Delivery Valve Function
The delivery valve maintains
300
to
600
psi
(2070
to
4140 kPa) line pressure in the injector lines with the
engine running, Figure46. This pressure increases to
about
1900
psi
(13110
kPa) on each stroke of
the
injection pump plunger. The trapped fuel is held in
the lines at all times, even though the pressure bleeds
off during shutdown periods. When the lines are full
of fuel, only a couple turns of the crankshaft are
required to build up enough line pressure for firing
the injectors.
Code
16orS
15orR
14orP
13orN
12orM
SPRING
DELIVERY VALVE
/
PartNo.
Size Code
PartNo.
Size Code
PartNo.
Size
Inch
mm
Inch
mm
inch
mm
147-0186 .134
3.404
1
orA
147-0147
.119 3.023
6orF 147-0152 -101 2.565
147-0187
.131 3.357
2orB 147-0148
.116
2.946 7orH
147-0153 .098 2.489
147-0188 .128
3.251
3orC 147-0149
.113 2.870
8orI 147-0154
.095 2.413
147-0189
.125 3.175
4orD
147-0150
.110 2.794 9orK
147-0155 .092
2.337
147-0190 .122 3.099
5orE
147-0151
.lo7 2.718
10orL 147-0156
.089 2.261
11
orStd.
147-0161 .lo4 2.642
I
Preservative oil applied
to
the new
injection pump during assembiy may
cause the pump to stick. Forcing the plunger or gear
will damage the pump. Dissolve preservative by soak-
ing pump in clean filtered diesel fuel for
75
to
30
minutes.
TIMING BUTTON CODE
The timing button has a code number or letter
stamped on
it
that corresponds to its dimension in
thousandthsof an inch. SeeTable
8.
Figure47 shows
the timing button. One button will provide the correct
port closing.
.
SEAT
CODE LETTER
OR
NUMBER
STAMPED
ON
SIDE
LINE PRESSURE
FIGURE
46.
DELIVERY VALVE CLOSED -PLUNGER DOWN
Keeping the fuel system clean
is
extremely important.
A
fine particle
of dirt can ruin fhe injection system in a very short
time.
If
the fuel system is opened for any reason, cap
all openings and place the parts removed In clean
diesel fuel. Before installing new
or
used pads, wash
them in clean fuel and install them wet.
FIGURE
47.
TIMING
BUITON
CODE
TIMING BUTTON THICKNESS
Injection pump kits include a pump and four buttons
which will time most of the engines. The button and
retainer ring are not assembled.
The injection pump on each engine must be timed to
that engine by using a timing button of specific thick-
ness. Each new pump has its port closing dimension
stamped on the pump mountingflange.The portclos-
ing dimension is measured at the factory using a
number
11
or standard button.
Pump timing is critical. use one of the two timing
methods to determine correct new button thickness.
If the correct button
is
not supplied with the replace-
ment pump refer toTable
8
and order the correct one
from your Onan dealer.
TABLE
8.
TIMING
BUTTONS
Redistribution or publication of this document,
by any means, is strictly prohibited.
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