Yamaha F150 Four Stroke Manual

							Maintenance
44
ging hole of the silencer cover, if
equipped. When properly done, the en-
gine will smoke excessively and almost
stall.
8. Remove the flushing attachment and
wipe off any excess water.
9. Install the top cowling and propeller.
10. Drain the cooling water completely out of
the motor. Clean the body thoroughly.
NOTE:
A flushing attachment is available from your
Yamaha dealer.
EMU28400Lubrication (except oil injection 
models)
1. Grease the spark plug threads and install
the spark plug(s) and torque to proper
specification. For information on spark
plug installation, see page 49.
2. Change the gear oil. For instructions, see
page 57. Inspect the oil for the presence
of water that indicates a leaky seal. Seal
replacement should be performed by an
authorized Yamaha dealer prior to use.
3. Grease all grease fittings. For further de-
tails, see page 49.
EMU28421Cleaning and anticorrosion measures
1. Wash down the exterior of the outboard
motor with fresh water and dry off com-
pletely.
2. Spray the outboard motor exterior with
“Yamaha Silicone Protectant” (Part No.
LUB-SILCNE-13-00).
3. Wax the cowling with a non-abrasive wax
such as “Yamaha Silicone Wax” (Part No.
ACC-11000-15-02).
EMU28430Battery care
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):

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.
Batteries vary among manufacturers. There-
fore the following procedures may not always
apply. Consult your battery manufacturer’s in-
structions.
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							Maintenance
45
Procedure
1. Disconnect and remove the battery from
the boat. Always disconnect the black
negative cable first to prevent the risk of
shorting.
2. Clean the battery casing and terminals.
Fill each cell to the upper level with dis-
tilled water.
3. Store the battery on a level surface in a
cool, dry, well-ventilated place out of di-
rect sunlight.
4. Once a month, check the specific gravity
of the electrolyte and recharge as re-
quired to prolong battery life.
EMU28441Flushing power unit
Perform this procedure right after operation
for the most thorough flushing.
CAUTION:
ECM01530
Do not perform this procedure while the
engine is running. The water pump may be
damaged and severe damage from over-
heating can result.
1. After shutting off the engine, unscrew the
garden hose connector from the fitting on
the bottom cowling.2. Screw the garden hose connector onto a
garden hose which is connected to a
fresh water supply.
3. With the engine off, turn on the water tap
and let the water flush through the cool-
ing passages for about 15 minutes. Turn
off the water and disconnect the garden
hose.
4. When flushing is complete, reinstall the
garden hose connector on the fitting on
the bottom cowling. Tighten the connec-
tor securely.
CAUTION:
ECM00540
Do not leave the garden hose connector
loose on the bottom cowling fitting or let
the hose hang free during normal opera-
tion. Water will leak out of the connector
instead of cooling the engine, which can
1. Fitting
2. Garden hose connector
3. Garden hose
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							Maintenance
46
cause serious overheating. Be sure the
connector is tightened securely on the fit-
ting after flushing the engine.
NOTE:

When flushing the engine with the boat in
the water, tilting up the outboard motor until
it is completely out of the water will achieve
better results.

For cooling system flushing instructions,
see page 42.
EMU28450Cleaning the outboard motor
After use, wash the exterior of the outboard
motor with fresh water. Flush the cooling sys-
tem with fresh water.
NOTE:
For cooling system flushing instructions, see
page 42.
EMU28460Checking painted surface of motor
Check the motor for scratches, nicks, or flak-
ing paint. Areas with damaged paint are more
likely to corrode. If necessary, clean and paint
the areas. A touch-up paint is available from
your Yamaha dealer.
EMU28486
Periodic maintenance
WARNING
EWM01070
Be sure to turn off the engine when you
perform maintenance unless otherwise
specified. If you or the owner is not famil-
iar with machine servicing, this work
should be done by your Yamaha dealer or
other qualified mechanic.
Maintenance, replacement, or repair of the
emission control devices and systems
may be performed by any marine engine
repair establishment or individual. All war-
ranty repairs, however, including those to
the emission control system, must be per-
formed by an authorized Yamaha marine
dealership.
A service manual is available for purchase
through your Yamaha dealer for owners who
have the mechanical skills, tools, and other
equipment necessary to perform mainte-
nance not covered by this owner’s manual.
EMU28510Replacement parts
If replacement parts are necessary, use only
genuine Yamaha parts or parts of the same
type and of equivalent strength and materials.
Any part of inferior quality may malfunction,
and the resulting loss of control could endan-
ger the operator and passengers. Yamaha
genuine parts and accessories are available
from your Yamaha dealer.
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							Maintenance
47
EMU30562Maintenance chart
NOTE:

Refer to the sections in this chapter for explanations of each owner-specific action.

The maintenance cycle on these charts assume usage of 200 hours per year and regular
flushing of the cooling water passages. Maintenance frequency should be adjusted accord-
ing to usage conditions.

Disassembly or repairs may be necessary depending on the outcome of maintenance
checks.

Expendable or consumable parts and lubricants will lose their effectiveness over time and
through normal usage regardless of the warranty period.

When operating in salt water, turbid or muddy water, the engine should be flushed with clean
water after each use.
The “” symbol indicates the check-ups which you may carry out yourself.
The “” symbol indicates work to be carried out by your Yamaha dealer.
Item ActionsInitial Every
10 hours 
(1 month)50 hours 
(3 months)100 hours 
(6 months)200 hours 
(1 year)
Anode(s) (external)Inspection / replace-
ment
Anode(s) (cylinder 
head,  thermostat cov-
er)Inspection / replace-
ment
Battery Inspection / charging
Cooling water passag-
esCleaning
Cowling clamp Inspection
Fuel filter (can be dis-
assembled)Inspection / cleaning
Fuel system Inspection
Gear oil Change
Greasing points Greasing
Idling speed (EFI mod-
els)Inspection
PCV (Pressure Con-
trol Valve)Inspection
Power trim and tilt unit Inspection
Propeller and cotter pinInspection / replace-
ment
Shift link / shift cable Inspection / adjustment
ThermostatInspection / replace-
ment
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							Maintenance
48
EMU28874Maintenance chart (additional)
EMU28910
NOTE:
When using lead or high-sulfur gasoline, inspecting valve clearance may be required more fre-
quently than every 500 hours.
Throttle link / throttle 
cable / throttle pick-up 
timingInspection / adjustment
Water pumpInspection / replace-
ment
Engine oil Inspection / change
Oil filter (cartridge) Change
Spark plug(s)Cleaning / adjustment / 
replacement
Timing beltInspection / replace-
ment
Item ActionsEvery
500 hours (2.5 years) 1000 hours (5 years)
Timing belt Replacement
Valve clearance 
(DOHC)Inspection / adjustment
Fuel filter (vapor sepa-
rator tank)Replacement
Anode(s) (exhaust cov-
er, cover joint)Replacement
Exhaust guide, exhaust 
manifoldInspection / replace-
ment Item ActionsInitial Every
10 hours 
(1 month)50 hours 
(3 months)100 hours 
(6 months)200 hours 
(1 year)
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							Maintenance
49
EMU28931Greasing
Yamaha marine grease (Water resistant grease)
EMU28952Cleaning and adjusting spark plug
WARNING
EWM00560
When removing or installing a spark plug,
be careful not to damage the insulator. A
damaged insulator could allow external
sparks, which could lead to explosion or
fire.
The spark plug is an important engine compo-
nent and is easy to inspect. The condition of
the spark plug can indicate something about
the condition of the engine. For example, if the
center electrode porcelain is very white, this
could indicate an intake air leak or carburetion
problem in that cylinder. Do not attempt to di-
agnose any problems yourself. Instead, take
the outboard motor to a Yamaha dealer. You
should periodically remove and inspect the
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							Maintenance
50
spark plug because heat and deposits will
cause the spark plug to slowly break down
and erode. If electrode erosion becomes ex-
cessive, or if carbon and other deposits are
excessive, you should replace the spark plug
with another of the correct type.
Before fitting the spark plug, measure the
electrode gap with a wire thickness gauge;
adjust the gap to specification if necessary.
When fitting the plug, always clean the gasket
surface and use a new gasket. Wipe off any
dirt from the threads and screw in the spark
plug to the correct torque.
NOTE:
If a torque-wrench is not available when you
are fitting a spark plug, a good estimate of the
correct torque is 1/4 to 1/2 a turn past finger-tight. Have the spark plug adjusted to the cor-
rect torque as soon as possible with a torque-
wrench.
EMU28962Checking fuel system
WARNING
EWM00060
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other sourc-
es of ignition.
WARNING
EWM00910
Leaking fuel can result in fire or explosion.

Check for fuel leakage regularly.

If any fuel leakage is found, the fuel sys-
tem must be repaired by a qualified me-
chanic. Improper repairs can make the
outboard unsafe to operate.
Check the fuel lines for leaks, crack, or mal-
function. If a problem is found, your Yamaha
dealer or other qualified mechanic should re-
pair it immediately. Standard spark plug:
LFR5A-11
1. Spark plug gap
2. Spark plug I.D. mark (NGK)
Spark plug gap:
1.0–1.1 mm (0.039–0.043 in)
Spark plug torque:
25.0 Nm (18.4 ft-lb) (2.55 kgf-m)
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							Maintenance
51
Checkpoints

Fuel system parts leakage

Fuel line joint leakage

Fuel line cracks or other damage

Fuel connector leakageEMU28980Inspecting fuel filter
WARNING
EWM00310
Gasoline is highly flammable, and its va-
pors are flammable and explosive.

If you have any question about properly
doing this procedure, consult your
Yamaha dealer.

Do not perform this procedure on a hot
or running engine. Allow the engine to
cool.

There will be fuel in the fuel filter. Keep
away from sparks, cigarettes, flames or
other sources of ignition.

This procedure will allow some fuel to
spill. Catch fuel in a rag. Wipe up any
spilled fuel immediately.

The fuel filter must be reassembled
carefully with the O-ring, filter cup, and
hoses in place. Improper assembly or
replacement could result in a fuel leak,
which could result in a fire or explosion
hazard.
EMU29961Cleaning fuel filter
1. Loosen the filter cup ring nut.
2. Remove the filter cup, catching any
spilled fuel in a rag.
3. Remove the filter element, and wash it in
solvent. Allow it to dry. Inspect the filter el-
ement and O-ring to make sure they are
in good condition. Replace them if neces-
sary. If any water is found in the fuel, the
Yamaha portable fuel tank or other fuel
tanks should be checked and cleaned.
1. Locking tab
2. Filter cup ring nut
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							Maintenance
52
4. Install the filter element and filter cup into
the filter housing.
5. Tighten the ring nut so that one of the
larger ring nut tabs is aligned with the lock
tab.
6. Run the engine and check the filter and
lines for leaks.
NOTE:
If any water is in the fuel, the red ring in the
fuel filter unit will float. If so, remove the cup
and drain the water.
EMU29073Changing engine oil
WARNING
EWM00760

Avoid draining the engine oil immediate-
ly after stopping the engine. The oil is
hot and should be handled with care to
avoid burns.

Be sure the outboard motor is securely
fastened to the transom or a stable
stand.
CAUTION:
ECM00970

Do not overfill the oil, and be sure the
outboard motor is upright (not tilted)
when checking and changing the engine
oil.

If the oil level is above the upper level
mark, drain until the level meets the
specified capacity. Overfilling the oil
could cause leakage or damage.
CAUTION:
ECM01240
Change the engine oil after the first 10
hours of operation, and every 100 hours or
at 6-month intervals thereafter. Otherwise
the engine will wear quickly.
NOTE:
Change the engine oil when the oil is still
warm.
1. Put the outboard motor in an upright po-
sition (not tilted).
1. Filter cup
2. Filter cup ring nut
3. Filter housing
4. O-ring
5. Filter element
6. Float
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							Maintenance
53
2. Prepare a suitable container that holds a
larger amount than the engine oil capaci-
ty. Loosen and remove the drain screw
while holding the container under the
drain hole. Then remove the oil filler cap.
Let the oil drain completely. Wipe up any
spilled oil immediately.
3. Put a new gasket on the oil drain screw.
Apply a light coat of oil to the gasket and
install the drain screw.
NOTE:
If a torque wrench is not available when you
are installing the drain screw, finger tighten
the screw just until the gasket comes into con-
tact with the surface of the drain hole. Thentighten 1/4 to 1/2 turn more. Tighten the drain
screw to the correct torque with a torque
wrench as soon as possible.
4. Add the correct amount of oil through the
filler hole. Install the filler cap.
5. Start the engine and watch to make sure
the low oil pressure warning indicator (if
equipped) turns off. Make sure that there
are no oil leaks.
CAUTION:
ECM00680
If the low oil pressure warning indicator
does not turn off or if there are oil leaks,
stop the engine and find the cause. Con-
tinued operation with a problem could
cause severe engine damage. Consult
your Yamaha dealer if the problem cannot
be located and corrected.
6. Turn off the engine and wait 3 minutes.
Recheck the oil level using the dipstick to
be sure the level falls between the upper
and lower marks. Fill with oil if it is below
the lower mark, or drain to the specified
level if it is above the upper mark.
1. Drain screw
Drain screw tightening torque:
28.0 Nm (20.7 ft-lb) (2.86 kgf-m)
Recommended engine oil:
4-stroke outboard motor oil
Engine oil quantity (excluding oil filter):
5.2 L (5.50 US qt) (4.58 Imp.qt)
1. Oil filler cap
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