Yamaha 115 C Service Manual

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4-10
EMU01202
CLEANING AND ADJUSTING SPARK
PLUG
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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
component 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 elec-
trode porcelain is very white, this could
indicate an intake air leak or carburetion
problem...

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4-11
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 esti-
mate of the correct torque is 1/4 to 1/2 a
turn past finger-tight. Have the spark plug
adjusted to the correct torque as soon as
possible with a torque-wrench.
1Spark plug gap
2Spark plug I.D. mark (NGK)
903022
q
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Spark plug torque:
Refer to...

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4-12
EMK38010
CHECKING FUEL SYSTEM
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Gasoline (petrol) and its vapors are high-
ly flammable and explosive. Keep away
from sparks, cigarettes, flames or other
sources of ignition.
Check the fuel line for leaks, cracks, or mal-
functions. If any problem is found, it should
be repaired immediately by Yamaha dealer
or other qualified mechanic.
Checking points
8Fuel system parts leakage.
8Fuel hose joint leakage.
8Fuel hose cracks or other damage.
8Fuel connector leakage.
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Leaking fuel can result in fire...

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4-13
EMK50011
CLEANING FUEL FILTER
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Gasoline (petrol) is highly flammable, and
its vapors are flammable and explosive.
8If you have any question about properly
doing this procedure, consult your
Yamaha dealer.
8Do not perform this procedure on a hot
or running engine. Allow the engine to
cool.
8There will be fuel in the fuel filter. Keep
away from sparks, cigarettes, flames or
other sources of ignition.
8This procedure will allow some fuel to
spill. Catch fuel in a rag. Wipe up any
spilled fuel...

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4-14
EMU09912
INSPECTING IDLING SPEED
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8Do not touch or remove electrical parts
when starting or during operation.
8Keep hands, hair and clothes away
from flywheel and other rotating parts
while engine is running.
cC
This procedure must be performed while
the outboard motor is in the water. A
flushing attachment or test tank can also
be used.
A diagnostic tachometer should be used
for this procedure. Results may vary
depending on whether testing is conduct-
ed with the flushing attachment, in a test...

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4-15
NOTE:
Correct idling speed inspection is only
possible if the engine is fully warmed up.
If not warmed up fully, the idle speed will
measure higher than normal. If you have
difficulty verifying the idle speed, or the
idle speed requires adjustment, consult a
Yamaha dealer or other qualified mechan-
ic.
213021
qw
EMK56010
CHECKING WATER TRAP UNDER
ENGINE OIL TANK
There is a trap at the bottom of the engine
oil tank. If water or foreign matter is visible
in this trap, consult a Yamaha dealer.
1Trap...

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4-16
EMU01329
REPLACING FUSE
If the fuse has blown on an Electric start
model, open the fuse holder and replace
the fuse with a new one of proper amper-
age.
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Be sure to use the specified fuse. An
incorrect fuse or a piece of wire may
allow excessive current flow. This could
cause electrical system damage and a fire
hazard.
NOTE:
If the new fuse blows again immediately,
consult a Yamaha dealer.
1Fuse holder
2Fuse (20A/30A)
EMK78010
CHECKING WIRING AND
CONNECTORS
1) Check that each grounding wire is...

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4-17
EMU00366
GREASING
Yamaha marine grease
(Water resistant grease)
V4
103061
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4-18
EMU00366
GREASING
Yamaha marine grease
(Water resistant grease)
V6
103062
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4-19
EML02011*
CHECKING POWER TRIM AND TILT
SYSTEM
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8Never get under the lower unit while it
is tilted, even when the tilt-support
lever is locked. Severe injury could
occur if the outboard accidentally falls.
8Make sure no one is under the out-
board 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 remote control and
engine bottom cowling (If equipped)
to check that all switches work.
3) Tilt up the...