Yamaha F50 Manual

 
Maintenance 
65 
7. Dispose of used oil according to local
regulations.
NOTE:
 
 
For more information on the disposal of
used oil, consult your Yamaha dealer. 
 
Change the oil more often when operating
the engine under adverse conditions such 
as extended trolling. 
EMU29112 
Checking wiring and connectors 
 
Check that each grounding wire is properly
secured. 
 
Check that each connector is engaged se-
curely. 
EMU29120 
Exhaust leakage 
Start the engine and check that no exhaust
leaks from the...

 
Maintenance 
66
NOTE:
 
Consult your Yamaha dealer if any operation 
is abnormal. 
EMU29171 
Checking propeller
WARNING
 
EWM00321  
You could be seriously injured if the en-
gine accidentally starts when you are
near the propeller. 
 
Before inspecting, removing, or install-
ing the propeller, remove the spark
plug caps from the spark plugs. Also,
place the shift control in neutral, turn
the main switch to “” (off) and re-
move the key, and remove the lanyard
from the engine stop switch. Turn off
the...

 
Maintenance 
67 
EMU30660 
Removing the propeller 
EMU29194 
Spline models 
1. Straighten the cotter pin and pull it out
using a pair of pliers.
2. Remove the propeller nut, washer, and
spacer (if equipped).3. Remove the propeller and thrust wash-
er. 
EMU30670 
Installing the Propeller 
EMU29231 
Spline models
CAUTION:
 
ECM00340  
 
Be sure to install the thrust washer be-
fore installing the propeller, otherwise
the lower case and propeller boss
could be damaged. 
 
Be sure to use a new cotter pin...

 
Maintenance 
68 
specified torque, tighten the nut further to 
align it with the hole. 
EMU29282 
Changing gear oil
WARNING
 
EWM00800  
 
Be sure the outboard motor is securely
fastened to the transom or a stable
stand. You could be severely injured if
the outboard motor falls on you. 
 
Never get under the lower unit while it
is tilted, even when the tilt support lever
or knob is locked. Severe injury could
occur if the outboard motor accidental- 
ly falls. 
1. Tilt the outboard motor so that the...

 
Maintenance 
69 
6. Put a new gasket on the oil level plug.
When the oil begins to flow out of the oil
level plug hole, insert and tighten the oil
level plug.
7. Put a new gasket on the gear oil drain
screw. Insert and tighten the gear oil
drain screw. 
EMU29302 
Cleaning fuel tank
WARNING
 
EWM00920  
Gasoline is highly flammable, and its va-
pors are flammable and explosive. 
 
If you have any question about properly
doing this procedure, consult your
Yamaha dealer. 
 
Keep away from sparks,...

 
Maintenance 
70 
corrosion by sacrificial anodes. Inspect the
external anodes periodically. Remove scales
from the surfaces of the anodes. Consult a
Yamaha dealer for replacement of external
anodes.
CAUTION:
 
ECM00720  
Do not paint anodes, as this would render 
them ineffective.
NOTE:
 
Inspect ground leads attached to external
anodes on equipped models. Consult a
Yamaha dealer for inspection and replace-
ment of internal anodes attached to the pow- 
er unit. 
EMU29320 
Checking battery (for electric...

 
Maintenance 
71 
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 rec-
ommended level when necessary. Top
up only with distilled...

 
Maintenance 
72 
EMU29370 
Disconnecting the battery 
Disconnect the BLACK cable from the NEG-
ATIVE (-) terminal first. Then disconnect the
RED cable from the POSITIVE (+) terminal. 
EMU29390 
Checking top cowling 
Check the fitting of the top cowling by push-
ing it with both hands. If it is loose have it re-
paired by your Yamaha dealer. 
EMU29400 
Coating the boat bottom 
A clean hull improves boat performance. The
boat bottom should be kept as clean of ma-
rine growth as possible. If necessary,...

 
73 
Trouble Recovery 
EMU29424 
Troubleshooting 
A problem in the fuel, compression, or igni-
tion systems can cause poor starting, loss of
power, or other problems. This section de-
scribes basic checks and possible remedies,
and covers 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
flashing, consult your Yamaha dealer. 
Starter will not operate. 
Q. Is...

 
Trouble Recovery 
74 
Q. Is fuel system obstructed?
A. Check for pinched or kinked fuel line or
other 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...