Yamaha F150 Four Stroke Manual

							Maintenance
54
7. Dispose of used oil according to local
regulations.
NOTE:

For more information on the disposal of
used oil, consult your Yamaha dealer.

Change the oil more often when operating
the engine under adverse conditions such
as extended trolling.
EMU29112Checking wiring and connectors

Check that each grounding wire is properly
secured.

Check that each connector is engaged se-
curely.
EMU29120Exhaust leakage
Start the engine and check that no exhaust
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder.
EMU29130Water leakage
Start the engine and check that no water
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder.
EMU29140Engine oil leakage
Check for oil leaks on the around the engine.
NOTE:
If any leaks are found, consult your Yamaha
dealer.
EMU29153Checking power trim and tilt system
WARNING
EWM00430

Never get under the lower unit while it is
tilted, even when the tilt support lever is
locked. Severe injury could occur if the
outboard motor accidentally falls.

Make sure no one is under the outboard
motor before performing this test.
1. Check the power trim and tilt unit for any
sign of oil leaks.
2. Operate each of the power trim and tilt
switches on the remote control and en-
gine bottom cowling (if equipped) to
check that all switches work.
3. Tilt the outboard motor up and check that
the tilt rod and trim rods are extended
completely.
4. Use the tilt support lever to lock the motor
in the up position. Operate the tilt down
switch briefly so the motor is supported
by the tilt support lever.
1. Oil dipstick
2. Lower level mark
3. Upper level mark
1. Tilt rod
2. Tilt support lever
3. Trim rods
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							Maintenance
55
5. Check that the tilt rod and trim rods are
free of corrosion or other flaws.
6. Activate the tilt-down switch until the trim
rods have retracted completely into the
cylinders.
7. Activate the trim-up switch until the tilt rod
is fully extended. Unlock the tilt support
lever.
8. Tilt the outboard motor down. Check that
the tilt rod and trim rods operate smooth-
ly.
NOTE:
Consult your Yamaha dealer if any operation
is abnormal.
EMU29171Checking propeller
WARNING
EWM00321
You could be seriously injured if the en-
gine accidentally starts when you are near
the propeller.

Before inspecting, removing, or install-
ing the propeller, remove the spark plug
caps from the spark plugs. Also, place
the shift control in neutral, turn the main
switch to “” (off) and remove the key,
and remove the lanyard from the engine
stop switch. Turn off the battery cut-off
switch if your boat has one.

Do not use your hand to hold the propel-
ler when loosening or tightening the
propeller nut. Put a wood block between
the anti-cavitation plate and the propel-
ler to prevent the propeller from turning.
Checkpoints

Check each of the propeller blades for
wear, erosion from cavitation or ventilation,
or other damage.

Check the propeller shaft for damage.

Check the splines / shear pin for wear or
damage.

Check for fish line tangled around the pro-
peller shaft.
ZMU01897
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							Maintenance
56

Check the propeller shaft oil seal for dam-
age.
NOTE:
If the shear pin equipped: it is designed to
break if the propeller hits a hard underwater
obstacle to help protect the propeller and
drive mechanism. The propeller will then spin
freely on the shaft. If this happens, the shear
pin must be replaced.
EMU30660Removing the propellerEMU29194Spline models
1. Straighten the cotter pin and pull it out us-
ing a pair of pliers.
2. Remove the propeller nut, washer, and
spacer (if equipped).3. Remove the propeller and thrust washer.
EMU30670Installing the PropellerEMU29241Spline models
WARNING
EWM00770
On counter rotation models, be sure to
use a propeller intended for counterclock-
wise rotation. These propellers are identi-
fied with the letter “L” after the size
indication on the propeller. Otherwise the
boat could move in the opposite direction
from that expected.
CAUTION:
ECM00340

Be sure to install the thrust washer be-
fore installing the propeller, otherwise
the lower case and propeller boss could
be damaged.

Be sure to use a new cotter pin and bend
the ends over securely. Otherwise the
propeller could come off during opera-
tion and be lost.
1. Apply Yamaha marine grease or a corro-
sion resistant grease to the propeller
shaft.
2. Install the thrust washer and propeller on
the propeller shaft.
3. Install the spacer and washer. Tighten
the propeller nut to the specified torque.
4. Align the propeller nut with the propeller
shaft hole. Insert a new cotter pin in the
hole and bend the cotter pin ends.
1. Cotter pin
2. Propeller nut
3. Washer
4. Spacer
5. Propeller
6. Thrust washer
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							Maintenance
57
NOTE:
If the propeller nut does not align with the pro-
peller shaft hole after tightening to the speci-
fied torque, tighten the nut further to align it
with the hole.
EMU29281Changing gear oil
WARNING
EWM00800

Be sure the outboard motor is securely
fastened to the transom or a stable
stand. You could be severely injured if
the outboard motor falls on you.

Never get under the lower unit while it is
tilted, even when the tilt support lever or
knob is locked. Severe injury could oc-
cur if the outboard motor accidentally
falls.
1. Tilt the outboard motor so that the gear oil
drain screw is at the lowest point possi-
ble.
2. Place a suitable container under the gear
case.
3. Remove the gear oil drain screw.
NOTE:
If the magnetic gear oil drain screw equipped:
remove all metal particles from the screw be-
fore installing it.
4. Remove the oil level plug to allow the oil
to drain completely.
CAUTION:
ECM00710
Inspect the used oil after it has been
drained. If the oil is milky, water is getting
into the gear case which can cause gear
damage. Consult a Yamaha dealer for re-
pair of the lower unit seals.
NOTE:
For disposal of used oil consult your Yamaha
dealer.
5. With the outboard motor in a vertical po-
sition, and using a flexible or pressurized
filling device, inject the gear oil into the
gear oil drain screw hole.
1. Gear oil drain screw
2. Oil level plug
Recommended gear oil:
Hypoid gear oil SAE#90
Gear oil quantity:
F150TR 980.0 cm³ (33.13 US oz) 
(34.56 Imp.oz)
 LF150TR 870.0 cm³ (29.41 US oz) 
(30.68 Imp.oz)
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							Maintenance
58
6. When the oil begins to flow out of the oil
level plug hole, insert and tighten the oil
level plug.
7. Insert and tighten the gear oil drain
screw.
EMU29312Inspecting and replacing anode(s)
Yamaha outboard motors are protected from
corrosion by sacrificial anodes. Inspect the
external anodes periodically. Remove scales
from the surfaces of the anodes. Consult a
Yamaha dealer for replacement of external
anodes.
CAUTION:
ECM00720
Do not paint anodes, as this would render
them ineffective.
NOTE:
Inspect ground leads attached to external an-
odes on equipped models. Consult a Yamaha
dealer for inspection and replacement of inter-
nal anodes attached to the power unit.
EMU29320Checking battery (for electric start 
models)
WARNING
EWM00330
Battery electrolytic fluid is dangerous; it
contains sulfuric acid and therefore is poi-
sonous and highly caustic.
Always follow these preventive measures:

Avoid bodily contact with electrolytic
fluid as it can cause severe burns or per-
manent eye injury.

Wear protective eye gear when handling
or working near batteries.
Antidote (EXTERNAL):

SKIN - Flush with water.

EYES - Flush with water for 15 minutes
and get immediate medical attention.
Antidote (INTERNAL):
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							Maintenance
59

Drink large quantities of water or milk
followed by milk of magnesia, beaten
egg, or vegetable oil. Get immediate
medical attention.
Batteries also generate explosive hydro-
gen gas; therefore, you should always fol-
low these preventive measures:

Charge batteries in a well-ventilated ar-
ea.

Keep batteries away from fire, sparks, or
open flames (for example: welding
equipment, lighted cigarettes, and so
on.)

DO NOT SMOKE when charging or han-
dling batteries.
KEEP BATTERIES AND ELECTROLYTIC
FLUID OUT OF REACH OF CHILDREN.
CAUTION:
ECM00360

A poorly maintained battery will quickly
deteriorate.

Ordinary tap water contains minerals
harmful to a battery, and should not be
used for topping up.
1. Check the electrolyte level at least once a
month. Fill to the manufacturer’s recom-
mended level when necessary. Top up
only with distilled water (or pure de-ion-
ized water suitable to use in batteries).2. Always keep the battery in a good state of
charge. Installing a voltmeter will help
you monitor your battery. If you will not
use the boat for a month or more, remove
the battery from the boat and store it in a
cool, dark place. Completely recharge
the battery before using it.
3. If the battery will be stored for longer than
a month, check the specific gravity of the
fluid at least once a month and recharge
the battery when it is low.
NOTE:
Consult a Yamaha dealer when charging or
re-charging batteries.
EMU30051Connecting the battery
WARNING
EWM00570
Mount the battery holder securely in a dry,
well-ventilated, vibration-free location in
the boat. Install a fully charged battery in
the holder.
CAUTION:
ECM01121

Make sure the main switch (on applica-
ble models) is “” (off) before working
on the battery.

Reversal of the battery cables will dam-
age the electrical parts.

Connect the red battery cable first when
installing the battery and disconnect the
black battery cable first when removing
it. Otherwise, the electrical parts can be
damaged.

The electrical contacts of the battery
and cables must be clean and properly
connected, or the battery will not start
the engine.
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							Maintenance
60
Connect the RED battery cable to the POSI-
TIVE (+) terminal first. Then connect the
BLACK battery cable to the NEGATIVE (-) ter-
minal.
Connecting an accessory battery (optional)
1. Remove the accessory battery coupler
cover from the outboard motor.
2. Connect the accessory battery coupler to
the coupler of the accessory battery ca-
ble (optional). Use a connecting cable be-
tween the (-) terminals of the starting
battery and accessory battery. See the il-
lustrations of the wiring connections. This
cable must be made from wire thicker
than the starting battery cable.
WARNING
EWM00600
Use of smaller wire could lead to a fire.
NOTE:
If connecting an accessory battery, consult
your Yamaha dealer about correct wiring.
EMU29370Disconnecting the battery
Disconnect the BLACK cable from the NEGA-
TIVE (-) terminal first. Then disconnect the
RED cable from the POSITIVE (+) terminal.
EMU29390Checking top cowling
Check the fitting of the top cowling by pushing
it with both hands. If it is loose have it repaired
by your Yamaha dealer.
1. Red cable
2. Black cable
3. Battery
1. Battery for starting
2. Battery for accessories
3. Large red lead for starting battery
4. Small red lead for accessory battery charg-
ing (optional part)
5. Large black lead
6. Negative connecting cable
7. Power for accessories
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							Maintenance
61
EMU29400Coating the boat bottom
A clean hull improves boat performance. The
boat bottom should be kept as clean of marine
growth as possible. If necessary, the boat bot-
tom can be coated with an anti-fouling paint
approved for your area to inhibit marine
growth.
Do not use anti-fouling paint which includes
copper or graphite. These paints can cause
more rapid engine corrosion.
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							Trouble Recovery
62
EMU29424
Troubleshooting
A problem in the fuel, compression, or ignition
systems can cause poor starting, loss of pow-
er, or other problems. This section describes
basic checks and possible remedies, and cov-
ers all Yamaha outboard motors. Therefore
some items may not apply to your model.
If your outboard motor requires repair, bring it
to your Yamaha dealer.
If the engine trouble warning indicator is flash-
ing, consult your Yamaha dealer.
Starter will not operate.
Q. Is battery capacity weak or low?
A. Check battery condition. Use battery of rec-
ommended capacity.
Q. Are battery connections loose or corrod-
ed?
A. Tighten battery cables and clean battery
terminals.
Q. Is fuse for electric start relay or electric cir-
cuit blown?
A. Check for cause of electric overload and
repair. Replace fuse with one of correct am-
perage.
Q. Are starter components faulty?
A. Have serviced by a Yamaha dealer.
Q. Is shift lever in gear?
A. Shift to neutral.
Engine will not start (starter operates).
Q. Is fuel tank empty?
A. Fill tank with clean, fresh fuel.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Is starting procedure incorrect?
A. See page 30.
Q. Has fuel pump malfunctioned?
A. Have serviced by a Yamaha dealer.
Q. Are spark plug(s) fouled or of incorrect
type?
A. Inspect spark plug(s). Clean or replace with
recommended type.
Q. Are spark plug cap(s) fitted incorrectly?
A. Check and re-fit cap(s).
Q. Is ignition wiring damaged or poorly con-
nected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Are ignition parts faulty?
A. Have serviced by a Yamaha dealer.
Q. Is engine stop switch lanyard not at-
tached?
A. Attach lanyard.
Q. Are engine inner parts damaged?
A. Have serviced by a Yamaha dealer.
Engine idles irregularly or stalls.
Q. Are spark plug(s) fouled or of incorrect
type?
A. Inspect spark plug(s). Clean or replace with
recommended type.
Q. Is fuel system obstructed?
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							Trouble Recovery
63
A. Check for pinched or kinked fuel line or oth-
er obstructions in fuel system.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Have ignition parts failed?
A. Have serviced by a Yamaha dealer.
Q. Has warning system activated?
A. Find and correct cause of warning.
Q. Is spark plug gap incorrect?
A. Inspect and adjust as specified.
Q. Is ignition wiring damaged or poorly con-
nected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Is specified engine oil not being used?
A. Check and replace oil as specified.
Q. Is thermostat faulty or clogged?
A. Have serviced by a Yamaha dealer.
Q. Are carburetor adjustments incorrect?
A. Have serviced by a Yamaha dealer.
Q. Is fuel pump damaged?
A. Have serviced by a Yamaha dealer.
Q. Is air vent screw on fuel tank closed?
A. Open air vent screw.
Q. Is choke knob pulled out?A. Return to home position.
Q. Is motor angle too high?
A. Return to normal operating position.
Q. Is carburetor clogged?
A. Have serviced by a Yamaha dealer.
Q. Is fuel joint connection incorrect?
A. Connect correctly.
Q. Is throttle valve adjustment incorrect?
A. Have serviced by a Yamaha dealer.
Q. Is battery cable disconnected?
A. Connect securely.
Warning buzzer sounds or indicator lights.
Q. Is cooling system clogged?
A. Check water intake for restriction.
Q. Is engine oil level low?
A. Fill oil tank with specified engine oil.
Q. Is heat range of spark plug incorrect?
A. Inspect spark plug and replace it with rec-
ommended type.
Q. Is specified engine oil not being used?
A. Check and replace oil with specified type.
Q. Is engine oil contaminated or deteriorated?
A. Replace oil with fresh, specified type.
Q. Is oil filter clogged?
A. Have serviced by a Yamaha dealer.
Q. Has oil feed/injection pump malfunc-
tioned?
A. Have serviced by a Yamaha dealer.
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