Yanmar 4JH45 Operation Manual page 92

TROUBLESHOOTING
Symptom
Breakdown of turbo-charger (If equipped)
Drop in intake pressure
Abnormal vibration
Noise
Quick contamination of engine
oil
Pulsation of intake air pressure
Other
Other malfunctions
Noise generation
86
Probable Cause
Dirty air filter
Leak from intake piping
Leak of exhaust gas
High intake air temperature
Drop in air pressure in engine room
Broken turbine impeller
Dirty turbine impeller
Clogged exhaust pipe
Broken turbine impeller
Broken compressor impeller
Deposit of carbon or oxides on turbine
Broken bearing
Bent turbine shaft
Loose parts or fasteners
Damaged bearing
Contact by revolving parts
Dirty or carbon deposit on turbine and
compressor
Entrapment of foreign matter (at
turbine entrance)
Rapid change in load (surging)
Gas trapped in bearing housing
Clogged seal air path
Damaged seal ring
Clogged pressure balance path
Uneven cylinder combustion
Rapid change in load
Excessively dirty compressor side
Intake temperature too high
Bearing seizure
Corrosion in compressor/turbine
impeller or bearing housing
Loose flywheel set bolts
Loose connecting rod bolts
Worn crank pin
Excessive gear backlash
Clean
Repair
Repair
Complete thermal insulation of exhaust pipe
Ensure intake air path is unrestricted from outside air
Clean air filter
Ensure intake air path is unrestricted from outside air
Replace
Clean
Clean
Replace
Replace
Remove and repair or replace
Replace
Replace
Tighten
Replace
Repair or replace
Clean
Repair or replace
Stabilize the load or replace turbine nozzle
Repair
Clean
Replace
Clean
Adjust for uniform combustion
Operate correctly
Clean
Clean cooling fin
Complete thermal insulation of exhaust pipe
Ensure intake air path is unrestricted from outside air
Replace
Increase the coolant temperature
Tighten bolts
Tighten bolts
Replace
Inspect the gear; replace worn gear, shaft, and/or
bushing with new ones
JH Series Operation Manual
Measure