Yamaha F250 Owners Manual

							Maintenance
65
EMU29320Checking battery (for electric start 
models)
WARNING
EWM00330
Battery electrolytic fluid is dangerous; it
contains sulfuric acid and therefore is poi-
sonous and highly caustic.
Always follow these preventive measures:

Avoid bodily contact with electrolytic
fluid as it can cause severe burns or per-
manent eye injury.

Wear protective eye gear when handling
or working near batteries.
Antidote (EXTERNAL):

SKIN - Flush with water.

EYES - Flush with water for 15 minutes
and get immediate medical attention.
Antidote (INTERNAL):

Drink 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:

Charge batteries in a well-ventilated ar-
ea.

Keep batteries away from fire, sparks, or
open flames (for example: welding
equipment, lighted cigarettes, and so
on.)

DO NOT SMOKE when charging or han-
dling batteries.
KEEP BATTERIES AND ELECTROLYTIC
FLUID OUT OF REACH OF CHILDREN.
CAUTION:
ECM00360

A poorly maintained battery will quickly
deteriorate.

Ordinary 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 manufacturer’s recom-
mended level when necessary. Top up
only with distilled water (or pure de-ion-
ized water suitable to use in batteries).
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							Maintenance
66
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 gravity 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.
EMU30730Connecting the battery
WARNING
EWM00570
Mount the battery holder securely in a dry,
well-ventilated, vibration-free location in
the boat. Install a fully charged battery in
the holder.
CAUTION:
ECM01500

Make sure the main switch (on applica-
ble models) is “” (off) before working
on the battery.

Reversal of the battery cables will dam-
age the electrical parts.

If you connect the battery cables in the
reverse order, consult a Yamaha dealer
immediately.

Connect the red battery cable first when
installing the battery and disconnect the
black battery cable first when removing
it. Otherwise, the electrical parts can will
be damaged.

The electrical contacts of the battery
and cables must be clean and properly
connected, or the battery will not start
the engine.
Connect the RED battery cable to the POSI-
TIVE (+) terminal first. Then connect the
BLACK battery cable to the NEGATIVE (-) ter-
minal.
Connecting an accessory battery (optional)
1. Remove the accessory battery coupler
cover from the outboard motor.
2. Connect the accessory battery coupler to
the coupler of the accessory battery ca-
ble (optional). Use a connecting cable be-
tween the (-) terminals of the starting
battery and accessory battery. See the il-
lustrations of the wiring connections. This
cable must be made from wire thicker
than the starting battery cable.
WARNING
EWM00600
Use of smaller wire could lead to a fire.
1. Red cable
2. Black cable
3. Battery
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							Maintenance
67
NOTE:
If connecting an accessory battery, consult
your Yamaha dealer about correct wiring.
EMU29370Disconnecting the battery
Disconnect the BLACK cable from the NEGA-
TIVE (-) terminal first. Then disconnect the
RED cable from the POSITIVE (+) terminal.
EMU31351Checking top cowling
Check the fitting of the top cowling by pushing
it with both hands. If the top cowling is loose,
reinstall the cowling. If the top cowling is still
loose after reinstalling it, have it repaired by
your Yamaha dealer.
NOTE:
Be sure to check that the gap between the top
cowling and the bottom cowling is even all
around the cowling.
EMU29400Coating the boat bottom
A clean hull improves boat performance. The
boat bottom should be kept as clean of marine
growth as possible. If necessary, the boat bot-
tom 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.
1. Battery for starting
2. Battery for accessories
3. Large red lead for starting battery
4. Small red lead for accessory battery charg-
ing (optional part)
5. Large black lead
6. Negative connecting cable
7. Power for accessories
ZMU01943
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							Trouble Recovery
68
EMU29424
Troubleshooting
A problem in the fuel, compression, or ignition
systems can cause poor starting, loss of pow-
er, or other problems. This section describes
basic checks and possible remedies, and cov-
ers all Yamaha outboard motors. Therefore
some items may not apply to your model.
If your outboard motor requires repair, bring it
to your Yamaha dealer.
If the engine trouble warning indicator is flash-
ing, consult your Yamaha dealer.
Starter will not operate.
Q. Is battery capacity weak or low?
A. Check battery condition. Use battery of rec-
ommended capacity.
Q. Are battery connections loose or corrod-
ed?
A. Tighten battery cables and clean battery
terminals.
Q. Is fuse for electric start relay or electric cir-
cuit blown?
A. Check for cause of electric overload and
repair. Replace fuse with one of correct am-
perage.
Q. Are starter components faulty?
A. Have serviced by a Yamaha dealer.
Q. Is shift lever in gear?
A. Shift to neutral.
Engine will not start (starter operates).
Q. Is fuel tank empty?
A. Fill tank with clean, fresh fuel.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Is starting procedure incorrect?
A. See page 37.
Q. Has fuel pump malfunctioned?
A. Have serviced by a Yamaha dealer.
Q. Are spark plug(s) fouled or of incorrect
type?
A. Inspect spark plug(s). Clean or replace with
recommended type.
Q. Are spark plug cap(s) fitted incorrectly?
A. Check and re-fit cap(s).
Q. Is ignition wiring damaged or poorly con-
nected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Are ignition parts faulty?
A. Have serviced by a Yamaha dealer.
Q. Is engine stop switch lanyard not at-
tached?
A. Attach lanyard.
Q. Are engine inner parts damaged?
A. Have serviced by a Yamaha dealer.
Engine idles irregularly or stalls.
Q. Are spark plug(s) fouled or of incorrect
type?
A. Inspect spark plug(s). Clean or replace with
recommended type.
Q. Is fuel system obstructed?
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							Trouble Recovery
69
A. Check for pinched or kinked fuel line or oth-
er obstructions in fuel system.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Have ignition parts failed?
A. Have serviced by a Yamaha dealer.
Q. Has warning system activated?
A. Find and correct cause of warning.
Q. Is spark plug gap incorrect?
A. Inspect and adjust as specified.
Q. Is ignition wiring damaged or poorly con-
nected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Is specified engine oil not being used?
A. Check and replace oil as specified.
Q. Is thermostat faulty or clogged?
A. Have serviced by a Yamaha dealer.
Q. Are carburetor adjustments incorrect?
A. Have serviced by a Yamaha dealer.
Q. Is fuel pump damaged?
A. Have serviced by a Yamaha dealer.
Q. Is air vent screw on fuel tank closed?
A. Open air vent screw.
Q. Is choke knob pulled out?A. Return to home position.
Q. Is motor angle too high?
A. Return to normal operating position.
Q. Is carburetor clogged?
A. Have serviced by a Yamaha dealer.
Q. Is fuel joint connection incorrect?
A. Connect correctly.
Q. Is throttle valve adjustment incorrect?
A. Have serviced by a Yamaha dealer.
Q. Is battery cable disconnected?
A. Connect securely.
Warning buzzer sounds or indicator lights.
Q. Is cooling system clogged?
A. Check water intake for restriction.
Q. Is engine oil level low?
A. Fill oil tank with specified engine oil.
Q. Is heat range of spark plug incorrect?
A. Inspect spark plug and replace it with rec-
ommended type.
Q. Is specified engine oil not being used?
A. Check and replace oil with specified type.
Q. Is engine oil contaminated or deteriorated?
A. Replace oil with fresh, specified type.
Q. Is oil filter clogged?
A. Have serviced by a Yamaha dealer.
Q. Has oil feed/injection pump malfunc-
tioned?
A. Have serviced by a Yamaha dealer.
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							Trouble Recovery
70
Q. Is load on boat improperly distributed?
A. Distribute load to place boat on an even
plane.
Q. Is water pump or thermostat faulty?
A. Have serviced by a Yamaha dealer.
Q. Is there excess water in fuel filter cup?
A. Drain filter cup.
Engine power loss.
Q. Is propeller damaged?
A. Have propeller repaired or replaced.
Q. Is propeller pitch or diameter incorrect?
A. Install correct propeller to operate outboard
at its recommended speed (r/min) range.
Q. Is trim angle incorrect?
A. Adjust trim angle to achieve most efficient
operation.
Q. Is motor mounted at incorrect height on
transom?
A. Have motor adjusted to proper transom
height.
Q. Has warning system activated?
A. Find and correct cause of warning.
Q. Is boat bottom fouled with marine growth?
A. Clean boat bottom.
Q. Are spark plug(s) fouled or of incorrect
type?
A. Inspect spark plug(s). Clean or replace with
recommended type.
Q. Are weeds or other foreign matter tangled
on gear housing?A. Remove foreign matter and clean lower
unit.
Q. Is fuel system obstructed?
A. Check for pinched or kinked fuel line or oth-
er obstructions in fuel system.
Q. Is fuel filter clogged?
A. Clean or replace filter.
Q. Is fuel contaminated or stale?
A. Fill tank with clean, fresh fuel.
Q. Is spark plug gap incorrect?
A. Inspect and adjust as specified.
Q. Is ignition wiring damaged or poorly con-
nected?
A. Check wires for wear or breaks. Tighten all
loose connections. Replace worn or broken
wires.
Q. Have electrical parts failed?
A. Have serviced by a Yamaha dealer.
Q. Is specified fuel not being used?
A. Replace fuel with specified type.
Q. Is specified engine oil not being used?
A. Check and replace oil with specified type.
Q. Is thermostat faulty or clogged?
A. Have serviced by a Yamaha dealer.
Q. Is air vent screw closed?
A. Open the air vent screw.
Q. Is fuel pump damaged?
A. Have serviced by a Yamaha dealer.
Q. Is fuel joint connection incorrect?
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							Trouble Recovery
71
A. Connect correctly.
Q. Is heat range of spark plug incorrect?
A. Inspect spark plug and replace it with rec-
ommended type.
Q. Is high pressure fuel pump drive belt bro-
ken?
A. Have serviced by a Yamaha dealer.
Q. Is engine not responding properly to shift
lever position?
A. Have serviced by a Yamaha dealer.
Engine vibrates excessively.
Q. Is propeller damaged?
A. Have propeller repaired or replaced.
Q. Is propeller shaft damaged?
A. Have serviced by a Yamaha dealer.
Q. Are weeds or other foreign matter tangled
on propeller?
A. Remove and clean propeller.
Q. Is motor mounting bolt loose?
A. Tighten bolt.
Q. Is steering pivot loose or damaged?
A. Tighten or have serviced by a Yamaha
dealer.
EMU29433
Temporary action in emergencyEMU29440Impact damage
WARNING
EWM00870
The outboard motor can be seriously dam-
aged by a collision while operating or
trailering. Damage could make the out-
board motor unsafe to operate.
If the outboard motor hits an object in the wa-
ter, follow the procedure below.
1. Stop the engine immediately.
2. Inspect the control system and all compo-
nents for damage. Also inspect the boat
for damage.
3. Whether damage is found or not, return
to the nearest harbor slowly and careful-
ly.
4. Have a Yamaha dealer inspect the out-
board motor before operating it again.
EMU29450Running single engine
When using only engine in an emergency, be
sure to keep the unused one tilted up and op-
erate the other engine at low speed.
CAUTION:
ECM00370
If the boat is operated with one engine in
the water but not running, water may run
into the exhaust pipe due to wave action,
causing engine trouble.
NOTE:
When you are maneuvering at low speed,
such as near a dock, it is recommended that
both engines be running with one in neutral
gear if possible.
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							Trouble Recovery
72
EMU29471Replacing fuse
If a fuse has blown, remove the electrical cov-
er, open the fuse holder and remove the fuse
with a fuse puller (if equipped). Replace it with
a spare one of the proper amperage.
WARNING
EWM00630
Be sure to use the specified fuse. An in-
correct fuse or a piece of wire could allow
excessive current flow. This could cause
electric system damage and a fire hazard.
NOTE:
Consult your Yamaha dealer if the new fuse
immediately blows again.
1. Electrical cover
2. Fuse puller
3. Spare fuse (5 A, 10 A, 15 A, 20 A, 30 A, 80 
A)
1. Electric throttle valve / ECM (Electronic con-
trol module) fuse (10 A)
2. Ignition coil / Fuel injector / Variable cam-
shaft timing / ECM (Electronic control mod-
ule) fuse (30 A)
3. Main switch / PTT switch fuse (20 A)
4. Starter relay fuse (30 A)
5. Fuel feed pump fuse (5 A)
6. Fuel pump fuse (15 A)
7. Engine main fuse (80 A)
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							Trouble Recovery
73
EMU29522Power trim and tilt / power tilt will not 
operate
If the engine cannot be tilted up or down with
the power trim and tilt / the power tilt because
of a discharged battery or a failure with the
power trim and tilt unit / the power tilt unit, the
engine can be tilted manually.
1. Loosen the manual valve screw by turn-
ing it counterclockwise until it stops.
2. Put the engine in the desired position,
then tighten the manual valve screw by
turning it clockwise.
EMU31591Water separator warning indicator 
blinks while cruising
WARNING
EWM01500
Gasoline is highly flammable, and its va-
pors are flammable and explosive.

Do not perform this procedure on a hot
or running engine. Allow the engine to
cool.

There will be fuel in the fuel filter. Keep
away from sparks, cigarettes, flames or
other sources of ignition.

This procedure will allow some fuel to
spill. Catch fuel in a rag. Wipe up any
spilled fuel immediately.

The fuel filter must be reassembled
carefully with the O-ring, filter cup, and
hoses in place. Improper assembly or
replacement could result in a fuel leak,
which could result in a fire or explosion
hazard.
If the water separator warning indicator on the
tachometer blinks, perform the following pro-
cedure.
1. Stop the engine.
2. Remove the top cowling.
3. Remove the holder.
8. Isolator fuse (80 A)
1. Manual valve screw
1
ZMU019051. Water separator warning indicator
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							Trouble Recovery
74
4. Disconnect the water detection switch
coupler.
CAUTION:
ECM01570
Be careful not to get any water on the wa-
ter detection switch coupler, otherwise a
malfunction could occur.
5. Unscrew the filter cup from the filter hous-
ing.
NOTE:
Be careful not to twist the water detection
switch lead when unscrewing the filter cup.
6. Drain the water in the filter cup by soaking
it up with a rag.
NOTE:
Properly dispose of the rag.
7. Firmly screw the filter cup onto the filter
housing.
NOTE:
Be careful not to twist the water detection
switch lead when screwing the filter cup onto
the filter housing.
8. Connect the water detection switch cou-
pler securely until a click is heard.
1. Holder
1. Water detection switch coupler
1. Filter cup
2. Water detection switch lead
1. Water detection switch coupler
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