Yamaha F150A Service Manual page 125

Symptom 1: High engine idle speed
Symptom 2
—
Symptom 1: Limited engine speed
Symptom 2
Buzzer comes on, over-
heat alert indicator
comes on
Buzzer comes on, oil
pressure alert indicator
comes on
—
Cause
Air leakage (throttle valve–cyl-
inder head)
Throttle link and throttle cable
are not installed properly.
ISC valve malfunction
Cause
Clogged cooling water inlet
Water pump impeller malfunc-
tion
Water leakage from water
pump housing
Clogged cooling water pas-
sages
PCV is open.
Thermostat malfunction
Insufficient engine oil
Engine oil pressure decrease
Y-COP malfunction
Outboard motor troubleshooting
Checking steps
Check the gaskets of the intake manifold
and throttle body.
Check the intake manifold for cracks.
Adjust the throttle link and throttle cable.
Check the ISC valve operation using the
YDIS.
Measure the ISC valve input voltage.
Checking steps
Check the pilot hole for cooling water dis-
charge.
Check the cooling water inlet.
Check the impeller.
Check the Woodruff key.
Check the insert cartridge.
Check the water pump housing.
Check the outer plate cartridge.
Check the cooling water passages.
Check the PCV.
Check the thermostat.
Check the oil level.
Check for engine oil leakage.
Check the valve seals and valves.
Check the piston rings.
Measure the oil pressure.
Check the oil pressure sensor.
Check the oil pump.
Check the oil strainer.
Check the oil passages (power unit and
oil pump).
Replace the oil filter.
Check Y-COP for wiring harness continu-
ity.
4-14
See
page
6-34
6-38
3-11
6-27
5-15
5-15
See
page
10-5
10-8
8-11
8-11
8-11
8-11
8-11
2-16
7-50
7-50
10-5
2-15
7-41
7-43
7-64
7-1
5-16
7-54
9-22
2-15
7-56
5-30