Yamaha F150 Four Stroke Manual

							Basic components
24
NOTE:
If twin engines are installed on your boat, the
gauge will only display the total fuel economy
of both engines.
NOTE:

Fuel consumption varies greatly with boat
design, weight, propeller used, engine trim
angle, sea conditions (including wind), and
throttle position. Fuel consumption also var-
ies slightly with the type of water (salt, fresh,
and contaminate levels), air temperature
and humidity, cleanliness of the boat bot-
tom, engine mounting height, skill of the op-
erator, and individual gasoline formulation
(winter or summer fuel and amount of addi-
tives).

The Yamaha digital speedometer and fuel
management meter calculates speed,
miles traveled, and fuel economy by water
movement at the stern of the boat. This dis-
tance can vary greatly from the actual dis-
tance traveled because of water currents,
sea swells, and the condition of the water
speed sensor (partially plugged or dam-
aged).

Individual engines may slightly vary in their
fuel consumption due to manufacturing
variations. These variations can be even
greater if the engines are of different year
models. In addition, variations in propellers,even of the same basic dimensions of the
same design, can also cause a slight varia-
tion in fuel consumption.
EMU26780Twin-engine speed synchronizer
This gauge displays the difference in engine
speed (r/min) between the port and starboard
engines for reference purposes when syn-
chronizing the two engines’ speeds.
Press the “” (mode) button repeatedly
until the indicator on the face of the gauge
points to “” (synchronizer).
ZMU01752
1. Port engine speed is higher
2. Port engine speed is slightly higher
3. Engine speed is synchronized evenly be-
tween port and starboard engines
4. Starboard engine speed is slightly higher
5. Starboard engine speed is higher
ZMU01753
ZMU01754
1
2
3
4
5
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							Basic components
25
NOTE:
If the two engines’ speeds are not synchro-
nized while cruising, they can be synchro-
nized by adjusting trim angle or throttle.
EMU26791Water separator warning indicator
This indicator will blink when water has accu-
mulated in the water separator. In such an
event, stop the engine and drain the water
from the separator.
NOTE:
This indicator only operates when a water
separator sensor is equipped.
EMU26801
Warning system
CAUTION:
ECM00090
Do not continue to operate the engine if a
warning device has activated. Consult
your Yamaha dealer if the problem cannot
be located and corrected.
EMU26823Overheat warning (twin engines)
This engine has an overheat warning device.
If the engine temperature rises too high, the
warning device will activate.
Activation of warning device

The engine speed will automatically de-
crease to about 2000 r/min.

If equipped with an overheat warning indi-
cator, it will light.

The buzzer will sound.
If the warning system has activated, stop the
engine and check the cooling water inlet for
clogging.
NOTE:
Dual engine drive users:
ZMU01755
ZMU01757
OFF STARTONOFF STARTON
ZMU04584
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							Basic components
26
Should the overheat warning system of one
engine activate, the engine will slow down
and the buzzer will sound. This will cause the
other engine to slow down and the buzzer to
sound. To switch off the warning activation on
the engine not affected by overheating, turn
off the main switch of the engine overheating.
EMU26854Low oil pressure warning
If the oil pressure drops too low, the warning
device will activate.
Activation of warning device

The engine speed will automatically de-
crease to about 2000 r/min.

The low oil pressure warning indicator will
light.

The buzzer will sound.If the warning system has activated, stop the
engine as soon as it is safe to do so. Check
the oil level and add oil as needed. If the oil
level is correct and the warning device does
not switch off, consult your Yamaha dealer.
CAUTION:
ECM00100
Do not continue to run the engine if the
low oil pressure warning indicator is on.
Serious engine damage could occur.
ZMU01828
OFF STARTONOFF STARTON
ZMU04584
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							Operation
27
EMU26901
Installation
CAUTION:
ECM00110
Incorrect engine height or obstructions to
smooth water flow (such as the design or
condition of the boat, or accessories such
as transom ladders or depth finder trans-
ducers) can create airborne water spray
while the boat is cruising. Severe engine
damage may result if the motor is operat-
ed continuously in the presence of air-
borne water spray.
NOTE:
During water testing check the buoyancy of
the boat, at rest, with its maximum load.
Check that the static water level on the ex-
haust housing is low enough to prevent water
entry into the powerhead, when water rises
due to waves when the outboard is not run-
ning.
EMU26910Mounting the outboard motor
WARNING
EWM00820

Overpowering a boat could cause se-
vere instability. Do not install an out-
board motor with more horsepower than
the maximum rating on the capacity
plate of the boat. If the boat does not
have a capacity plate, consult the boat
manufacturer.

The information presented in this sec-
tion is intended as reference only. It is
not possible to provide complete in-
structions for every possible boat and
motor combination. Proper mounting
depends in part on experience and the
specific boat and motor combination.
WARNING
EWM00830
Improper mounting of the outboard motor
could result in hazardous conditions such
as poor handling, loss of control, or fire
hazards. Observe the following:

For permanently mounted models, your
dealer or other person experienced in
proper rigging should mount the motor.
If you are mounting the motor yourself,
you should be trained by an experienced
person.

For portable models, your dealer or oth-
er person experienced in proper out-
board motor mounting should show you
how to mount your motor.
Mount the outboard motor on the center line
(keel line) of the boat, and ensure that the
boat itself is well balanced. Otherwise the
boat will be hard to steer. For boats without a
keel or which are asymmetrical, consult your
dealer.
1. Center line (keel line)
ZMU017601
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							Operation
28
EMU26930Mounting height (boat bottom)
To run your boat at optimum efficiency, the
water resistance (drag) of the boat and out-
board motor must be made as little as possi-
ble. The mounting height of the outboard
motor greatly affects the water resistance. If
the mounting height is too high, cavitation
tends to occur, thus reducing the propulsion;
and if the propeller tips cut the air, the engine
speed will rise abnormally and cause the en-
gine to overheat. If the mounting height is too
low, the water resistance will increase and
thereby reduce engine efficiency. Mount the
outboard motor so that the anti-cavitation
plate is in alignment with the bottom of the
boat.
NOTE:

The optimum mounting height of the out-
board motor is affected by the boat/motor
combination and the desired use. Test runs
at different heights can help determine the
optimum mounting height. Consult your
Yamaha dealer or boat manufacturer for
further information on determining the prop-
er mounting height.

For instructions on setting the trim angle of
the outboard motor, see page 34.
EMU30172
Breaking in engine
Your new engine requires a period of break-in
to allow mating surfaces of moving parts to
wear in evenly. Correct break-in will help en-
sure proper performance and longer engine
life.
CAUTION:
ECM00800
Failure to follow the break-in procedure
could result in reduced engine life or even
severe engine damage.
EMU27080Procedure for 4-stroke models
Run the engine under load (in gear with a pro-
peller installed) as follows.
1. For the first hour of operation:
Run the engine at 2000 r/min or at ap-
proximately half throttle.
2. For the second hour of operation:
Run the engine at 3000 r/min or at ap-
proximately three-quarter throttle.
3. For the next eight hours of operation:
Avoid continuous operation at full throttle
for more than five minutes at a time.
4. After the first 10 hours:
Operate the engine normally.
1. Center line (keel line)
ZMU01762
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							Operation
29
EMU27102
Preoperation checks
WARNING
EWM00080
If any item in the preoperation check is not
working properly, have it inspected and
repaired before operating the outboard
motor. Otherwise an accident could occur.
CAUTION:
ECM00120
Do not start the engine out of water. Over-
heating and serious engine damage can
occur.
EMU27111Fuel

Check to be sure you have plenty of fuel for
your trip.

Make sure there are no fuel leaks or gaso-
line fumes.

Check fuel line connections to be sure they
are tight (if equipped Yamaha fuel tank or
boat tank).

Be sure the fuel tank is positioned on a se-
cure, flat surface, and that the fuel line is not
twisted or flattened, or likely to contact
sharp objects (if equipped Yamaha fuel
tank or boat tank).
EMU27130Controls

Check throttle, shift, and steering for proper
operation before starting the engine.

The controls should work smoothly, without
binding or unusual free play.

Look for loose or damaged connections.

Check operation of the starter and stop
switches when the outboard motor is in the
water.
EMU27150Engine

Check the engine and engine mounting.

Look for loose or damaged fasteners.

Check the propeller for damage.

Check that the battery is in good condition
and the battery connections are secure.
EMU27163Checking the engine oil level
1. Put the outboard motor in an upright po-
sition (not tilted).
2. Remove oil dipstick and wipe it clean.
3. Completely insert the dipstick and re-
move it again.
4. Check 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.
NOTE:
Be sure to completely insert the dipstick into
the dipstick guide.
EMU30021
Filling fuel
WARNING
EWM00060
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other sourc-
es of ignition.
1. Remove the fuel tank cap.
2. Carefully fill the fuel tank.
1. Oil dipstick
2. Lower level mark
3. Upper level mark
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							Operation
30
3. Securely close the cap after filling the
tank. Wipe up any spilled fuel.
EMU27270Ring Free Fuel Additive
Gasoline is a precise blend of many different
substances, each chosen to give certain char-
acteristics. Gasoline blends have been
changing in recent years in response to con-
cerns about pollution and resulting emissions
regulations. One of the most obvious changes
has been the elimination of lead from most fu-
els.
As gasoline has changed, the amount of addi-
tives such as aromatics and oxygenates has
increased. These additives are important for
the engines in passenger cars, but they can
have detrimental effects in marine engines,
because of increased deposits in the combus-
tion chamber. When enough deposits collect,
piston rings begin sticking. Performance
drops and engine wear increases dramatical-
ly.
While many additives available may reduce
deposits, Yamaha recommends the use of
Ring Free Fuel Additive, available from your
Yamaha dealer. Ring Free Fuel Additive
has repeatedly proven its ability to clean com-
bustion deposits from inside the engine, nota-
bly the critical piston-ring-land area, and fuel
system components. Follow product labeling
for use instructions.
EMU27450
Operating engineEMU27480Feeding fuel
WARNING
EWM00420

Before starting the engine, make sure
that the boat is tightly moored and that
you can steer clear of any obstructions.
Be sure there are no swimmers in the
water near you.

When the air vent screw is loosened,
gasoline vapor will be released. Gaso-
line is highly flammable, and its vapors
are flammable and explosive. Refrain
from smoking, and keep away from
open flames and sparks while loosening
the air vent screw.

This product emits exhaust gases which
contain carbon monoxide, a colorless,
odorless gas which could cause brain
damage or death when inhaled. Symp-
toms include nausea, dizziness, and
drowsiness. Keep cockpit and cabin ar-
eas well ventilated. Avoid blocking ex-
haust outlets.
1. If there is an air vent screw on the fuel
tank cap, loosen it 2 or 3 turns.
2. If there is a fuel joint or a fuel cock on the
boat, firmly connect the fuel line to the
joint or open the fuel cock.
3. Squeeze the primer pump with the outlet
end up until you feel it become firm.
EMU27490Starting engineEMU27624Electric start and remote control models
1. Place the remote control lever in “”
(neutral).
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							Operation
31
NOTE:
The start-in-gear protection device prevents
the engine from starting except when in neu-
tral.
2. Attach the engine stop switch lanyard to
a secure place on your clothing, or your
arm or leg. Then install the lock plate on
the other end of the lanyard into the en-
gine stop switch.
WARNING
EWM00120

Attach the engine stop switch lanyard to
a secure place on your clothing, or your
arm or leg while operating.

Do not attach the lanyard to clothing
that could tear loose. Do not route the
lanyard where it could become entan-
gled, preventing it from functioning.

Avoid accidentally pulling the lanyard
during normal operation. Loss of engine
power means the loss of most steering
control. Also, without engine power, the
boat could slow rapidly. This could
cause people and objects in the boat to
be thrown forward.
3. Turn the main switch to “” (on).
NOTE:
Dual engine users: When the main switch is
turned on, the buzzer operates for a few sec-
onds then stops automatically. The buzzer
also operates if one of the engines stalls.
N
ZMU04588
ON
STARTOFFON
STARTOFF
ZMU04589
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							Operation
32
4. Turn the main switch to “” (start),
and hold it for a maximum of 5 seconds.
5. Immediately after the engine starts, re-
lease the main switch to return it to “”
(on).
CAUTION:
ECM00191

Never turn the main switch to “”
(start) while the engine is running.

Do not keep the starter motor turning for
more than 5 seconds. If the starter motor
is turned continuously for more than 5
seconds, the battery will be quickly dis-
charged, thus making it impossible to
start the engine. The starter can also be
damaged. If the engine will not start after
5 seconds of cranking, return the main
switch to “” (on), wait 10 seconds,
then crank the engine again.
EMU27670
Warming up engineEMU30030Manual start and electric start models
1. After starting the engine, allow it to idle for
3 minutes to warm up. Failure to do so will
shorten engine life.
2. Be sure the low oil pressure warning indi-
cator goes off after starting the engine.
3. Check for a steady flow of water from the
cooling water pilot hole.
CAUTION:
ECM01340

If the low oil pressure warning indicator
does not go off after the engine starts,
stop the engine. Otherwise serious en-
gine damage could occur. Check the oil
level and add oil if necessary. Consult
your Yamaha dealer if the cause for the
low oil pressure warning indicator can-
not be found.

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, overheating and serious dam-
age could occur. Stop the engine and
check whether the cooling water inlet on
the lower case or the cooling water pilot
ONSTARTOFF
ZMU01881
STARTON
ZMU04590
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							Operation
33
hole is blocked. Consult your Yamaha
dealer if the problem cannot be located
and corrected.

If the cooling passage is frozen, it may
take awhile for water to start flowing out
of the pilot hole.
EMU27740
Shifting
WARNING
EWM00180
Before shifting, make sure there are no
swimmers or obstacles in the water near
you.
CAUTION:
ECM00220
To change the boat direction or shifting
position from forward to reverse or vice-
versa, first close the throttle so that the en-
gine idles (or runs at low speeds).
EMU27763Forward (tiller handle and remote 
control models)
Tiller control models
1. Place the throttle grip in the fully closed
position.
2. Move the gear shift lever quickly and firm-
ly from neutral to forward.Remote control models
Pull up the neutral interlock trigger (if
equipped) and move the remote control lever
quickly and firmly from neutral to forward.
EMU27784Reverse (automatic reverse lock and 
power trim and tilt models)
WARNING
EWM00190
When operating in reverse, go slowly. Do
not open the throttle more than half. Other-
wise the boat could become unstable,
which could result in loss of control and
an accident.
Tiller control models
1. Place the throttle grip in the fully closed
position.
2. Move the gear shift lever quickly and firm-
ly from neutral to reverse.
N
F
ZMU04597
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