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3.2 Quick Reference Table for Troubleshooting
The following table summarizes the general trouble symptoms and their causes. If any trouble symptom occurs, take corrective action before it becomes a serious problem so as not to shorten the engine service life.
Starting failure
Insufficient
engine output
Poor
exhaust
color
Hunting
Lubricating oil
Cooling
water
Air
intake
Engine starts
but stops
soon.
Exhaust
color
During
work
Exhaust
smoke
Trouble symptom
Cause
Engine
doe
s n
o
t start.
N
one
Littl
e
Muc
h
Ord
in
a
ry
White
Blac
k
White
Blac
k
H
igh knocki
ng soun
d during com
bust
ion
Abnorm
al e
ngi
ne
soun
d
U
neven
co
mb
usti
on
sou
n
d
Du
ri
n
g
id
lin
g
Du
ri
n
g
wo
rk
Large eng
ine vibr
atio
n
Diffic
u
lty in
retur
n
in
g to
low s
pee
d
E
xc
es
si
ve f
u
el
co
n
su
m
pt
io
n
E
xce
ss
ive
co
nsu
m
pt
ion
Diluti
on b
y fu
el o
il
M
ixtu
re
wi
th
wa
te
r
Low
L.O
. pr
es
sure
Muc
h
bl
ow
-by
ga
s
O
verheat
Low
w
a
ter t
e
m
perat
ure
Press
u
re dr
op
Pres
su
re ri
se
Exhau
st t
e
mp
eratur
e ri
se
Corrective action
Improper clearance of intake/exhaust valve
Adjust the valve clearance. (See 2.2.6 in Chapter2.)
Compression leakage from valve seat
Lap the valve seat. (See 4.2.6 in Chapter4.)
Seizure of intake/exhaust valve
Correct or replace.
Blowout from cylinder head gasket
Replace the gasket. (See 4.2.2-11) in Chapter4.)
Seized or broken piston ring
Replace the piston ring. (See 4.2.2-5)10) in Chapter4.)
Worn piston ring, piston or cylinder
Perform honing and use oversize parts.
(See 4.4.5-1)4) and 4.4.6 in Chapter4.)
Seized crankpin metal or bearing
Repair or replace.
Improper arrangement of piston ring joints
Correct the ring joint positions. (See 4.4.4-6 in Chapter4.)
Reverse assembly of piston rings
Reassemble correctly. (See 4.4.4-6 in Chapter4.)
Worn crankpin and journal bearing
Measure and replace. (See 4.4.5-2) in Chapter4.)
Loosened connecting rod bolt
Tighten to the specified torque. (See 4.4.4-2 in Chapter4.)
Foreign matter trapped in combustion chamber
Disassemble and repair.
Excessive gear backlash
Adjust gear meshing. (See 4.3.4-2 in Chapter4.)
Worn intake/exhaust valve guide
Measure and replace. (See 4.2.5-2) and 4.2.7 in Chapter4.)
Defective governor
Make adjustment.
Improper open/close timing of intake/exhaust valves
Adjust the valve clearance. (See 2.2.6-3) in Chapter2.)
Engine
s
yst
em
Fouled blower
Wash the blower.
Waste gate malfunction
Disassemble and inspect.
Worn floating bearing
Disassemble and inspect.
T
u
rb
oc
h
a
rge
r
