Yanmar 1GM User Manual page 39

TROUBLESHOOTING
CURRENT OUTPUT TEST
35A ALTERNATOR
Battery cable
33
z
5 5 A ALTERNATOR
Ammeter
Batt ery cable
,VOTE
If
the fuel injection pump or a fuel injector is
suspected. haw' it checked by a diesel en-
gine service shop before purchasing re-
placement parts.
When troubleshooting the fuel system. refer to the fol-
low ing symptoms and po ssib le causes:
1. Engine
will
not slart-ehcck for an empty fuel lank,
incorrect fuel or wat er in the fue l. Bleed the fuel system as
descr ibed in Chapter Seven
to be sure
that fue l is rout ed to
the fuel injection pump and to locate any restriction s. such
as the fuel filter, or defective components, such as the fue l
transfer pump. Check for proper operation and adjustment
of the speed control mechanism. includi ng the stop lever.
Refer to Chapter Seven. Check the fuel injection timing as
directed in Chapter Seven.
2. Engine slops suddenly-Chcck
for an empty fuel tank,
incorrect fuel or watcr in the fuel. Bleed the fuel systc m as
directed in Chapter Seven to be sure that fuel is ro uted to
the fuel inj ection pump and to locate any restrictions, such
as the fuel filter, or defective components, such as the fue l
trans fer pump. Check for thc proper operation and adju st.
rnent o f the speed control mechanism , including the stop
lever.
3. Engine speed decreases unexpectedly--Check
for wa-
tcr in the fuel . Ch eck for a clogged fuel filter element.
Bleed the fuel sys tem as described in Chapter Seven to
reo
move air in the fuel. Chec k for clogged or defecti ve fuel
injectio n pump or fue l injector.
4. Engine will not ru n under fu ll load-e heck for a
clogged fue l filter elem ent . Check for a defective fucl
tran sfer pump. Check for a clogged or defective fuel in-
jection pump. Check the speed con trol mec hanism.
5. Engine misfires-Check
for water in the fue l. Chec k
for a clogged fue l filte r clement. Bleed the fue l system as