TROUBLESHOOTING
Troubleshooting by Symptom
13-18
6LY3 Service Manual
© 2007 Yanmar Marine International
White exhaust smoke from warm engine.
Faulty fuel injection nozzle.
Faulty valve and / or seat.
Check the fuel spray
condition with a tester. If a
malfunction is found, send to
an FIE shop for service or
replacement.
See Fuel Injection Nozzle
Components and Functions
on page 6-26
.
Sticking needle valve.
Wear of the seat.
Clogged fuel injection
hole(s).
Decrease in fuel opening
pressure.
Improper fuel.
Low cetane number.
Replace fuel.
See Fuel Selection on
page 3-6
.
Excessive aromatics in the
fuel.
Replace fuel.
See Fuel Selection on
page 3-6
.
Excessive amount of oil in
the engine causing oil to
burn.
Seized piston.
Disassemble and check.
Replace if necessary.
See Inspecting the Pistons
and Piston Pins on
page 5-36
.
Wear of the piston rings.
Check and replace.
See Measuring the Pistons
on page 5-37
.
Sticking piston rings.
Check, clean and replace.
See Measuring the Pistons
on page 5-37
.
Scarring or wear of the
cylinder wall.
Disassemble and check.
Repair or replace if
necessary.
See Inspecting the Cylinder
Block and Components on
page 5-22
.
Insufficient amount of oil in
the engine causing oil to
burn.
Scarring or wear of the
intake / exhaust valves.
Disassemble, check and
measure the dimension.
Repair or replace if
necessary.
See Inspecting Intake /
Exhaust Valves and Valve
Guides on page 5-30
.
Scarring or wear of the valve
guides.
Disassemble, check and
measure the dimension.
Repair or replace if
necessary.
See Inspecting Intake /
Exhaust Valves and Valve
Guides on page 5-30
.
Damaged stem seal.
Replace if necessary.
See Inspecting the Valve
Stem Seals on page 5-32
.
Trouble symptom
Causes
Corrective action
Remarks