Yamaha F50 Manual

 
Maintenance 
55 
5. Cooling system flushing is essential to
prevent the cooling system from clog-
ging up with salt, sand, or dirt. In addi-
tion, fogging/lubricating of the engine is
mandatory to prevent excessive engine
damage due to rust. Perform the flush-
ing and fogging at the same time.
WARNING
 
EWM00090  
 
Do not touch or remove electrical parts
when starting or during operation. 
 
Keep hands, hair, and clothes away
from the flywheel and other rotating 
parts while the engine is running....

 
Maintenance 
56 
EMU28430 
Battery care
WARNING
 
EWM00330  
Battery electrolytic fluid is dangerous; it
contains sulfuric acid and therefore is
poisonous and highly caustic.
Always follow these preventive mea-
sures: 
 
Avoid bodily contact with electrolytic
fluid as it can cause severe burns or
permanent eye injury. 
 
Wear protective eye gear when han-
dling or working near batteries.
Antidote (EXTERNAL): 
 
SKIN - Flush with water. 
 
EYES - Flush with water for 15 minutes
and get immediate...

 
Maintenance 
57 
2. Screw the garden hose adapter onto a
garden hose, which is connected to a
fresh water supply, and then connect it
to the garden hose connector.
3. With the engine off, turn on the water tap
and let the water flush through the cool-
ing passages for about 15 minutes. Turn
off the water and disconnect the garden
hose adapter from the garden hose con-
nector.
4. Reinstall the garden hose connector
onto the fitting on the bottom cowling.
Tighten the connector securely.
CAUTION:...

 
Maintenance 
58 
EMU28486 
Periodic maintenance
WARNING
 
EWM01070  
Be sure to turn off the engine when you
perform maintenance unless otherwise
specified. If you or the owner is not famil-
iar with machine servicing, this work
should be done by your Yamaha dealer or 
other qualified mechanic.
Maintenance, replacement, or repair of
the emission control devices and sys-
tems may be performed by any marine
engine repair establishment or individual.
All warranty repairs, however, including
those to the...

 
Maintenance 
59 
EMU28522 
Maintenance chart 
Frequency of maintenance operations may be adjusted according to the operating condi-
tions, but the following table gives general guidelines. Refer to the sections in this chapter for
explanations of each owner-specific action.
NOTE:
 
When operating in salt water, turbid or muddy water, the engine should be flushed with clean 
water after each use.
The “” symbol indicates the check-ups which you may carry out yourself.
The “” symbol indicates work to be...

 
Maintenance 
60 
EMU28874 
Maintenance chart (additional) 
Engine oil Inspection / change
Oil filter (cartridge) Change
Spark plug(s)Cleaning / adjustment / 
replacement
Timing beltInspection / replace-
ment
Valve clearance (OHC, 
OHV)Inspection / adjustment 
Item ActionsEvery
500 hours (2.5 years) 1000 hours (5 years) 
Timing belt Replacement
Fuel filter (vapor sepa-
rator tank)Replacement
Anode(s) (exhaust 
cover, cover joint)Replacement
Exhaust guide, exhaust 
manifoldInspection / replace-
ment 
Item...

 
Maintenance 
61 
EMU28931 
Greasing 
Yamaha marine grease (Water resistant grease) 
F50, T50, F60, T60 
EMU28952 
Cleaning and adjusting spark plug
WARNING
 
EWM00560  
When removing or installing a spark plug,
be careful not to damage the insulator. A
damaged insulator could allow external
sparks, which could lead to explosion or 
fire. 
The spark plug is an important engine com-
ponent and is easy to inspect. The condition
of the spark plug can indicate something
about the condition of the engine....

 
Maintenance 
62 
adjust the gap to specification if necessary.
When fitting the plug, always clean the gas-
ket surface and use a new gasket. Wipe off
any dirt from the threads and screw in the
spark plug to the correct torque.
NOTE:
 
If a torque-wrench is not available when you
are fitting a spark plug, a good estimate of
the correct torque is 1/4 to 1/2 a turn past fin-
ger-tight. Have the spark plug adjusted to the
correct torque as soon as possible with a 
torque-wrench. 
EMU28962 
Checking fuel...

 
Maintenance 
63 
EMU29041 
Inspecting idling speed
WARNING
 
EWM00451  
 
Do not touch or remove electrical parts
when starting or during operation. 
 
Keep hands, hair, and clothes away
from the flywheel and other rotating 
parts while the engine is running.
CAUTION:
 
ECM00490  
This procedure must be performed while
the outboard motor is in the water. A
flushing attachment or test tank can be 
used. 
A diagnostic tachometer should be used for
this procedure. Results may vary depending
on whether...

 
Maintenance 
64 
while holding the container under the
drain hole. Then remove the oil filler cap.
Let the oil drain completely. Wipe up any
spilled oil immediately.
3. Put a new gasket on the oil drain screw.
Apply a light coat of oil to the gasket and
install the drain screw.
NOTE:
 
If a torque wrench is not available when you
are installing the drain screw, finger tighten
the screw just until the gasket comes into
contact with the surface of the drain hole.
Then tighten 1/4 to 1/2 turn more....