Yamaha F 25 Manual

Maintenance
36
EMU28874Maintenance chart (additional)
EMU28931Greasing
Yamaha marine grease (Water resistant grease)
EMU28952Cleaning 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 orfire.
The spark plug is an important engine compo-
nent and is easy to inspect. The condition of
the spark plug can indicate something about
the condition of the engine....

Maintenance
37
problem in that cylinder. Do not attempt to di-
agnose any problems yourself. Instead, take
the outboard motor to a Yamaha dealer. You
should periodically remove and inspect the
spark plug because heat and deposits will
cause the spark plug to slowly break down
and erode. If electrode erosion becomes ex-
cessive, or if carbon and other deposits are
excessive, you should replace the spark plug
with another of the correct type.
Before fitting the spark plug, measure the
electrode gap with a...

Maintenance
38

Fuel line cracks or other damage

Fuel connector leakageEMU29041Inspecting 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 flush-
ing attachment or test tank can be used.
A diagnostic tachometer should be used for
this procedure....

Maintenance
39
2. Prepare a suitable container that holds a
larger amount than the engine oil capaci-
ty. Loosen and remove the drain screw
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...

Maintenance
40
with oil if it is below the lower mark, or
drain to the specified level if it is above
the upper mark.
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.
EMU29112Checking wiring and connectors

Check that each grounding wire is properly
secured.

Check that each connector is engaged se-
curely....

Maintenance
41
Checkpoints

Check each of the propeller blades for
wear, erosion from cavitation or ventilation,
or other damage.

Check the propeller shaft for damage.

Check the splines / shear pin for wear or
damage.

Check for fish line tangled around the pro-
peller shaft.

Check the propeller shaft oil seal for dam-
age.
NOTE:
If the shear pin equipped: it is designed to
break if the propeller hits a hard underwater
obstacle to help protect the propeller and
drive mechanism. The propeller will then...

Maintenance
42
2. Install the spacer (if equipped), thrust
washer, and propeller on the propeller
shaft.
3. Install the spacer (if equipped) and the
washer. Tighten the propeller nut until
there is no forward-and-backward move-
ment.
4. Align the propeller nut with the propeller
shaft hole. Insert a new cotter pin in the
hole and bend the cotter pin ends.
NOTE:
If the propeller nut does not align with the pro-
peller shaft hole after tightening it, loosen the
nut until it aligns with the hole....

Maintenance
43
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.
EMU29312Inspecting and replacing anode(s)
Yamaha outboard motors are protected from
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...

Maintenance
44
U69M15E0.book  Page 44  Wednesday, April 5, 2006  4:48 PM 

Trouble Recovery
45
EMU29424
Troubleshooting
A problem in the fuel, compression, or ignition
systems can cause poor starting, loss of pow-
er, or other problems. This section describes
basic checks and possible remedies, and cov-
ers 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 flash-
ing, consult your Yamaha dealer.
Starter will not operate.
Q. Is battery...