Yanmar 6LPA-STP2 Service Manual page 313

Troubleshooting Chart
12/05
Symptom
Abnormal exhaust color:
Fuel injection pump failure
Fuel injection valve failure
Turbocharger failure
Other
Insufficient output:
Insufficient fuel injection by
fuel injection pump
Insufficient injection by fuel
injection nozzle
6LPA Service Manual
Probable Cause
Faulty operation of plunger
Worn plunger
Faulty delivery valve
Uneven injection quantities
Improper injection timing
Clogged injection nozzle
Sticking needle valve
Reduction in injection pressure
Poor atomization
Carbon deposit
Clogged filter
Dirty compressor side
Clogged turbine side
Damaged bearing
Overload operation
Lubricant level too high
Accumulated carbon deposit at intake / exhaust valve
Dirty air cooler
Poor fuel quality
Clogged intake / exhaust valve
Worn plunger
Sticking plunger
Oil leak from delivery valve
Oil leak from fuel injection pipe joint
Faulty operation of regulator valve
Faulty position of governor lever
Clogged fuel filter
Clogged fuel pipe
Broken delivery valve spring
Faulty fuel feed pump
Clogged injection hole
Faulty valve seat
Sticking nozzle
Loose fuel injection pipe joint
Worn nozzle
© 2007 Yanmar Marine International
TROUBLESHOOTING
Measure
Disassemble and correct, or
replace
Replace
Disassemble and correct, or
replace
Re-adjust
Re-adjust
Replace
Replace
Re-adjust
Replace
Clean
Clean
Clean
Clean
Replace
Reduce load
Lower the oil level
Clean
Clean
Replace fuel
Clean
Replace
Overhaul or replace
Lap the valve
Tighten
Re-adjust
Re-adjust
Replace
Clean
Replace
Repair
Replace
Replace
Replace
Tighten
Replace
12-7