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