Yamaha 55DEHD Service Manual page 252

TRBL
SHTG
Symptom 1: Limited engine speed (below 2,000 r/min)
Symptom 2
9Buzzer comes
on (ED, ET)
9Overheat warn-
ing indicator
comes on (EHD)
9Cooling water
does not dis-
charge from the
cooling water
pilot hole
9-5
Troubleshooting
Cause 1
Clogged cooling water
inlet
Water pump
malfunction
Clogged cooling water
passage
Thermostat
malfunction
Thermoswitch
malfunction
Short connection in
thermoswitch circuit
and ground circuit
Cause 2
Check the cooling
—
water inlet.
Check the impeller.
Water pump
impeller
Check the Woodruff
malfunction
key.
Check the water pump
housing.
Water leakage
Check the insert car-
from water
tridge.
pump housing
Check the outer plate
cartridge.
Check the cooling
water passage
— (exhaust guide, upper
case and cooling water
pipe).
— Check the thermostat.
Check the
— thermoswitch for
continuity.
Check the wiring
—
harness for continuity.
Checking step
Refer
to
page
3-4
6-6
6-6
6-6
6-6
—
7-11
3-3
8-8
WD
6885J11