Yanmar 6LPA-STP2 Service Manual page 314

TROUBLESHOOTING
Symptom
Governor failure
Compressed gas leak in the
engine cylinder
Improper fuel injection timing
Turbocharger failure
Other
Output for each cylinder is not uniform:
Uneven fuel injection
quantities
Failure of fuel injection nozzle
Knocking:
Fuel injection nozzle failure
Fuel injection pump failure
12-8
Probable Cause
Damaged governor bearing
Improper length of governor link
Gas leak from intake / exhaust valve
Valve clearance too small
Worn upper portion of cylinder bore
Worn piston ring
Sticking piston ring
Injection timing too advanced
Injection timing too retarded
Clogged air filter
Dirty compressor side
Clogged turbine nozzle
Damaged bearing
Improper fuel
Clogged exhaust duct
Seized or overheated moving parts
Insufficient seawater
Insufficient feed of lubrication oil
Air trapped in fuel injection pump
Faulty operation of plunger
Broken plunger spring
Faulty delivery valve
Damaged delivery valve gasket
Faulty operation of regulator valve
Faulty operation of fuel injection pump timer
Oil leak from fuel injection system
Broken valve spring
Uneven injection pressures of injection valves
Improper injection timing
Clogged injection valve
Reduction in injection pressure
Broken fuel valve spring
Sticking nozzle
Poor spray pattern
Faulty operation of fuel injection pump timer
Faulty operation of regulator valve
© 2007 Yanmar Marine International
Troubleshooting Chart
Measure
Replace
Correct
Conduct fitting of the valve
Re-adjust
Lap or replace
Replace
Overhaul or replace
Retard the injection timing
Advance the injection timing
Clean
Clean
Clean
Replace
Replace with correct fuel
Clean
Disassemble and conduct
servicing
Inspect seawater pump
Disassemble and clean
lubrication oil pump and filter
Bleed
Disassemble and clean
Replace
Repair or replace
Replace
Overhaul or replace
Overhaul or replace
Inspect and repair
Replace
Re-adjust
Re-adjust
Clean
Adjust for higher injection
pressure
Replace
Disassemble and lap
Overhaul
Repair
Repair
6LPA Service Manual