Yamaha F150 Four Stroke Manual

							Trouble Recovery
64
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
65
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.
EMU29432
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
66
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.
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.
1. Electrical cover
2. Fuse puller
3. Accessory fuse (50 A)
4. Main fuse (50 A)
5. Main switch / trim switch fuse (20 A)
6. Engine control unit / ignition coil / electric 
fuel pump / fuel injector / ISC (idle speed 
control) fuse (20 A)
7. Starter relay fuse (30 A)
8. Spare fuse (20 A, 30 A, 50 A)
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							Trouble Recovery
67
2. Put the engine in the desired position,
then tighten the manual valve screw by
turning it clockwise.
EMU29760
Treatment of submerged motor
If the outboard motor is submerged, immedi-
ately take it to a Yamaha dealer. Otherwise
some corrosion may begin almost immediate-
ly.
If you cannot immediately take the outboard
motor to a Yamaha dealer, follow the proce-
dure below in order to minimize engine dam-
age.
EMU29970Procedure
1. Thoroughly wash away mud, salt, sea-
weed, and so on, with fresh water.
2. Remove the spark plugs and face the
spark plug holes downward to allow any
water, mud, or contaminants to drain.
3. Drain the fuel from the vapor separator,
fuel filter, and fuel line.
4. Spray “Fogging Oil” or supply engine oil
through the intake manifold and spark
plug holes while rotating the flywheel
manually.
5. Take the outboard motor to a Yamaha
dealer as soon as possible.
CAUTION:
ECM00400
Do not attempt to run the outboard motor
until it has been completely inspected.
1. Manual valve screw
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							Consumer information
68
EMU29811
Important warranty information for U.S.A. and Canada
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							Consumer information
69
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							Consumer information
70
EMU29830
YAMAHA MOTOR CORPORATION, U.S.A.
 FOUR-STROKE OUTBOARD MOTOR
 THREE-YEAR LIMITED WARRANTY
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							Consumer information
71
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							Consumer information
72
EMU29841
IMPORTANT WARRANTY INFORMATION IF YOU USE YOUR 
YAMAHA OUTSIDE THE USA OR CANADA
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							May 2005–4.3 × 1 CR Printed in Japan
Printed on recycled paper
YAMAHA MOTOR CORPORATION, USA