Yamaha 115 C Service Manual

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3-16
cC
8Do not turn the main switch to
“START” when the engine is running.
8Do not keep the starter motor turning
for more than 5 seconds. The starter
can be damaged. The battery will also
run down quickly, making it harder to
start the engine. If the engine does
not start within 5 seconds, return the
main switch to “ON”, wait 10 sec-
onds, and then crank the engine
again.
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3-17
EMG00010
WARMING UP ENGINE
1) Before beginning operation, allow the
engine to warm up at idling speed for 3
minutes. (Failure to do this will shorten
engine life.)
2) Check for a steady flow of water from
the cooling-water pilot hole.
cC
A continuous flow of water from the pilot
hole shows that the water pump is
pumping water through the cooling pas-
sages. If water is not flowing out of the
pilot hole at all times while the engine is
running, do not continue to run the
engine. Overheating and serious dam-
age could occur. Stop the engine and
check to see if the water inlet on the
lower casing is blocked. If the problem
cannot be found and corrected, consult
your Yamaha dealer.
309013
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3-18
EMG20310
SHIFTING
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Before shifting, make sure there are no
swimmers or obstacles in the water near
you.
cC
To change the shifting position from for-
ward to reverse or vice-versa, close the
throttle first so that the engine idles (or
runs at low speeds).
FORWARD
Pull up the neutral interlock trigger (If
equipped) and move the remote control
lever quickly and firmly from Neutral to For-
ward.
REVERSE
Pull up the neutral interlock trigger (If
equipped) and move the remote control
lever quickly and firmly from Neutral to
Reverse.
w
When operating in Reverse, go slowly.
Do not open the throttle more than half.
Otherwise, the boat may become unsta-
ble, which could result in loss of control
and an accident.
701043
N
F
N
R
701044
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3-19
EMG38010
STOPPING ENGINE
Let it cool off for a few minutes at idle or
low speed first. Stopping the engine
immediately after operating at high speed
is not recommended.
EMG41511
1) Turn the main switch to “OFF”.
NOTE:
The engine can also be stopped by
pulling the lanyard from the engine stop
switch (then turning the main switch to
“OFF”).
2) Tighten the air vent screw on the fuel
tank cap after stopping the engine, if
it is equipped.
3) Remove the key if the boat will be left
unattended.
ON
START
OFF
701023
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3-20
EMU01412
TRIMMING OUTBOARD
MOTOR
The trim angle of the outboard motor
helps determine the position of the bow
of the boat in the water. The correct trim
angle will help improve performance and
fuel economy while reducing strain on the
engine. The correct trim angle depends
upon the combination of boat, engine,
and propeller. Correct trim is also affected
by variables such as the load in the boat,
sea conditions, and running speed.
w
Excessive trim for the operating condi-
tions (either trim up or trim down) can
cause boat instability and can make
steering the boat more difficult. This
increases the possibility of an accident. If
the boat begins to feel unstable or is hard
to steer, slow down and/or readjust the
trim angle.
NOTE: 
Refer to the section “ADJUSTING TRIM
ANGLE” for instructions on usage.
1Trim operating angle
q000861
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3-21ADJUSTING TRIM ANGLE
EMU01401
Power Trim/Tilt Model
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8Be sure all people are clear of the out-
board motor when adjusting the
trim/tilt angle, also be careful not to
pinch any body parts between the drive
unit and clamp bracket.
8Use caution when trying a trim position
for the first time. Increase speed gradu-
ally and watch for any signs of instabili-
ty or control problems.
8Use the power trim/tilt switch located
on the bottom engine cowling (if
equipped) only when the boat is at a
complete stop with the engine off.
The outboard motor trim angle can be
adjusted operating the power trim/tilt
switch 1.
To raise the bow (“trim-out”), push the
switch UP.
To lower the bow (“trim-in”), push the
switch DN.
Make test runs with the trim set to differ-
ent angles to find the position that works
best for your boat and operating condi-
tions.
NOTE:
To adjust the trim angle while the boat is
moving, use the power trim and tilt
switch located on the remote control
device or tiller handle, if so equipped.
UP
DN
702014*
q
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3-22
EMU19160
Trim angle settings and boat handling
When the boat is on plane, a bow-up atti-
tude results in less drag, greater stability
and efficiency. This is generally when the
keel line of the boat is up about 3 to 5
degrees. With the bow up, the boat may
have a greater tendency to steer to one
side or the other. Compensate for this as
you steer. The trim tab can also be adjust-
ed to help offset this effect.
1Optimum angle (level keel line)
2Bow up
3Bow down
Bow Up
Too much trim-out puts the bow of the
boat too high in the water. Performance
and economy are decreased because the
hull of the boat is pushing the water and
there is more air drag. Excessive trim-out
can also cause the propeller to ventilate,
which reduces performance further, and
the boat may “porpoise” (hop in the
water), which could throw the operator
and passengers overboard.
Bow Down
When the bow of the boat is down, it is
easier to accelerate from a standing start
onto plane. Too much trim-in causes the
boat to “plow” through the water,
decreasing fuel economy and making it
hard to increase speed. Operating with
excessive trim-in at higher speeds also
makes the boat unstable. Resistance at
the bow is greatly increased, heightening
the danger of “bow steering” and making
operation difficult and dangerous.
001672
q
001673
w
001674
e
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3-23
EMU01200
TILTING UP/DOWN
If the engine will be stopped for some
time, or if the boat is moored in shallows,
the engine should be tilted up to protect
the propeller and casing from damage by
collision with obstructions, and also to
reduce salt corrosion.
cC
Before tilting the motor, follow the proce-
dures under “STOPPING ENGINE”. Never
tilt the motor while the engine is running.
Severe damage from overheating can
result.
w
Be sure all people are clear of the out-
board motor when adjusting the tilt
angle, also be careful not to pinch any
body parts between the drive unit and
engine bracket.
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Leaking fuel is a fire hazard. Disconnect
the fuel line or close the fuel cock if the
engine will be tilted for more than a few
minutes. Otherwise, fuel may leak. (If the
fuel connector is provided on the motor.)
000817
NOTE:
Depending on the type of boat, the out-
board motor trim angle may have little
effect on the trim of the boat when oper-
ating.
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3-24
EMU01201
PROCEDURE FOR TILTING UP
Power trim/tilt model
1) If there is a fuel joint or a fuel cock on
the boat, disconnect the fuel line or
close the fuel cock.
2) Push the power trim/tilt switch “UP”
until the outboard has tilted up com-
pletely.
302012
UP
DOWN
UP
DN
403033
3) Turn the tilt-support lever toward you
and support the engine.
w
After tilting the engine, be sure to sup-
port it with the tilt-support lever. Other-
wise, the engine could fall back down
suddenly if oil in the power trim/tilt unit
should lose pressure.
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3-25
4) Once the engine is supported with the
tilt-support lever, push the power
trim/tilt switch DOWN to retract the
trim rods.
cC
Be sure to retract the trim rods complete-
ly during mooring. This protects the rods
from marine growths and corrosion
which could damage the power trim/tilt
mechanism.
PROCEDURE FOR TILTING DOWN
Power trim and tilt 
1) Push the power trim and tilt switch
“UP” until the engine is supported by
the tilt rod. 
2) Release the tilt-support lever. 
3) Push the power trim and tilt switch
“DN” (Down) to lower the engine to
the desired position.
EMH60010
CRUISING IN
OTHER CONDITIONS
CRUISING IN SALT WATER
After operating in salt water, wash out the
cooling-water passages with fresh water
to prevent them from becoming clogged-
up with salt deposits.
NOTE:
Refer to cooling system flushing instruc-
tions in STORING AND TRANSPORTING
OUTBOARD MOTOR.
CRUISING IN TURBID WATER
It is strongly recommended that the
optional chromium-plated water-pump kit
be installed if the outboard is to be used
in turbid (muddy) water conditions.
411014
411021
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