Yamaha F50 Manual

							 
Trouble Recovery 
75 
A. Have serviced by a Yamaha dealer.
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 out-
board 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
other 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 bro-
ken 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. 
						

							 
Trouble Recovery 
76 
Q. Is fuel joint connection incorrect?
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 
emergency 
EMU29440 
Impact damage
WARNING
 
EWM00870  
The outboard motor can be seriouslydamaged 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 com-
ponents 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. 
EMU30680 
Replacing fuse 
If a fuse has blown, open the fuse holder and
remove the fuse with a fuse puller. 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. 
						

							 
Trouble Recovery 
77 
EMU29522 
Power 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. 
EMU31601 
Water 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
procedure. 
1. Fuse (20 A  
× 
 3, 30 A  
× 
 1)
2. Spare fuse (20 A  
× 
 3, 30 A  
× 
 1)
3. Fuse puller
3
2
1
1 2
ZMU05099
 
1. Manual valve screw
1
ZMU03668 
						

							 
Trouble Recovery 
78 
1. Stop the engine.
2. Remove the top cowling.
3. Remove the plastic tie.
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
housing.
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 soak-
ing 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 
1. Water separator warning indicator
1. Plastic tie
1
ZMU05475
 
1. Water detection switch coupler
1. Filter cup
2. Water detection switch lead
1
ZMU05476
1
2
ZMU05477 
						

							 
Trouble Recovery 
79 
the filter housing.
8. Connect the water detection switch cou-
pler securely until a click is heard.
9. Fasten the water detection switch lead
with the plastic tie.
10. Install the top cowling.
11. Start the engine and make sure that the
water separator warning indicator re-
mains off.
NOTE:
 
Have a Yamaha dealer inspect the outboard 
motor after returning to port. 
EMU29541 
Starter will not operate 
If the starter mechanism does not operate
(the engine cannot be cranked with the start-er), the engine can be started manually with
an emergency starter rope. However, the en-
gine cannot be started manually if the battery
voltage is low. If the battery is discharged to
9 volts or below, the electric fuel pump will
not operate.
WARNING
 
EWM01021  
 
Use this procedure only in an emergen-
cy to return to the nearest port for re-
pairs. 
 
When the emergency starter rope is
used to start the engine, the start-in-
gear protection device does not oper-
ate. Make sure the remote control lever
is in neutral. Otherwise the boat could
unexpectedly start to move, which
could result in an accident. 
 
Attach the engine stop switch lanyard
to a secure place on your clothing, or
your arm or leg while operating the
boat. 
 
Do not attach the lanyard to clothing
that could tear loose. Do not route the
cord where it could become entangled,
preventing it from functioning. 
 
Avoid accidentally pulling the lanyard
during normal operation. Loss of en-
gine 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. 
 
Make sure no one is standing behind
you when pulling the starter rope. It
could whip behind you and injure
someone. 
 
An unguarded, rotating flywheel is very
dangerous. Keep loose clothing and
other objects away when starting the
engine. Use the emergency starter rope 
1. Water detection switch coupler
1. Plastic tie
1
ZMU05509
1
ZMU05475 
						

							 
Trouble Recovery 
80 
only as instructed. Do not touch the fly-
wheel or other moving parts when the
engine is running. Do not install the
starter mechanism or top cowling after
the engine is running. 
 
Do not touch the ignition coil, spark
plug wire, spark plug cap, or other elec-
trical components when starting or op-
erating the motor. You could get an 
electrical shock. 
EMU29581 
Emergency starting engine 
1. Remove the top cowling.
2. Remove the flywheel cover.
3. Prepare the engine for starting. For fur-
ther information, see page 39. Be sure
the engine is in neutral and that the en-
gine stop switch lanyard lock plate is at-
tached to the engine stop switch.
4. Turn on the main switch.5. Insert the knotted end of the emergency
starter rope into the notch in the flywheel
rotor and wind the rope around the fly-
wheel several turns clockwise.
6. Give a strong pull straight out to crank
the engine. Repeat if necessary.
WARNING
 
EWM00620  
Do not install the top cowling when en- 
gine is running. 
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 immedi-
ately.
If you cannot immediately take the outboard
motor to a Yamaha dealer, follow the proce-
dure below in order to minimize engine dam-
age.
ZMU03670
ON START OFF
ZMU01906
ZMU03671 
						

							 
Trouble Recovery 
81 
EMU29790 
Procedure 
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. Feed fogging oil or engine oil through
the intake manifold and spark plug holes
while cranking with the emergency start-
er rope.
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. 
						

							 
82 
Consumer information 
EMU29811 
Important warranty information for U.S.A. and Canada 
						

							 
Consumer information 
83 
						

							 
Consumer information 
84 
EMU29830 
YAMAHA MOTOR CORPORATION, U.S.A.
 FOUR-STROKE OUTBOARD MOTOR
 THREE-YEAR LIMITED WARRANTY