MAINTENANCE
AND
ADJUSTMENT
1
one
second): tenrunating
mam
spray occurs when
the lever
IS
operated rapidly at a rate
of,
say, 4 to
6 cycles per second.
2 3
4
5
&
I1Il
I!!J
!U1J
IilJ
1\\
UlIJ
Ij\
1,C
OCId
4·Afte1'<iribble
2-S
IXllY
cone
tOO
ILI~!l~
S·Fiss
ure-
d spray
3·0Ir<:ente~
sp
rey S·Whi
rl
lng
-spr
ay
Possible
patterns
of
spray
(,)
Inltiill
throttled
spray
It,
l\11
00
When
the
nozzle
is
producing
onJy
this
sp
r
ay
I
atomization
is
g
enerally
poor
and
the
pattern
is
r'lher straight
Ih
...
conieol, there being more
Or
less after-dribble,
th'l
is,
fuel dribbling ,fter
mjection. All
th.~
are due
to
the fact th
't
the
fuel being
injected is
being
throttled
by the
pintle protruding from
the valve .
Wltile
the nozzle
is
making this spray, see
if
the
needle valve chatters in syncluonism with the
cyclic
motion
of
the lever;
if
so, then the needle
"a1ve
is
free from any sticking or hitching
tendency and, if not, the nozzle and needle
valve must
be
cleaned by
washing
and
r.
·t
esled.
Off-center spray
Or
directionally ernuic
spray
,
if
nOled, should be t
ake"
to
mean
Ihat the
injection nozzle n<ods thorough cleaning.
(b)
Terminating main spray
With
the
tester
lever
operated
at
a
rate
of
4
to
6 cycles per second, the initial
thr
o
tt
le spray
is
hardly visible. The spray under this condition
may
be
regarded
as
main
spray
.
The "Jain spray should
be
a good straight cone,
about
OQ
in
angle~
comisting
of
fmely
atorruzed
fuel
partic-les
with
ou
t
any
large
droplets,
and
.hould terminate with no dribble at the tip,
nol
to mention
of
any
fu
el dripping.
(3) Seating tightness
78
An
inje
ction nozzle
tested
and
ad
justed
as
above,
and found
to
produ
ce a good spray pattern may
b.
re·used in the engine provided
that
it
passes
lhis ftnal lost - seating
tightn."
te
st.
WIth
the injection nozzle mounted on the nozzle
tester,
raise the pressure
slowly
to 100 or 110
kg/cm'
(1422
Or
1564 psi)
(without
exceeding the
s
et
pre
ssure of 120 kg/em'
(1706
psi). so
thatth.
needle valve
will
not
unseat).
Hold
the pressure
and
observe the
no
zzle tip: there should
be
no
evidence
of
fuel oozing
oul
to
form a dribble.
If
such evidence is noted,
th
en the c
onta
cting faces
of
the needle valve and s
••
t must be repaired by
lapping in the manner already
su
ggested
Or
the
injection nozzle
as
a whole must be replaced.
Cooling
system
FJU>bi
ng
service
Even
drinki.ng
water
conta
in
s one
or
m
Ore
su
bstan<:e5
in
extremely small quanti
ti
es
as
impurities.
In
the engine
in
us
e,
the
cooling
wate
r deteriorates
-g
ra
dualJy:
the
con
-
centrations
of
impurities increase progresslvely to form
sludges
,
scales
or
rust
On wet
walls
inside
the
engine
jackets
and
in
the
radiator
COre to interfere with smooth
heat
conduction.
Overheating
tendency of
u'e
engl.ne
is.
often
due
to ils
cooling water circuits
foul.d
with sc.le, sludge or rust
formation.
Fo
r
this
reason,
it
is
necessary
to
periodically
change
the
cooling
water
and
,
at
the
sam
e
time
,
flush
the
cooling system
clean
.
For
the
cooling
water]
be
sure
to
u," a soft water (drinking water
is
usually soft).
Woter pump services
(I)
Check to see
if
the bC1l'ing rattles
or
develops
hJtche,
when the pump shaft is
spun
by
hand; if it
does, replacement
is
necessary.
(2)
Inspect the
pump
ImpeUer for
pining,
erosi
on
and
breakage; replace
tl,.
inapeUe
r if it
is
found m bad
condition.
An
impelle
r
found
with its
front
or
rea
T
edges
sJ,owing
evidence
of
rubbing against pump
case
or
rear
cover
means
that
the
impeller together
with
th.
bearing need replacement.
Unit
seal
1·F
l
ost
i
(')ij
OeGl
~cil
rbon)
2&aJ ring
(~
rQ
mid
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