Yamaha F50 Manual

							 
35 
Operation 
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
transducers) can create airborne water
spray while the boat is cruising. Severe
engine damage may result if the motor is
operated continuously in the presence of 
airborne 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 wa-
ter entry into the powerhead, when water
rises due to waves when the outboard is not 
running. 
EMU26910 
Mounting 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 capac-
ity 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 mo-
tor 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 experi-
enced 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. 
EMU26930 
Mounting 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 
1. Center line (keel line)
ZMU017601 
						

							 
Operation 
36 
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 deter-
mine the optimum mounting height. Con-
sult your Yamaha dealer or boat
manufacturer for further information on de-
termining the proper mounting height. 
 
For instructions on setting the trim angle of 
the outboard motor, see page 45. 
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 enginelife.
CAUTION:
 
ECM00800  
Failure to follow the break-in procedure
could result in reduced engine life or 
even severe engine damage. 
EMU27081 
Procedure for 4-stroke models 
Run the engine under load (in gear with a
propeller 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 out-
board motor. Otherwise an accident 
could occur.
CAUTION:
 
ECM00120  
Do not start the engine out of water. Over-
heating and serious engine damage can 
occur. 
EMU31550 
Fuel 
 
Check to be sure you have plenty of fuel
for your trip. 
 
Make sure there are no fuel leaks or gaso-
ZMU01762 
						

							 
Operation 
37 
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). 
 
Check the water in the fuel filter with the
water 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. 
EMU27130 
Controls 
 
Check throttle, shift, and steering for prop-
er operation before starting the engine. 
 
The controls should work smoothly, with-
out 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. 
EMU27150 
Engine 
 
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. 
EMU27163 
Checking 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 upperand 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. 
EMU27433 
Filling fuel
WARNING
 
EWM00060  
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other 
sources of ignition. 
1. Oil dipstick
1. Lower level mark
2. Oil dipstick
3. Upper level mark
1
ZMU05089
132
ZMU05091 
						

							 
Operation 
38 
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. 
EMU27270 
Ring Free Fuel Additive 
Gasoline is a precise blend of many different
substances, each chosen to give certain
characteristics. Gasoline blends have been
changing in recent years in response to con-
cerns about pollution and resulting emis-
sions regulations. One of the most obvious
changes has been the elimination of lead
from most fuels.
As gasoline has changed, the amount of ad-
ditives such as aromatics and oxygenates
has increased. These additives are impor-
tant for the engines in passenger cars, but
they can have detrimental effects in marine
engines, because of increased deposits in
the combustion chamber. When enough de-
posits collect, piston rings begin sticking.
Performance drops and engine wear in-
creases dramatically.
While many additives available may reduce
deposits, Yamaha recommends the use of 
Ring Free Fuel Additive 
, available from
your Yamaha dealer.  
Ring Free Fuel Addi-tive 
 has repeatedly proven its ability to clean
combustion deposits from inside the engine,
notably the critical piston-ring-land area, and
fuel system components. Follow product la-
beling for use instructions. 
EMU27450 
Operating engine 
EMU27461 
Feeding fuel (portable tank)
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 loosen-
ing the air vent screw. 
 
This product emits exhaust gases
which contain carbon monoxide, a col-
orless, odorless gas which could cause
brain damage or death when inhaled.
Symptoms include nausea, dizziness,
and drowsiness. Keep cockpit and cab-
in areas well ventilated. Avoid blocking 
exhaust outlets. 
1. If there is an air vent screw on the fuel
tank cap, loosen it 2 or 3 turns. Fuel tank capacity:
24 L (6.34 US gal) (5.28 Imp.gal)
ZMU02834 
						

							 
Operation 
39 
2. If there is a fuel joint on the motor, firmly
connect the fuel line to the joint. Then
firmly connect the other end of the fuel
line to the joint on the fuel tank.
3. If a steering friction adjuster is provided
on your outboard motor, securely attach
the fuel line to the fuel line clamp.
NOTE:
 
During engine operation place the tank hori-
zontally, otherwise fuel cannot be drawn 
from the fuel tank.
4. Squeeze the primer pump with the outlet
end up until you feel it become firm. 
EMU27490 
Starting engine 
EMU27592 
Electric start / prime start models 
1. Place the gear shift lever in neutral.
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
ZMU02295
ZMU03679
ZMU02024
ZMU02025 
						

							 
Operation 
40 
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 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. 
3. Place the throttle grip in the “”
(start) position. After the engine starts,
return the throttle to the fully closed po-
sition.
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 and allow it to re-
turn 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 discharged, thus making it im-
possible 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.
NOTE:
 
 
When the engine is cold, it needs to be
warmed up. For further information, see
page 42. 
 
If the engine is warm and fails to start,
open the throttle slightly and try to start the
engine again. If the engine still fails to 
start, see page 73. 
EMU27662 
Electric start and remote control models 
1. Place the remote control lever in neutral. 
						

							 
Operation 
41
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 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. 
3. Turn the main switch to “” (on).
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 and allow it to re-
turn 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 discharged, thus making it im-
possible 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 
						

							 
Operation 
42 
again.
NOTE:
 
 
When the engine is cold, it needs to be
warmed up. For further information, see
page 42. 
 
If the engine is warm and fails to start,
open the throttle slightly and try to start the
engine again. If the engine still fails to 
start, see page 73. 
EMU27670 
Warming up engine 
EMU27710 
Manual 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 in-
dicator goes off after starting the engine.
3. Check for a steady flow of water from the
cooling water pilot hole.
CAUTION:
 
ECM00210  
 
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 pi-
lot hole shows that the water pump is
pumping water through the cooling
passages. If water is not flowing out of
the pilot hole at all times while the en-
gine is running, overheating and seri-
ous damage could occur. Stop the
engine and check whether the cooling
water inlet on the lower case or thecooling water pilot hole is blocked.
Consult your Yamaha dealer if the prob- 
lem cannot be located and corrected. 
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 
engine idles (or runs at low speeds). 
EMU27764 
Forward (tiller handle and remote 
control models) 
Tiller handle models
1. Place the throttle grip in the fully closed
position.
ZMU05092 
						

							 
Operation 
43 
2. Move the gear shift lever quickly and
firmly from neutral to forward.
Remote control models
1. Pull up the neutral interlock trigger (if
equipped) and move the remote control
lever quickly and firmly from neutral to
forward.
 
EMU27785 
Reverse (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. Oth-
erwise the boat could become unstable,
which could result in loss of control and 
an accident. 
Tiller handle models
1. Place the throttle grip in the fully closed
position.
2. Move the gear shift lever quickly and
firmly from neutral to reverse.
Remote control models
1. Pull up the neutral interlock trigger (if
equipped) and move the remote control
lever quickly and firmly from neutral to
reverse. 
						

							 
Operation 
44 
EMU30880 
Trolling 
EMU30890 
Adjusting trolling speed 
The trolling speed on outboard motors
equipped with the variable trolling RPM
switches can be adjusted approximately 50
r/min with each press of a switch.
To increase the trolling speed, press the “”
switch.
To decrease the trolling speed, press the
“” switch.
NOTE:
 
 
The trolling speed changes approximately
50 r/min each time a switch is pressed. 
 
If the trolling speed has been adjusted, the
engine returns to the normal trolling speed
when the engine is stopped and restartedor when the engine speed exceeds ap- 
proximately 3000 r/min. 
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. 
EMU27844 
Procedure 
1. Push and hold the engine stop button or
turn the main switch to “” (off).
2. After stopping the engine, disconnect
the fuel line if there is a fuel joint on the
outboard motor. 
1. “” switch
2. “” switch