Yanmar YM276 Service Manual page 181

Fuel System
30-10-21
-
CLEANING AND INSPECTION (Continued)
Nozzle Holder
lnspect t h e lapped machined surface on bottom end of nozzle
holder ( 0 ) for nicks or scratches. Minor defects may be removed
by lapping machined surface of nozzle holder on lapping Plate
(A) with lapping compound. When lapping holder, use a figure-8
pattern a s shown in the illustration.
Replace holder i f it can
not be restored t o a good, serviceable condition.
lnspect threads on nozzle holder for general condition. Threads
that are nicked slightly may be "dressed-up". Replace holder if
threads can not be restored t o
a
serviceable condition.
Check fuel passage (C) in nozzle holder to make sure that
it
is
open. Clean with compressed air.
Nozzle Retaining Nut
Remove carbon deposits on both inner and outer surfaces of the
-
nozzle retaining nut.
lnspect the retaining nut for
a
damaged lower seating surface
(seats against head insultating packing on precombustion chamber).
A
seating surface may be restored by rubbing the surface on emery
cloth.
Any nozzle retaining nut which cannot be reconditioned, must
be replaced with a new one.
Upper Holder Nut
Inspect upper holder nut for condition of threads and spring
seating surface. Thread sizes are shown in the above illustration.
Replace nut if it can not be restored t o a serviceable condition.
Nozzle Valve Spring
Examine spring and shims for pitting or excessive wear. Replace,
if not in good condition.