Yamaha 115 C Service Manual

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EML08210*
CHECKING PROPELLER
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You could be seriously injured if the
engine accidentally starts while you are
near the propeller.
8Before inspecting, removing or
installing the propeller, remove the
spark plug caps from the spark plugs.
Also, put the shift control in Neutral,
put the main switch in the OFF posi-
tion 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.
8Do not use your hand to hold the pro-
peller when loosening or tightening
the propeller nut. Put a wood block
between the cavitation plate and the
propeller to prevent the propeller from
turning.
1) Check each of the propeller blades for
wear, erosion from cavitation or ventila-
tion, or other damage.
2) Check the splines for wear and damage.
3) Check for fish line winding around the
propeller shaft.
Check the propeller shaft oil seal for
damage.
210012
602051
602054
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[How to remove propeller]
1) Using pliers straighten the cotter-pin and
pull it out.
2) Remove the propeller nut.
3) Remove the propeller.
1Thrust washer4Washer
2Propeller5Propeller nut
3Spacer6Cotter pin
[How to install propeller]
1) Apply Yamaha Marine grease A or
Marine grease (water-resistant grease)
to the propeller-shaft.
2) Slide the propeller over the propeller-
shaft.
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Be sure to install the thrust washer
before installing propeller, otherwise,
lower case and propeller boss may be
damaged.
3) 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.
NOTE:
When the propeller nut does not align with
the propeller shaft hole after tightening to
the specified torque, then tighten it more to
align the hole.
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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
2345 6
602041
602053
Tightening torque: 
Refer to “SPECIFICATIONS”, Page 4-1.
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EMU01460
CHANGING GEAR OIL
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8Be sure the outboard is securely fas-
tened to the transom or a stable stand.
You could be severely injured if the out-
board falls on you.
8Never get under the lower unit while it
is tilted, even when the tilt-support
lever/knob is locked. Severe injury
could occur if the outboard accidentally
falls.
1) Tilt the outboard motor so that the oil
drain plug is at the lowest point possi-
ble.
2) Place a suitable container under the
gear-case.
3) Remove the oil drain plug 1.
NOTE:
The oil drain plug is magnetic. Remove all
metal particles from the plug before rein-
stalling it.
4) Remove the oil level plug 2to allow
the oil to drain completely.
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Inspect the used oil after it has been
drained. If the oil is milky, water is get-
ting into the gear-case which can cause
gear damage. Consult a Yamaha dealer
for repair of the lower unit seals.
NOTE:
For disposal of used oil consult your
Yamaha dealer.
000565
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4-23
5) With the outboard motor in a vertical
position, and using a flexible or pres-
surized filling device, inject the gear
oil into the oil drain plug hole.
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 oil drain plug.
000377
603024
405016
Gear oil grade/capacity:
Refer to “SPECIFICATIONS,” page 4-1.
EMU14622
INSPECTING 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.
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Do not paint anodes, as this would ren-
der them ineffective.
NOTE:
Inspect ground leads attached to external
anodes on equipped models. Consult a
Yamaha dealer for inspection and
replacement of internal anodes attached
to the power unit.
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EMU04041
CHECKING BATTERY (for Electric
start models)
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Battery electrolytic fluid is dangerous; it
contains sulfuric acid and therefore is poi-
sonous and highly caustic.
Always follow these preventive mea-
sures:
8Avoid bodily contact with electrolytic
fluid as it can cause severe burns or
permanent eye injury.
8Wear protective eye gear when han-
dling or working near batteries.
Antidote (EXTERNAL):
8SKIN - Flush with water.
8EYES - Flush with water for 15 minutes
and get immediate medical attention.
Antidote (INTERNAL):
8Drink 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:
8Charge batteries in a well-ventilated
area.
8Keep batteries away from fire, sparks,
or open flames (e.g., welding equip-
ment, lighted cigarettes, etc.).
8DO NOT SMOKE when charging or han-
dling batteries.
8KEEP BATTERIES AND ELECTROLYTIC
FLUID OUT OF REACH OF CHILDREN.
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8A poorly maintained battery will quick-
ly deteriorate.
8Ordinary 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 manufactur-
er’s recommended level when neces-
sary. Top up only with distilled water
(or pure de-ionized 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 grav-
ity 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.
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UPPER  LEVELLOWER  LEVEL
000863
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EMU01304
Connecting the Battery
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Mount the battery holder securely in a
dry, well-ventilated, vibration-free loca-
tion in the boat. Install the fully charged
battery in the holder.
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8Make sure the main switch (on applica-
ble models) is “OFF” before working on
the battery.
8Reversal of the battery leads will dam-
age the rectifier.
8Connect the RED lead first when
installing the battery and disconnect
the RED lead last when removing it.
Otherwise, the electrical system can be
damaged.
8The electrical contacts of the battery
and cables must be clean and properly
connected, or the battery will not start
the engine.
Connect the RED lead to the POSITIVE (+)
terminal first. Then connect the BLACK
lead to the NEGATIVE (-) terminal.
8Using a single battery
Connect both red cables 1and 2to the
(+) terminal.
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Do not leave cable 2unconnected. If it
accidentally contacts the NEGATIVE (-)
terminal of the battery, there will be a
short circuit. Electrical system damage
and a fire could result.
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901013
901014
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EMU01280
Disconnecting the Battery
Disconnect the BLACK lead from the NEG-
ATIVE (-) terminal first. Then disconnect
the RED lead from the POSITIVE (+) termi-
nal.
1Large red lead for starting battery
2Small red lead for accessory battery charg-
ing
3Large black lead
4Battery
8Using an accessory battery
Use a connecting cable between the (-)
terminals of the starting battery and
accessory battery. See the illustrations of
the wiring connections. This cable must
be made from wire equivalent to the start-
ing battery cable 3.
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Use of smaller wire could lead to a fire.
1Battery for starting
2Battery for accessories
3Large red lead for starting battery
4Small red lead for accessory battery charg-
ing
5Large black lead
6Negative connecting cable
NOTE:
If a battery selector switch is desired, con-
sult your YAMAHA dealer about correct
wiring.
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EMU01172
CLEANING COOLING-WATER 
PASSAGES
Flushing device equipped model
Perform this procedure right after opera-
tion for the most thorough flushing.
1) After shutting off the engine, unscrew
the garden-hose connector 2from
the fitting 1on the bottom cowling.
2) Screw the garden-hose connector 2
onto a garden hose 3which is con-
nected to a fresh-water supply.
3) With the engine off, turn on the water
tap and let the water flush through
the cooling passages for about 15
minutes. Turn off the water and dis-
connect the garden hose 3.
4) When flushing is complete, reinstall
the garden-hose connector 2on the
fitting 1on the bottom cowling.
Tighten the connector securely.
EML40010
CHECKING BOLTS AND NUTS
1) Check that bolts securing the cylinder
head and engine and the nut securing
the flywheel are tightened with their
specified tightening torques.
2) Check the tightening torques of other
bolts and nuts.
000838
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EML42111
MOTOR EXTERIOR
Cleaning the Outboard Motor
After use, wash the exterior of the out-
board with fresh water. Flush the cooling
system with fresh water.
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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
cause serious overheating. Be sure the
connector is tightened securely on the fit-
ting after flushing the engine.
NOTE:
8When flushing the engine with the boat
in the water, tilting up the engine until it
is completely out of the water will
achieve better results.
8Refer to cooling system flushing
instructions in “TRANSPORTING AND
STORING OUTBOARD MOTOR”.
EMU00412
Checking Painted Surface of Motor
Check the motor for scratches, nicks, or
flaking paint. Areas with damaged paint
are more likely to corrode. If necessary,
clean and paint the areas. A touch-up
paint is available from a Yamaha dealer.
102025
EMU00413
COATING THE BOAT BOTTOM
A clean hull improves boat performance.
The boat bottom should be kept as clean
of marine growths as possible. If neces-
sary, the boat bottom 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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