
TROUBLESHOOTING CHART
Symptom
Probable Cause
Measure
Reference
Alarm indicators and
alarm sound come on in
the display during oper-
ation.
Shift to low speed operation immediately, and check which indicator has come on in the display.
Stop the engine for inspection. If no abnormality is identified and there is no problem with oper-
ation, return to the port at lowest speed and request repairs.
• Lube oil low pressure
alarm indicator comes
on.
• Engine lube oil level is low.
• Check lube oil level. Add
or replace.
Checking Engine Oil on
page 28.
• Lube oil filter clogged.
• Replace lube oil filter.
Replace lube oil.
Replace Engine Oil and
Engine Oil Filter on
page 52.
• Marine gear lube oil
pressure alarm indicator
comes on.
• Marine gear lube oil is low.
• Check the oil level and
supply.
—
• Coolant high tempera-
ture alarm indicator
comes on.
• Coolant / fresh water in coolant
tank is low.
• Check coolant level and
replenish.
Check Diesel Fuel, En-
gine Oil and Engine
Coolant Levels on page
50.
• Insufficient seawater causing tem-
perature to rise.
• Check seawater system.
—
• Contamination inside cooling sys-
tem.
• See your authorized
Yanmar Marine dealer or
distributor.
—
Faulty Warning Devices
Do not operate the engine if alarm devices are not repaired. Serious accidents may result if
difficulties are not spotted due to faulty alarm lamps.
(1) When switch is turned ON:
• Alarm buzzer sounds.
• Circuit broken.
Note: Alarm buzzer only sounds
when there is an abnormality.
• See your authorized
Yanmar Marine dealer or
distributors.
—
• Alarm indicator comes
on.
• Circuit broken.
Note: Alarm indicator only comes on
when there is an abnormality.
• See your authorized
Yanmar Marine dealer or
distributor.
—
(2) When the rocker switch returned to ON from START after engine starts:
• Buzzer keeps on sound-
ing.
• Sensor switches faulty
(if indicator comes on).
• Short-circuit
(if indicator does not come on).
• See your authorized
Yanmar Marine dealer or
distributor.
—
• One of the alarm indica-
tors comes on.
• Sensor switches engine faulty.
• See your authorized
Yanmar Marine dealer or
distributor.
—
• Battery low charge indi-
cator comes on during
operation.
• V-belt is loose or broken.
• Replace V-belt; adjust
tension.
Adjust Alternator V-Belt
Tension on page 56.
• Battery defective.
• Check battery fluid level,
specific gravity. Re-
place.
Check the Battery on
page 55.
• Alternator power generation fail-
ure.
• See your authorized
Yanmar Marine dealer or
distributor.
—
• DC-DC Converter failure.
• See your authorized
Yanmar Marine dealer or
distributor.
—
White Exhaust Smoke at
Start
• Poor fuel quality.
• Replace with fresh fuel.
—
Black Smoke on Accel-
eration
• Propeller too large.
• Hull bottom dirty.
• Replace with correct
size.
• Clean hull bottom.
—
TROUBLESHOOTING
6LY3 LDC Operation Manual
67
© 2008 Yanmar Marine International