TM 55-1930-209-14&P-21
b.
Inspection
(1)
Inspect teeth on control rack and control rack gear (Figure 5-10) for excessive wear or damage. Also,
check for excessive wear in bore of gear, replace damaged or worn parts.
(2)
Inspect injector follower for wear. Inspect both ends of spill deflector for sharp edges or burrs which
could create burrs on injector body or injector nut and cause particles of metal to be introduced into spray tip and valve
parts. Remove burrs with a 500 grit stone.
(3)
Inspect follower spring for defects and check spring with a spring tester and a torque wrench. Injector
follower spring (0. 142-inch diameter wire) has a free length of approximately 1. 504 inches and must be replaced when
a load of less than 70 pounds will compress to 1.028 inches.
CAUTION
A faulty sealing surface will result in high fuel consumption and contamination of lubricating oil.
(4)
Check seal ring area on injector body for burrs or scratches. Also check surface which contacts
injector bushing for scratches, scuff marks, or other damage. If necessary, lap this surface.
(5)
Replace any loose injector body plugs or a loose dowel pin. Install proper number tag on a
replacement injector.
(6)
Inspect injector plunger and bushing for scoring, erosion, chipping, or wear. Check for sharp edges on
that portion of plunger which rides in gear. Remove sharp edges with a 500 grit stone. Wash plunger after stoning it.
Use injector bushing 'Inspectalite" to check plunger bushing for cracks or chipping. Check locating pin in bushing. If pin
is damaged or sheared off, it must be replaced. Slip plunger in bushing and check for free movement. Badly worn,
chipped or scored plungers or bushings must be replaced. Plungers and bushings are mated parts and must be replaced
as an assembly.
CAUTION
Injector plungers cannot be reworked to change the output. Grinding will destroy hardened case
at the helix and result in chipping and seizure or scoring of plunger.
(7)
Examine the spray tip seating surface of injector nut for nicks or burrs. Reseat surface or replace nut if
it is severely damaged.
(8)
Inspect sealing surfaces of injector parts with a magnifying glass. The slightest imperfections will
prevent the Injector from operating properly. Check for burrs, nicks, erosion, cracks, chipping and excessive wear.
Check for enlarged orifices in spray tip. Replace damaged or excessively worn parts.
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