COVER
DIAPHRAGM
ASSEMBLY-
71}
DIAPHRAGM
SPRING
—
VALVE
AND
CAGE
ASSEMBLIES
ROCKER
ARM
SPRING-
FILTER
SCREEN
ROCKER
nC
ARM
PIN
ROCKER
ARM-
BODY-
PRIMING
LEVER
A687
ROCKER
ARM
LINK
FILTER
BOWL
FIGURE
14.
FUEL TRANSFER
PUMP
Inspection:
To inspect the nozzle spray pattern remove
the nozzle
from
the cylinder head. Crank the engine,
let
the nozzle spray
into
the air and watch the pattern.
The spray should be cone shaped
with
a
solid
appearing
center surrounded by
cloudlike
fog
in
which
the spray is
evenly
atomized. See Figure 15. An apparent chattering
of
the nozzle is normal.
If
streamers
are
visible,
the pattern is badly distorted
or
the nozzle drips before it
reaches
opening
pressure,
it
is defective and must be cleaned or replaced.
WARNING
I
Do
not let the
nozzle spray against
your skin.
The
iuel
can
penetrate
flesh
and
cause
a
serious infection.
Adjustment:
To adjust the opening
pressure,
remove
the nozzle
from
the engine. Remove the cap nut over
the adjusting screw of the nozzle and
install
the noz-
zle
on a static
fuel
nozzle testing
fixture
(may be
purchased
from
Onan).
Following
the
tester
instruc-
tions,
adjust the opening
pressure
to
1750
psi by
turning
the adjusting screw. See Figure 16. Clockwise in-
creases
the
pressure
and counterclockwise
decreases
it.
Do not try to adjust the
pressure
without
a testing
fixture.
GOOD
if
m
POOR
SPRAY
J
|y\ SPRAY
PATTERN
;
V
PATTERN
•
:
m..
AOOT
**
Disassembly: When removing and disassembling noz-
zles,
separate
and label all nozzle components. Never
interchange components between nozzles.
1.
Remove nozzle assembly
from
the engine and
remove the
fuel
inlet
and return lines.
2.
Clamp the nozzle holder body in a vise and remove
the nozzle cap nut and nozzle.
3.
Install
the nozzle cap nut loosely to protect the
lapped surface for the holder body.
4.
If
necessary
to further disassemble the nozzle,
reverse the
pressure
adjusting screw and
lift
out
the spring and spindle assembly.
Cleaning:
The
most important part
of
nozzle cleaning
is
cleanliness.
Work
only
in a clean room, on a clean
work
bench. Keep
a pan of diesel
fuel
handy and have a supply of clean,
lint-free
wiping
rags.
IMPORTANT: Onan offers
a kit
to aid
nozzle cleaning.
See
Special Tools Section.
PRESSURE
ADJUSTING
SCREW—
GASKET
SPINDLE
'
ASSEMBLY
FUEL
INLET
•ROTECTION COVER
-PRESSURE
ADJUSTING SCREW
LOCK
NUT
^PRESSURE
ADJUSTING
SPRING
NOZZLE
CAP NUT;
NOZZLE GASKET
FUEL
CUP
GASKET
NOZZLE SHIELD
NOZZLE ASSY
CYLINDER—v
HEAD
\
P'NTLE
FIGURE
15.
NOZZLE SPRAY PATTERN
FIGURE
16.
NOZZLE ASSEMBLY
18
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