Yamaha F250 Owners Manual

							Operation
35
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 41.
EMU30173
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.
EMU27081Procedure for 4-stroke models
Run the engine under load (in gear with a pro-
peller installed) for 10 hours as follows.
1. First hour:
Run the engine at 2000 r/min or at ap-
proximately half throttle.
2. Second hour:
Run the engine at 3000 r/min or at ap-
proximately three-quarter throttle.
3. Remaining eight hours:
Run the engine at any speed. However,
avoid operating at full throttle for more
than 5 minutes at a time.
4. After the first 10 hours:
Operate the engine normally.
EMU27103
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.
ZMU01762
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							Operation
36
EMU31800Fuel

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.

Check the water in the fuel filter with the wa-
ter separator warning device. Place the
gear shift lever in neutral and turn the main
switch to “”(on). If the buzzer sounds and
the water separator warning indicator
blinks, consult your Yamaha dealer imme-
diately.
EMU31710Controls

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.EMU31720Stop switches

Confirm that turning the main switch to the
“” (off) position stops the engine.

Confirm that removing the lock plate from
the engine stop switch stops the engine.

Confirm that the engine cannot be started
with the lock plate removed from the engine
stop switch.
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.
EMU31341Checking 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 lev-
el mark “” and lower level mark “” . Fill
with oil if it is below the lower level mark
“”, or drain to the specified level if it is
above the upper level 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.
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
1. Oil dipstick
2. Lower level mark “”
3. Upper level mark “”
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							Operation
37
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 engineEMU31810Priming fuel system
WARNING
EWM01530

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.

Gasoline is highly flammable, and its va-
pors are flammable and explosive. Re-
frain from smoking, and keep away from
open flames and sparks.

This product emits exhaust gases which
contain carbon monoxide, a colorless,
odorless gas which could cause braindamage 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 a fuel joint or a fuel cock on the
boat, firmly connect the fuel line to the
joint or open the fuel cock.
2. Squeeze the primer pump, with the arrow
pointing up, until you feel it become firm.
EMU27490Starting engineEMU27624Electric start and remote control models
1. Place the remote control lever in “”
(neutral).
NOTE:
The start-in-gear protection device prevents
the engine from starting except when in neu-
tral.
1. Arrow
N
ZMU04588
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							Operation
38
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.
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.
ZMU04628
ON
STARTOFFON
STARTOFF
ZMU04589
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							Operation
39
EMU27670
Warming up engineEMU30031Electric 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 remains off after starting the en-
gine.
3. Check for a steady flow of water from the
cooling water pilot hole.
CAUTION:
ECM01341

If the low oil pressure warning indicator
blinks after the engine starts, stop the
engine. Otherwise serious engine dam-
age 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 cannot 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
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.
EMU31730
Shifting
WARNING
EWM00180
Before shifting, make sure there are no
swimmers or obstacles in the water near
you.
CAUTION:
ECM01610
Warm up the engine before shifting into
gear. Until the engine is warm, the idle
speed may be higher than normal. High
idle speed can prevent you from shifting
ONSTART
ZMU04596
STARTON
ZMU04590
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							Operation
40
back to neutral. If this occurs, stop the en-
gine, shift to neutral, then restart the en-
gine and allow it to warm up.
To shift out of neutral
1. Pull the neutral interlock trigger up (if
equipped).
2. Move the remote control lever firmly and
crisply forward (for forward gear) or back-
ward (for reverse gear) about 35° (a de-
tent can felt).
To shift from in gear (forward/reverse) to neu-
tral
1. Close the throttle so that the engine
slows to idle speed.
2. After the engine is at idle speed in gear
move the remote control lever firmly and
crisply into the neutral position.
EMU31741
Braking
WARNING
EWM01510

Do not use the reverse function to slow
down or stop the boat as it could cause
you to lose control, be ejected, or impact
the steering wheel or other parts of the
boat. This could increase the risk of se-
rious injury. It could also damage the
shift mechanism.

Do not shift into reverse while traveling
at planing speeds. Loss of control, boat
swamping, or damage to the boat could
occur.
The boat is not equipped with a separate
braking system. It is stopped by water resis-
tance after the throttle lever is moved back to
idle. The stopping distance varies depending
on gross weight, water surface conditions,
and wind direction.
EMU27820
Stopping engine
Before stopping the engine, first let it cool off
for a few minutes at idle or low speed. Stop-
ping the engine immediately after operating at
high speed is not recommended.
EMU31830Procedure
1. Turn the main switch to “” (off).
N
ZMU04588
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							Operation
41
2. Remove the key if the boat will be left un-
attended.
NOTE:
The engine can also be stopped by pulling the
lanyard and removing the clip from the engine
stop switch, then turning the main switch to
“” (off).
EMU27861
Trimming outboard motor
The trim angle of the outboard motor helps
determine the position of the bow of the boat
in the water. Correct trim angle will help im-
prove performance and fuel economy while
reducing strain on the engine. Correct trim an-
gle depends upon the combination of boat,
engine, and propeller. Correct trim is also af-
fected by variables such as the load in the
boat, sea conditions, and running speed.
WARNING
EWM00740
Excessive trim for the operating condi-
tions (either trim up or trim down) can
cause boat instability and can make steer-
ing 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.
EMU27882Adjusting trim angle
Power trim and tilt models
WARNING
EWM00751

Be sure all people are clear of the out-
board motor when adjusting the tilt an-
gle, also be careful not to pinch any
body parts between the drive unit and
clamp bracket.

Use caution when trying a trim position
for the first time. Increase speed gradu-
ally and watch for any signs of instability
or control problems. Improper trim an-
gle can cause loss of control.

If equipped with a power trim and tilt
switch located on the bottom cowling,
use the switch only when the boat is at a
complete stop with the engine off. Do
not adjust the trim angle with this switch
while the boat is moving.
ON OFF START
ZMU04599
OFFONOFFON
ZMU046001. Trim operating angle
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							Operation
42
Adjust the outboard motor trim angle using
the power trim and tilt switch.
To raise the bow (trim-out), press the switch
“” (up).
To lower the bow (trim-in), press the switch
“” (down).Make test runs with the trim set to different an-
gles to find the position that works best for
your boat and operating conditions.
EMU27911Adjusting boat trim
When the boat is on plane, a bow-up attitude
results in less drag, greater stability and effi-
ciency. 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 tenden-
cy to steer to one side or the other. Compen-
sate for this as you steer. The trim tab can
also be adjusted to help offset this effect.
When the bow of the boat is down, it is easier
to accelerate from a standing start onto plane.
Bow Up
Too much trim-out puts the bow of the boat
too high in the water. Performance and econ-
omy 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 perfor-
mance further, and the boat may “porpoise”
(hop in the water), which could throw the op-
erator and passengers overboard.
1. Power trim and tilt switch
1. Power trim and tilt switch
1. Power trim and tilt switch
UP
DN
1
ZMU04193
ZMU04601
DN
UP1
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							Operation
43
Bow Down
Too much trim-in causes the boat to “plow”
through the water, decreasing fuel economy
and making it hard to increase speed. Operat-
ing 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 opera-
tion difficult and dangerous.
NOTE:
Depending on the type of boat, the outboard
motor trim angle may have little effect on the
trim of the boat when operating.
EMU27942
Tilting up and down
If the engine will be stopped for some time or
if the boat is moored in shallows, the outboard
motor should be tilted up to protect the propel-
ler and lower case from damage by collision
with obstructions, and also to reduce salt cor-
rosion.
WARNING
EWM01540
Be sure all people are clear of the out-
board motor when tilting up and down,
also be careful not to pinch any body parts
between the drive unit and engine bracket.
CAUTION:
ECM00991

Before tilting the outboard motor, follow
the procedure under “Stopping engine”
in this chapter. Never tilt the outboard
motor while the engine is running. Se-
vere damage from overheating can re-
sult.

To prevent the cooling water passages
from becoming frozen when the ambient
temperature is 5°C or below, tilt the out-
board motor up after it has been
stopped 30 seconds or more.
EMU28007Procedure for tilting up (power trim 
and tilt models / power tilt models)
1. Place the remote control lever / gear shift
lever in neutral.
2. Disconnect the fuel line from the out-
board motor or close the fuel cock.
3. Press the power trim and tilt switch / pow-
er tilt switch “” (up) until the outboard
motor has tilted up completely.
N
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							Operation
44
4. Push the tilt support knob into the clamp
bracket or pull the tilt support lever toward
you to support the engine.
WARNING
EWM00260
After tilting the outboard motor, be sure to
support it with the tilt support knob or tilt
support lever. Otherwise the outboard mo-
tor could fall back down suddenly if oil in
the power trim and tilt unit loses pressure.
5. Models equipped with trim rods: Once the
outboard motor is supported with the tilt
support lever, press the power trim and
tilt switch / power tilt switch “” (down) to
retract the trim rods.
CAUTION:
ECM00250
Be sure to retract the trim rods completely
during mooring. This protects the rods
from marine growth and corrosion which
could damage the power trim and tilt
mechanism.
UP
ZMU04194
ZMU04602
UP
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