Yamaha F250 Owners Manual

							Maintenance
55
CAUTION:
ECM01510

Do not use any tools to remove or install
the spark plug cap, otherwise the igni-
tion coil coupler may get damaged. The
spark plug cap may be difficult to re-
move because the rubber seal on the
end of the cap fits tightly. To remove the
spark plug cap, simply twist it back and
forth while pulling it out; to install it,
twist it back and forth while pushing it
in.

Be sure to use the specified spark plug,
otherwise the engine may not operate
properly.
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. For example, if the
center electrode porcelain is very white, this
could indicate an intake air leak or carburetion
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.
1. Remove the bolts that are securing the
ignition coil cover, and then remove the
cover.2. Remove the bolts that are securing the
spark plug cap, and then remove the cap.
3. Remove the spark plug. If electrode ero-
sion becomes excessive, or if carbon and
other deposits are excessive, you should
replace the spark plug with another of the
correct type.
4. Before fitting the spark plug, measure the
electrode gap with a wire thickness
gauge; adjust the gap to specification if
necessary.
Standard spark plug:
LFR6A-11
1. Spark plug gap
2. Spark plug part number
3. Spark plug I.D. mark (NGK)
Spark plug gap:
1.0–1.1 mm (0.039–0.043 in)
U6P213E0.book  Page 55  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
56
5. When fitting the plug, wipe off any dirt
from the threads, and then screw it in 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 turn past finger-
tight. Have the spark plug adjusted to the cor-
rect torque as soon as possible with a torque-
wrench.
6. Install the spark plug cap and tighten the
bolts.
7. Install the ignition coil cover and tighten
the bolts.
EMU28962Checking fuel system
WARNING
EWM00060
Gasoline and its vapors are highly flam-
mable and explosive. Keep away from
sparks, cigarettes, flames, or other sourc-
es of ignition.
WARNING
EWM00910
Leaking fuel can result in fire or explosion.

Check for fuel leakage regularly.

If any fuel leakage is found, the fuel sys-
tem must be repaired by a qualified me-
chanic. Improper repairs can make the
outboard unsafe to operate.
Check the fuel lines for leaks, crack, or mal-
function. If a problem is found, your Yamaha
dealer or other qualified mechanic should re-
pair it immediately.Checkpoints

Fuel system parts leakage

Fuel line joint leakage

Fuel line cracks or other damage

Fuel connector leakageEMU29087Changing engine oil
WARNING
EWM00760

Avoid draining the engine oil immediate-
ly after stopping the engine. The oil is
hot and should be handled with care to
avoid burns.

Be sure the outboard motor is securely
fastened to the transom or a stable
stand.
Spark plug torque:
25.0 Nm (18.4 ft-lb) (2.55 kgf-m)
U6P213E0.book  Page 56  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
57
CAUTION:
ECM01240
Change the engine oil after the first 10
hours of operation, and every 100 hours or
at 6-month intervals thereafter. Otherwise
the engine will wear quickly.
NOTE:
Change the engine oil when the oil is still
warm.
The engine oil can be extracted with an oil
changer (recommended), or drained by re-
moving the oil drain screw.
Extracting the oil with an oil changer (normal
oil change)
1. Put the outboard motor in an upright po-
sition (not tilted).
2. Pull out the dipstick and use the oil
changer to extract the oil.3. Remove the oil filler cap. Add the correct
amount of oil through the filler hole, and
install the filler cap.
CAUTION:
ECM00970

Do not overfill the oil, and be sure the
outboard motor is upright (not tilted)
when checking and changing the engine
oil.

If the oil level is above the upper level
mark, drain until the level meets the
specified capacity. Overfilling the oil
could cause leakage or damage.
4. Remove oil dipstick and wipe it clean.
5. Completely insert the dipstick and re-
move it again.
6. Check the oil level using the dipstick to be
sure the level falls between the upper lev-
el mark “” and lower level mark “” . Fill
with oil if it is below the lower level mark
“”, or drain to the specified level if it is
above the upper level mark “” .
1. Oil filler cap
Recommended engine oil:
4-stroke outboard motor oil
Engine oil quantity (excluding oil filter):
5.6 L (5.92 US qt) (4.93 Imp.qt)
U6P213E0.book  Page 57  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
58
7. Start the engine and make sure that the
low oil pressure warning indicator re-
mains off. Also, make sure that there are
no oil leaks.
CAUTION:
ECM01620
If the low oil pressure warning indicator
comes on or if there are oil leaks, stop the
engine and find the cause. Continued op-
eration with a problem could cause severe
engine damage. Consult your Yamaha
dealer if the problem cannot be located
and corrected.
8. Turn off the engine and wait 3 minutes.
Recheck the oil level using the dipstick to
be sure the level falls between the upper
level mark “” and lower level mark “” .
Fill with oil if it is below the lower level
mark “”, or drain to the specified level if
it is above the upper level mark “” .9. 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.
Draining the oil by removing the oil drain
screw
1. Remove the four bolts to remove the
apron from the starboard side.
1. Oil dipstick
2. Lower level mark “”
3. Upper level mark “”1. Oil dipstick
2. Lower level mark “”
3. Upper level mark “”
U6P213E0.book  Page 58  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
59
2. Tilt the outboard motor 5–10 degrees up,
then turn it entirely to the starboard side
until the drain screw is directly below.
3. 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. Let the oil drain completely.
Wipe up any spilled oil immediately.
4. 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. Tighten
the drain screw to the correct torque with a
torque wrench as soon as possible.

Apply grease to the apron retaining bolts
before tightening them.
5. Add the engine oil and check the oil level.
Refer to steps 3 to 9 in the previous oil
changing procedure with the oil changer.
EMU29112Checking wiring and connectors

Check that each grounding wire is properly
secured.

Check that each connector is engaged se-
curely.
EMU29120Exhaust leakage
Start the engine and check that no exhaust
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder.
EMU29130Water leakage
Start the engine and check that no water
leaks from the joints between the exhaust
cover, cylinder head, and body cylinder.
EMU29140Engine oil leakage
Check for oil leaks on the around the engine.
NOTE:
If any leaks are found, consult your Yamaha
dealer.
1. Drain screw
Drain screw tightening torque:
28.0 Nm (20.7 ft-lb) (2.86 kgf-m)
U6P213E0.book  Page 59  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
60
EMU29153Checking power trim and tilt system
WARNING
EWM00430

Never get under the lower unit while it is
tilted, even when the tilt support lever is
locked. Severe injury could occur if the
outboard motor accidentally falls.

Make sure no one is under the outboard
motor before performing this test.
1. Check the power trim and tilt unit for any
sign of oil leaks.
2. Operate each of the power trim and tilt
switches on the remote control and en-
gine bottom cowling (if equipped) to
check that all switches work.
3. Tilt the outboard motor up and check that
the tilt rod and trim rods are extended
completely.
4. Use the tilt support lever to lock the motor
in the up position. Operate the tilt down
switch briefly so the motor is supported
by the tilt support lever.5. Check that the tilt rod and trim rods are
free of corrosion or other flaws.
6. Activate the tilt-down switch until the trim
rods have retracted completely into the
cylinders.
7. Activate the trim-up switch until the tilt rod
is fully extended. Unlock the tilt support
lever.
8. Tilt the outboard motor down. Check that
the tilt rod and trim rods operate smooth-
ly.
NOTE:
Consult your Yamaha dealer if any operation
is abnormal.
1. Tilt rod
2. Trim rods
1. Tilt support lever
U6P213E0.book  Page 60  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
61
EMU29171Checking 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 remove the key,
and remove the lanyard from the engine
stop switch. Turn off the battery cut-off
switch if your boat has one.

Do not use your hand to hold the propel-
ler when loosening or tightening the
propeller nut. Put a wood block between
the anti-cavitation plate and the propel-
ler to prevent the propeller from turning.
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 spin
freely on the shaft. If this happens, the shear
pin must be replaced.
ZMU01897
U6P213E0.book  Page 61  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
62
EMU30660Removing the propellerEMU29194Spline models
1. Straighten the cotter pin and pull it out us-
ing a pair of pliers.
2. Remove the propeller nut, washer, and
spacer (if equipped).
3. Remove the propeller and thrust washer.
EMU30670Installing the PropellerEMU29242Spline models
WARNING
EWM00770
On counter rotation models, be sure to
use a propeller intended for counterclock-
wise rotation. These propellers are identi-
fied with the letter “L” after the size
indication on the propeller. Otherwise the
boat could move in the opposite direction
from that expected.
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 and bend
the ends over securely. Otherwise the
propeller could come off during opera-
tion and be lost.
1. Apply Yamaha marine grease or a corro-
sion resistant grease to the propeller
shaft.
2. Install the thrust washer and propeller on
the propeller shaft.
3. Install the spacer and washer. Tighten
the propeller nut to the specified torque.
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 to the speci-
fied torque, tighten the nut further to align it
with the hole.
1. Cotter pin
2. Propeller nut
3. Washer
4. Spacer
5. Propeller
6. Thrust washer
Propeller nut tightening torque:
55.0 Nm (40.6 ft-lb) (5.61 kgf-m)
U6P213E0.book  Page 62  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
63
EMU31910Changing 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 oc-
cur if the outboard motor accidentally
falls.
1. Tilt the outboard motor so that the gear oil
drain screw is at the lowest point possi-
ble.
2. Place a suitable container under the gear
case.
3. Remove the cooling water inlet covers on
both sides of the gear case. Be careful
not to lose the bolt and nut.
4. Remove the gear oil drain screw and gas-
ket.
NOTE:

If a magnetic gear oil drain screw is
equipped, remove all metal particles from
the screw before installing it.

Always use new gaskets. Do not reuse the
removed gaskets.
5. Remove the oil level plug and gasket to
allow the oil to drain completely.
CAUTION:
ECM00710
Inspect the used oil after it has been
drained. If the oil is milky, water is getting
into the gear case which can cause gear
damage. Consult a Yamaha dealer for re-
pair of the lower unit seals.
1. Gear oil drain screw
2. Oil level plug
3. Gasket
U6P213E0.book  Page 63  Thursday, March 9, 2006  10:20 AM 
						

							Maintenance
64
NOTE:
For disposal of used oil, consult your Yamaha
dealer.
6. With the outboard motor in a vertical po-
sition, and using a flexible or pressurized
filling device, inject the gear oil into the
gear oil drain screw hole.
7. 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.
8. Put a new gasket on the gear oil drain
screw. Insert and tighten the gear oil
drain screw.
9. Securely install the cooling water inlet
covers on both sides of the gear case us-
ing the bolt and nut removed earlier.
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
anodes.
CAUTION:
ECM00720
Do not paint anodes, as this would render
them ineffective.
NOTE:
Inspect ground leads attached to external an-
odes on equipped models. Consult a Yamaha
dealer for inspection and replacement of inter-
nal anodes attached to the power unit.
Recommended gear oil:
Hypoid gear oil SAE#90
Gear oil quantity:
F250TR 918.0 cm³ (31.04 US oz) 
(32.38 Imp.oz)
LF250TR 803.0 cm³ (27.15 US oz) 
(28.32 Imp.oz)
U6P213E0.book  Page 64  Thursday, March 9, 2006  10:20 AM