
J 941l85 Fig. ()i. Use care to minimize removing metal or
a good polishing effect and longer brush life, the buffing
setting up burrs on the spray tip seat. Remove only enough
wheel should be installed on a motor that turns the wheel at
metal to produce a clean uniform seat to prevent leakage
approximately 3000 rpm. A convenient method of holding
between the tip and the nut. Carefully insert carbon
the spray tip while cleaning and polishing is to place the tip
remover J 9418-1 in the injector nut. Turn it clock\fs16 wise
over the drill end of the spray tip cleaner tool J 1243 and
to remove the carbon deposits on the flat spray tip seat.
hold the body of the tip against the buffing wheel. In this
way, the spray tip is rotated while being buffed.
Wash the injector nut in clean fuel oil and dry it with
compressed air. Carbon deposits on the spray tip seating
CAUTION: Do not buff excessively. Do
surfaces of the injector nut will result in poor sealing and
not use a steel wire buffing wheel or the
consequent fuel leakage around the spray tip.
spray tip holes may be distorted.
When handling the injector plunger, do not touch the
When the body of the spray tip is clean, lightly buff the tip
finished plunger surfaces with your fingers. Wash the
end in the same manner. This cleans the spray tip orifice
plunger and bushing with clean fuel oil and dry them with
area and will not plug the orifices.
the side of the bushing is not plugged. If this hole is
Wash the spray tip in clean fuel oil and dry it with
plugged, fuel leakage will occur at the upper end of the
compressed air.
bushing where it will drain out of the injector body vent and
Clean and brush all of the passages in the injector body,
dilution problem. Keep
using fuel hole cleaning brush J 8152 and rack hole
cleaning brush J 8150. Blow out the passages and dry
Carefully insert reamer J 21089 in the injector body (Fig.
29). Turn it in a clockwise direction a few turns, then
remove the reamer and check the face of the ring for
reamer contact over the entire face of the ring.
If
necessary, repeat the reaming procedure until the reamer
does make contact with the entire face of the ring. Clean
up the opposite side of the ring in the same manner.
Carefully insert a .375" diameter straight fluted reamer
inside the ring bore in the injector body. Turn the reamer in
a clockwise direction and remove any burrs inside the ring
bore. Then wash the injector body in clean fuel oil and dry
it with compressed air.
Fig. 34 - Location of Filter in Injector Body
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