Cleaning - TM-10-3930-634-340057

TM 10-3930-634-34

NOTE

(5) Lift the injector nut (1, fig. 3-42) straight up

Make sure the stroke counter (fig. 3-39) on

being careful not to dislodge the spray tip (2) and valve

the comparator is preset to 1,000 strokes. If

parts. Place all parts in a clean receptacle.

for any reason, this setting has been altered,

(6) When an injector has been in service for some

reset the counter to 1,000 strokes by pulling

time, the spray tip, even though clean on the outside

the selector to the right and rotating it to the

may not be pushed readily from the nut with the fin-

proper position. Then, release the wheel.

gers. In this event, support the nut on a wood block

2. Pull the injector rack out to the NO FUEL

and drive the tip through the nut as illustrated in

position.

figure 3-43.

3. Start the comparator by turning the switch

e. Cleaning and Inspection.

to the ON position.

(1) Cleaning.

4. After the comparator has started, push the

(a) Wash all parts with clean fuel oil and dry

injector rack in to the full fuel position and allow the

with clean, filtered compressed air.

injector to operate for approximately 30 seconds to

(b) Carbon on inside of spray tip may be

purge the air that may be in the system.

loosened for easy removal by soaking about 15 minutes

5. After 30 seconds, press fuel flow start but-

in a suitable solution prior to external cleaning and

ton. This will start the flow into the vial. The compara-

buffing operation. (Metye Etheyl Ketone solution is

recommended.)

tor will automatically stop the flow of fuel after 1000

strokes.

CAUTION

6. After the fuel stops flowing into the vial,

Care must be exercised when inserting ream-

pull the rack out to the no fuel position.

er in spray tip to avoid contacting needle

7. Turn the comparator off and reset the

valve seat in the tip.

counter.

(c) Clean spray tip with a reamer as shown in

8. Observe reading on vial of comparator. In-

figure 3-44. Turn reamer in a clockwise direction to

jector fuel output must be within limits indicated for

remove carbon deposits. Wash spray tip and dry with

the applicable injector listed below.

compressed air.

Fuel Output

(d) Clean the spray tip orifices with a pin vise

(Cubic MM)

Injector

and proper size spray tip cleaning wire as illustrated in

Min

Max

figure 3-45. Before using a wire, hone the end of the

L40

wire until it is smooth and free of burrs using a fine

N40

stone. Allow the wire to extend 1/8 in. from the tool.

N45

N50

(e) Clean the exterior surface of the spray tip

M65

using a brass wire buffing wheel. Place the tip over the

drill end of the spray tip cleaner tool and hold the body

If quantity of fuel in the vial does not fall within speci-

of the tip against the buffing wheel. In this way, the

fied limits, disassemble injector and inspect tip and

spray tip is rotating while being buffed.

valve parts for damage.

(f) When the body of the spray tip is clean,

lightly buff the tip end in a similar manner. This

select a set of injectors which will inject the same

cleans the spray tip orifice area and will not plug the

amount of fuel in each cylinder at a given throttle

orifices.

setting, thus resulting in a smooth running engine.

(d) An injector which passes all the above tests

(g) Wash the spray tip in clean fuel oil and dry

with moisture free compressed air.

can be put back into service. However, an injector

(h) Clean and brush passages in the injector

which fails to pass one or more of the tests must be re-

paired or replaced.

body, using fuel hole cleaning brush and rack hole

cleaning brush. Blow out the passages and dry with

d. Disassembly.

compressed air.

(1) Support the injector upright in the injector as-

(i) Carefully insert reamer in the injector body

sembly fixture tool or in injector vise jaws. Disassem-

as illustrated in figure 3-46. Turn the reamer in a

ble the injector filter in numerical sequence as illus-

clockwise direction a few turns; then remove the

trated in figure 3-40.

reamer and check the face of the ring for reamer con-

(2) Remove the follower stop pin (fig. 3-35).

tact. If the reamer does not make contact over the en-

(3) Disassemble the injector follower, spring and

tire face of the ring, repeat the reaming procedure un-

plunger in numerical sequence as illustrated in figure

til the reamer makes contact with the entire face of

3-41.

the ring. Clean the opposite side of the ring in a similar

(4) Reverse the fuel injector in the fixture and dis-

manner.

assemble the remaining injector components in numer-

ical sequence as illustrated in figure 3-42.

(j) Carefully insert a 0.375 inch diameter

3-29