2003 YAMAHA FX Owners Manual

4-10
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EJU01816
Inspecting the fuel system
WARNING@ Gasoline is highly flammable and explo-
sive. Failure to check for and repair any
fuel leakage could result in fire or explo-
sion. A fire or explosion can cause
severe injury or death. Shut off the
engine. Do not smoke. Avoid spilling
gasoline.
Fuel in hose is pressurized.
Fuel can spray out and cause injury or a
fire hazard if fuel line is disconnected.
Do not attempt to run engine with fuel
line disconnected.
Check the fuel system for leaks, cracks,
or malfunctions. If any problem is found,
consult a Yamaha dealer.
Check:

Fuel tank for water or dirt.

Fuel tank cap (seal) for damage.

Fuel tank for damage, cracks or leakage.

Fuel hose joint for leakage.

Fuel hose for cracks or other damage.

Air bleeding passages for leakage.
EJU01841
Fuel tank
Check the fuel tank 1 for leakage or
water in the tank. If water is found in the fuel
system or if the fuel tank needs to be
cleaned, have a Yamaha dealer service the
watercraft.
UF1B71.book Page 10 Tuesday, November 12, 2002 4:17 PM

4-11
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EJU20150
Changing the engine oil
WARNING@ Engine oil is extremely hot immediately
after the engine is turned off. Coming
into contact with or getting any engine
oil on your clothes could result in burns.
@
CAUTION:@
Do not run the engine with too much or
not enough oil in the oil tank. Oil could
spray out or the engine could be dam-
aged.

Be sure to change the engine oil after
the first 10 hours of operation, and
every 100 hours thereafter or at the
start of a new season, otherwise the
engine will wear quickly.
The oil filter should be replaced every
two years or every 200 hours of opera-
tion. Have a Yamaha dealer replace the
oil filter if necessary.
@
It is recommended to have a Yamaha
dealer change the engine oil. However, if
you choose to change the oil on your own
consult a Yamaha dealer.
NOTE:@ Dispose of used oil according to local regu-
lations.
@
Recommended engine oil:
See page 3-3.
Oil quantity:
With oil filter replacement:
2.2 L (2.3 US qt, 1.9 Imp qt)
Without oil filter replacement:
2.0 L (2.1 US qt, 1.8 Imp qt)
Total amount:
4.3 L (4.5 US qt, 3.8 Imp qt)
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4-12
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CAUTION:@ If oil is leaking or the oil pressure warn-
ing indicator comes on when the engine
is running, immediately turn the engine
off and have a Yamaha dealer check the
watercraft. Continuing to operate the
engine under such conditions could
cause severe engine damage.
@
UF1B71.book Page 12 Tuesday, November 12, 2002 4:17 PM

4-13
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EJU01819
Checking the air filter element
The air filter element should be checked
every 12 months or every 100 hours of oper-
ation.
To check the air filter:
1. Remove the rear and front seats. (See
pages 2-5 and 2-6 for seat removal and
installation procedures.)
2. Remove the air filter case cover
screws1, slide the locks 2 open, and
then remove the case cover.
3. Remove the air filter element and check
it for dirt and oil. Replace the air filter ele-
ment if there is any oil buildup, or every
2 years or every 200 hours of operation.
4. Install the air filter element in the air filter
case, and then install the case cover.
CAUTION:@
Make sure that the air filter element is
installed in the filter case properly.

Do not start the engine with the air fil-
ter element removed, otherwise the
pistons and cylinders could be dam-
aged.

If cleaning the air filter element, use
cold or lukewarm water and let it air
dry completely. Do not use detergent
or solvent to clean the air filter ele-
ment, or dry it with heat or com-
pressed air, otherwise it could be
damaged.
UF1B71.book Page 13 Tuesday, November 12, 2002 4:17 PM

4-14
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EJU01897
Inspecting the jet thrust nozzle
angle
Check for smooth operation of the handle-
bars and jet thrust nozzle.
Turn the handlebars as far as possible to
the right and left and check that the distance
between the jet thrust nozzle and the
bracket of the reverse gate are equal on
right and left sides.
If steering is stiff or misadjusted, have a
Yamaha dealer service it.
EJU01852
Inspecting the shift cable
Place the shift lever in the reverse posi-
tion.
Make sure that the reverse gate makes
contact with the stopper 1 on the bracket,
and that the arm 2 makes contact with the
reverse gate.
If the reverse gate does not reach the cor-
rect positions, have a Yamaha dealer ser-
vice it.
EJU01104
Inspecting and adjusting the
throttle cable
Check that the throttle cable moves back
to the set position smoothly and that free
play is within specification.
1. Squeeze and release the throttle lever. If
the lever does not return smoothly, have
a Yamaha dealer service it.
2. Adjust free play a by loosening the lock-
nut 1 and turning the adjuster 2. Distance A and B: A = B
Throttle lever free play:
4–7 mm (0.16–0.28 in)
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4-15
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EJU01842
Inspecting the QSTS
mechanism
Check that the shift lock lever moves back
to the lock position smoothly, that the QSTS
selector locks and unlocks properly, and that
the jet thrust nozzle moves up or down.
1. Squeeze and release the shift lock lever.
2. Check that the QSTS selector locks
when the lever is released.
3. Check that the selector turns smoothly
when the lever is squeezed and held in
place.
4. Check that the angle of the jet thrust
nozzle changes when the selector is
shifted from neutral to bow up or bow
down.
If the mechanism does not work properly,
have a Yamaha dealer service it.
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4-16
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EJU18201
Cleaning and adjusting the
spark plugs
The spark plug is an important engine
component and is easy to inspect. The con-
dition of the spark plug can indicate some-
thing about the condition of the engine. For
example, if one spark plug shows a distinctly
different color, the engine could be defec-
tive. Do not attempt to diagnose any prob-
lems yourself. Have a Yamaha dealer
service the watercraft.
Remove and inspect the spark plug peri-
odically; heat and deposits will cause the
spark plug to slowly break down and erode.
If electrode erosion becomes excessive, or if
carbon and other deposits are excessive,
replace the spark plug with the specified
plug.
Removing a spark plug:
1. Remove the air filter case cover and air
filter element. (See page 4-13 for air filter
removal and installation procedures.)
2. Remove the spark plug.
Measure the spark plug gap a with a
wire thickness gauge. Replace the spark
plugs or adjust the gap to specification if
necessary.Specified spark plug: NGK CR9EB
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
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4-17
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To install the spark plug:
1. Clean the gasket surface.
2. Wipe any dirt from the threads of the
spark plug.
3. Screw the spark plug to the correct
torque.
NOTE:@
Wipe off any water on the spark plug or
inside the cap before installing the spark
plug cap. Push the spark plug cap down
until it is securely installed.

If a torque wrench is not available when
you are fitting a new spark plug, a good
estimate of the correct torque is 1/4 turn
to 1/2 turn past finger tight with the spark
plug wrench included in the tool kit. Have
the spark plug adjusted to the correct
torque with a torque wrench as soon as
possible.
@
WARNING@ Be careful not to damage the insulator
when removing or installing a spark plug.
A damaged insulator could allow sparks
to escape, which could lead to explosion
or fire.
@
4. Install the air filter element in the air filter
case, and then install the air filter case
cover. Spark plug tightening torque:
12.5 N·m (1.25 kgf·m, 9 ft·lb)
UF1B71.book Page 17 Tuesday, November 12, 2002 4:17 PM