Yanmar 1GM User Manual page 153

FUEL I NJ ECTI ON AN D GOVERNOR SYST EMS 147
@
~Nut
~Retainer
plate
f!Ir-
Puellnjec tcr
o - - 0 -rIO g
o
Gasket
Heal s hield
~,}--- Co ppe r
gasket
~':I---
Precombustion chamber
0--
Copper gas ket
combustion byp rodu cts even tua lly affect inj ector opera-
tion. C logg ing may affect the sp ray pattern, which may
cause misfiring and decreased engine performance.
Yanma r docs nor speci fy when a fuel injector should be
removed for clea ning. A period ic ma intenan ce schedule
can
be formulated
based on when engine performance de-
cl ines due to the inj ec tor becoming clogged. An injector
should pcrfonn properly for several hundred hours before
requiring service; otherw ise, operating proced ures. fuel
type or cond ition . or another cngine problem are responsi-
ble for unsat isfacto ry injec tor operation .
Injector service
should be limited to
removal for exter-
nal cleaning. Have a Yanmar dealership or diesel fuel in-
j ec tion shop pcrfonn internal cleaning or ov erhaul.
Rem oval a nd Installation
Refer to Figure 23 for an exploded view of the fuel in-
jector and preco mbustion chambe r assembly.
I . Th orou ghl y clean the fue l injector and the area around
the inj ec tor to make sure debris will not fall into the en-
gmc.
NOTE
Plug or cap all fuel openings
10
prevent the
enlranc e ofdin or debris.
NOTE
Note the location ofall washers so they can
he returned to their original positions.
2. Detach the fuel return line from the nipple on the fue l
inj ector. On mulricylin dcr engines, the fuel return line
must be removed from all injec tors. Hold the injector and
remove the fuel return line nut (A, Figure 24) and return
line fitting .
3. If necessary, unscrew the fuel line retaining brac kets.
Detach the high-p ressu re fue l line (8, Figure 24) from the
fuel inj ector.
4 . Unscrew the retainer plate nuts (A, Figure 25), then
remo ve the retain er plate (8).
5. Remo ve the fuel injector (F igu re 26).
6, Extract the heat shield and gas ket (f igu re 27). The
gas ket resides in a groo ve in the to p of the heat shield.
NOTE
Do not damage the precombustion chamber
when removing it in Step 7
if
it is tight in the
cylinder head.
If
necessary. remove the cyl-
inder head to dislodge the precombustion
chamber.
7