Yanmar 6LY3 series - Page 313

TROUBLESHOOTING
Troubleshooting Fuses, Relays and Harnesses
12/05
6LY3 Service Manual
13-23
© 2007 Yanmar Marine International
6 250A Air heater “A”
or “B”
As air heater “A” is
not turned on, the
startability of the
engine in low
temperature
becomes worse.
With the air heater
off, the engine is
hard to start.
As air heater “A” is not
turned on, the white
smoke may increase
when the engine is
cold. With the air
heater off, white
smoke increases
when cold.
Off Check the air heater. If it is OK, check the
operation of the air heater relay. If it has
failed, replace it.
On Check the operation of the air heater relay.
If it is OK, check it for continuity. If it has
failed, replace the air heater relay.
Off Check the continuity between the negative
(-) side of the fuse and ground. (See Wire
Harness Locations on page 12-18.) In case
of continuity, harness (B) may have a short
circuit. Replace it. (See Wire Harness
Locations on page 12-18.) In case of no
continuity, remove the harness from the air
heater terminal and check continuity
between the harness and ground. In case of
continuity, main harness may have a short
circuit. Replace it. In case of no continuity,
replace the fuse. If the fuse burns out again,
the main harness may have a short circuit.
Replace it.
7 150A ALTERNATOR Engine runs normal. Engine runs normal.
Battery discharge.
Off Check the continuity between the negative
(-) side of the fuse and ground. (See Wire
Harness Locations on page 12-18.) In case
of continuity, harness (A) may have a short
circuit. Replace it. (See Wire Harness
Locations on page 12-18.) In case of no
continuity, replace the fuse and follow it. If
the fuse burns out again, the main harness
may have a short circuit. Replace it.
8 50A STARTER
RELAY
Engine will not start.
With the starter
switch on, relay
snaps but engine
will not turn over.
Speed sensor error
is detected.
Battery discharge. Off Check the continuity between the negative
(-) side of the fuse and ground. (See Wire
Harness Locations on page 12-18.) In case
of continuity, check the starter relay. In case
of no continuity, replace the fuse. If the fuse
burns out again, check the starter relay.
On Check the operation of the starter relay. If it
is OK, harness (F) may have a short circuit.
Replace it (See Wire Harness Locations on
page 12-18.). If it has failed, the relay may
be damaged and the harness (c) is shorted.
Replace them both. In case the fuse burns
out again, replace starter.
No. Size Application
Trouble Symptom
Key
Switch
Corrective Action
Engine Stop Engine Running