Yanmar 3JH4E Service Manual page 62

TROUBLE AND TROUBLESHOOTING
(I-1) Bleed air.
(I-2) Disassemble and clean.
(I-3) Replace.
(I-4) Repair or replace.
(I-5) Replace.
(I-6) Tighten firmly.
(I) Uneven quantity of fuel oil injected
(1) Air in the fuel injection pump
(2) Faulty operation of plunger
(3) Damaged plunger spring
(4) Faulty fuel oil ejection valve
(1) Oil leakage in injection
system
(2) Damaged valve
spring
(5) Sticking of injection valves
(3) Insufficient injection
pressure in injection
valves
(II) Faulty fuel injection valve
(II-1) Check and repair.
(II-2) Replace.
(II-3) Adjust.
(II-4) Adjust.
(II-5) Clean.
Chart 2
CYLINDER OUTPUT IS UNEVEN COUNTERMEASURE
(I -7) Disassemble and clean
and repair replace.
(5) Damaged exhaust union packing
(6) Loose pinion screw
(7) Faulty fuel injection
pump tappet
CYLINDER OUTPUT
IS UNEVEN
(4) Irregular injection timing
Trouble and Troubleshooting
(I-1) Check, repair or replace.
(I-2) Replace.
(I-3) Check, repair or replace.
(I-4) Adjust.
(I-5) Adjust.
(I) Faulty fuel injection pump
(1) Faulty plunger operation
(1) Injection opening is clogged
(2) Worn plunger (2) Sticking of valve needle
(3) Low injection pressure
(3) Faulty ejection valve
(4) Uneven quantity of fuel injected
(4) Faulty spry condition
(5) Irregular fuel injection timing (5) Carbon deposit
(1) Clogged filter
(1) Overloading
(2) Too great a quantity of lube oil
(3) Carbon deposit in suction valves
(4) Dirty air cooler
(5) Poor quality fuel oil
(6) Clogging in exhaust system Cause
(III) Clogged intake air filter
(III-1) Clean.
Chart 3
POOR EXHAUST COLOR
(II-1) Clean.
(II-2) Check, repair or replace.
(II-3) Adjust.
(II-4) Check, repair or replace.
(II-5) Clean.
(II) Faulty fuel injection valve
POOR
EXHAUST
COLOR
(IV) Miscellaneous
(IV-1) Reduce load.
(IV-2) Adjust quantity of oil.
(IV-3) Clean.
(IV-4) Clean.
(IV-5) Reduce. with new oil.
(IV-6) Clean.