TROUBLESHOOTING
Troubleshooting by Symptom
12/05
6LY3 Service Manual
13-5
© 2007 Yanmar Marine International
TROUBLESHOOTING BY SYMPTOM
It is important to thoroughly understand each system and the function of all parts in these systems. A careful
study of the engine mechanisms will make this possible. When problems arise, it is important to carefully
observe and analyze the indications of trouble in order to save time in determining their cause. Begin by
checking the most easily identifiable causes of difficulty. Where the cause of the difficulty is not readily
apparent, make a thorough examination of the system from the easiest, proceeding until the cause of the
trouble can be determined. While experience is an important factor in pinpointing engine problems, careful
study and understanding of the engine mechanisms, combined with good common sense, will help you
rapidly become an expert at troubleshooting.
Trouble Symptom
Causes
Corrective Action
Remarks
No power to the digital display
and the control head.
Low battery voltage / no battery
voltage.
Check the electrolyte level and
the specific gravity of the
battery liquid.
See Checking the Electrolyte
Level on page 12-4
.
Charge the battery or replace.
See Charging the Battery on
page 12-5
.
Check the wiring circuit.
See Alternator Wiring Diagram
on page 11-8
.
Battery will not charge.
Check the wires between the
alternator and the battery.
See Alternator Wiring Diagram
on page 11-8
.
Check the tension of the V-belt.
See Inspecting the Alternator
on page 11-9
.
Check the alternator.
See Alternator on page 11-1
.
Control system wiring is
disconnected.
Connect the control system
wires.
See Alternator Wiring Diagram
on page 11-8
.
Connectors are not closed.
Close the connectors
according to the manual.
See Remote Control Electronic
Control System (ECS) on
page 12-20
.
Contact failure of each
connector pin.
Check each connector pin and
confirm the continuity.
See Remote Control Electronic
Control System (ECS) on
page 12-20
.
Fuse burned out.
(AUX POWER: 10A)
Replace the fuse.
See Troubleshooting Fuses,
Relays and Harnesses on
page 13-21
.
Contrast control is too low
Adjust the contrast.
See Digital Display Operation
Manual.