TROUBLESHOOTING
PUMP
PROBLEMS
Normally, little goes wrong with the injection pump
after
it
is installed on the engine as long
as
timing
is
correct and clean fuel is used continually.
The
most
common problem is caused
by
a
delivery
valve that may be held open by dirt or metal chipsthat
entered the pump
or
fuel system during assembly and
installation.That is the reason protectivecovers must
be used to keep foreign matter out of unassembled
fuel system components.
If the pump is suspected
of causing misfires or poor
operation:
0
Check the temperature of each nozzle holder and
exhaust port; the coolest cylinder is the faulty
one.
Fuel penefration
of
the skin
might cause severe personal
injury.
Do
not
let the nozzle high-pressure fuel
spray
against skin
surfaces.
Loosen (crack) the high pressure injection lines,
one cylinder at a time (like disconnecting a spark
plug wire), to determine the faulty cylinder; the
cylinder that looses the least power is misfiring,
or not firing.
Pump disassembly
by
unqualified personnel
is
not authorized
and may void the pump warranty.
Return all faulty pumps
to
the Onan factory for repairs, or
replacement
if
still
under
warranty.
Otherwise,
refer all Ser-
vice
problems
to
authorized
B~yceRucas
and
Diesel
Kiki
ser-
vice centers.
THROTTLING PINTLE NOZZLE TESTS
The following tests will determine nozzle conditions
using a manually operated test stand. Each nozzle
must be removed from the engine for testing. Prior to
testing, each nozzle must be cleaned, decarboned,
and inspected, as described for non- throttling pintle
type nozzles earlier
in
this section. New or recondi-
tioned nozzles must be thoroughly cleaned in cleaning
solvent or test oil to remove
all
traces of preservative
grease before testing.
Visual
Check
Using illuminated Magnifier:
1.
Inspect nozzle valve for damaged
or
rough seat.
2.
Inspect pintle for wear, damage, or out-of-round
3.
Check nozzle body for damaged or carboned
spray hole.
seat.
Slide
Test
oil.
1.
Dip clean nozzle valve
in
filtered diesel fuel or test
2.
Insert valve in nozzle body, Figure
67
3.
Holding body almost vertically, puli valve out to
one-third of its engaged length; then release
valve.
4.
The released valve (becauseof its weight) should
slide down to its seat.
The nozzle valve and nozzle
body
are
lapfitted
together and must
not
be
interchanged.
57
Redistribution or publication of this document,
by any means, is strictly prohibited.
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