Yanmar 3TNV Series, Service Manual

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3. Troubleshooting
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
Engi
ne do
es n
ot start.
None Little Much Ordinary Wh
ite
Black Wh
ite
Black High knocking sound during
combustion
Abnorm
al en
gi
ne sou
nd
Uneve
n comb
u
stion sou
nd
Durin
g idl
ing
Durin
g work
Larg
e eng
ine v
ibratio
n
Difficulty in ret
urnin
g to low s
pee
d
Excessive fue
l consum
ption
Excessive consumption Diluti
on by fue
l oil
Mixture with w
ater
Low L.O. pressure Much bl
ow-by
gas
Overheat Low wat
er temperatur
e
Pressure dr
op
Pressure rise Exhaust tempe
rature rise
Corrective action
Excessive cooling effect of radiator Defective thermostat (kept closed) (See 2.2.7 in Chapter2.)
Insufficient cooling effect of radiator
Defective thermostat (kept opened)(See 2.2.7 in Chapter2.)
or slipping fan belt (See 2.2.2-2) in Chapter2.)
Insufficient coolant water level
Check water leakage from cooling water system.
(See 2.2.1-4) in Chapter2.)
Cracked water jacket Repair or replace.
Slackened fan belt Adjust the belt tension. (See 2.2.2-2) in Chapter2.)
Defective thermostat Check or replace. (See 2.2.7 in Chapter2.)
Cool
ing W
ater
System
Improper properties of lubricating oil Use proper lubricating oil. (See 1.3.2 in Chapter1.)
Leakage from lubricating oil piping system r. Repai
Insufficient delivery capacity of trochoid pump Check and repair. (See 5.5 in Chapter5.)
Clogged lubricating oil filter Clean or replace.
Defective pressure regulating valve Clean, adjust or replace.
Insufficient lubricating oil level Add proper lubricating oil. (See 2.2.1-3) in Chapter2.) Lubric
atin
g System
Too early timing of fuel injection pump Check and adjust. (See 2.2.7-4) in Chapter2.)
Too late timing of fuel injection pump Check and adjust. (See 2.2.7-4) in Chapter2.)
Improper properties of fuel oil Use proper fuel oil. (See 1.3.1 in Chapter1.)
Water entrance in fuel system Perform draining from the fuel filter. (See 2.2.3 and 2.2.5 in Chapter2.)
Clogged fuel filter Clean or replace. (See 2.2.5 in Chapter2.)
Air entrance in fuel system .) Perform air bleeding. (See 2.2.3 in Chapter2
Clogged or cracked fuel pipe e. Clean or replac
Insufficient fuel supply to fuel injection pump Check the fuel tank cock, fuel filter, fuel pipe, and fuel feed pump.
Uneven injection volume of fuel injection pump Check and adjust.
Excessive fuel injection volume Check and adjust.
Poor spray pattern from fuel injection nozzle Check and adjust. (See 2.2.6 in Chapter2.)
Priming failure
Foreign matter trapped in the valve inside the priming pump.
(Disassemble and clean.)
Clogged strainer at feed pump inlet r. Clean the straine
Fuel system
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