2003 YAMAHA SUPERJET service

4-1
E
EJU01087
Storage
WARNING@ Always place the fuel cock knob in the
“OFF” position when storing the water-
craft, otherwise fuel could leak out into
the engine or engine compartment,
which would create a fire hazard.
@
Storage for prolonged periods of time,
such as winter storage, requires preventa-
tive maintenance to ensure against deterio-
ration. It is advisable to have the watercraft
serviced by a Yamaha dealer prior to stor-
age. However, the following procedures can
be performed by the owner.
EJU01088
Flushing the cooling system
Flushing the cooling system is essential
to prevent the cooling system from being
clogged with salt, sand, or dirt.
CAUTION:@
Do not supply water to the cooling
water passages when the engine is not
running. The water could flow back
through the muffler into the crankcase
causing severe engine damage.

Do not run the engine for more 15 sec-
onds without supplying water, other-
wise the engine may overheat.
@
UF1N71.book Page 1 Tuesday, June 4, 2002 3:34 PM

4-7
E
EJU01094
Maintenance and
adjustments
Periodic inspection, adjustment and lubri-
cation will keep your watercraft in the safest
and most efficient condition possible. Safety
is an obligation of the watercraft owner. The
most important points of watercraft inspec-
tion, adjustment and lubrication are
explained on the following pages.
See your Yamaha dealer for genuine
Yamaha replacement parts and optional
accessories designed for your watercraft.
Remember that failures that are the result
of the installation of parts or accessories
which are not qualitatively equivalent to gen-
uine Yamaha parts are not covered by the
limited warranty.
WARNING@
Be sure to turn off the engine when
you perform maintenance unless oth-
erwise specified, otherwise an acci-
dent or injury could result from
unexpected operation, moving parts,
or electric shock. If the owner is not
familiar with watercraft servicing, this
work should be done by a Yamaha
dealer. Improperly serviced compo-
nents could fail or stop operating cor-
rectly, which could result in an
accident.

Modifications to this watercraft not
approved by Yamaha may cause loss
of performance or excessive noise, or
render it unsafe for use. Consult a
Yamaha dealer before attempting any
changes.
@
UF1N71.book Page 7 Tuesday, June 4, 2002 3:34 PM

4-8
E
EJU01301
Owner’s/Operator’s Manual
and tool kit
It is advisable always to carry the
Owner’s/Operator’s Manual and tool kit with
you whenever you use the watercraft. For
your convenience, a storage pouch 1 is
provided on the watercraft for the manual
and tool kit.
NOTE:@ To protect these materials from water dam-
age, it would be a good idea to put them in a
waterproof bag.
@
The service information included in this
manual is intended to provide you, the
owner, with the necessary information for
completing your own preventive mainte-
nance and minor repairs. The tools provided
in the tool kit 2 are sufficient for this pur-
pose, except that a torque wrench may also
be necessary to tighten nuts and bolts.
UF1N71.book Page 8 Tuesday, June 4, 2002 3:34 PM

4-11
E
EJU01953
Fuel filter
This watercraft is equipped with a one-
piece, disposable fuel filter 1. The fuel filter
should be replaced after the initial 10 hours
or first month of operation and every
200 hours or 24 months thereafter, or if
water is found in the filter. Have a Yamaha
dealer replace the fuel filter if necessary.
WARNING@ Do not try to replace the fuel filter your-
self. An incorrectly installed filter can
leak gasoline, which could lead to fire or
explosion. If necessary, have a Yamaha
dealer replace the fuel filter.
@
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.
UF1N71.book Page 11 Tuesday, June 4, 2002 3:34 PM

4-12
E
EJU01891
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 hull
are equal on right and left sides.
If steering is stiff or misadjusted, have a
Yamaha dealer service it.Distance A and B: A=B
EJU01375
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.
Throttle lever free play:
7–10 mm (0.28–0.39 in)
UF1N71.book Page 12 Tuesday, June 4, 2002 3:34 PM

4-13
E
EJU01343
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 the center electrode porcelain is
very white, this could indicate an intake air
leak or carburetion problem in that cylinder.
Do not attempt to diagnose any problems
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.
Measure the spark plug gap a with a
wire thickness gauge before installing the
spark plug. Adjust the gap to specification if
necessary.
To reinstall 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. Standard spark plug: BR7HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Spark plug torque:
25 N·m (2.5 kgf·m, 18 ft·lb)
UF1N71.book Page 13 Tuesday, June 4, 2002 3:34 PM

5-1
E
EJU01116
Troubleshooting
If you have any trouble with your watercraft, use this section to check for the possible
cause.
If you cannot find the cause, or if the procedure for replacement or repair is not described
in this Owner’s/Operator’s Manual, have a Yamaha dealer perform the necessary service.
EJU01367
Troubleshooting chart
TROUBLE POSSIBLE CAUSE REMEDY PAGE
Engine does not
startStarter motor does not turn over
Engine shut-
off switch Clip not in place Install clip
2-5
Fuse Burned out Replace fuse and check
wiring4-20
Battery Run down Recharge 4-17
Poor terminal connec-
tionsTighten as required
4-17
Starter motor Faulty Have serviced by
Yamaha dealer—
Starter motor turns over
Fuel cock Turned to “OFF”Turn fuel cock knob to
“ON”2-4
Fuel Empty Refill as soon as possi-
ble3-4
Stale or contaminated Have serviced by
Yamaha dealer4-10
Fuel tank Water or dirt present Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Clean or replace 4-13
Spark plug cap Not connected or loose Connect properly 4-13
Crankcase Filled with water Crank engine with plug
out until clean5-7
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer4-11
Choke Knob moves back on
its ownTighten choke knob
adjusting nut4-16
UF1N71.book Page 1 Tuesday, June 4, 2002 3:34 PM

5-2
E
Engine runs irregu-
larly or stallsFuel Empty Refill as soon as possi-
ble3-4
Stale or contaminated Have serviced by
Yamaha dealer4-10
Too much oil in fuel
mixing ratioCorrect fuel-to-oil ratio
to 50:13-3
Choke Knob is left pulled Push fully in 2-6
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer4-11
Fuel tank Water or dirt present Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Replace 4-13
Incorrect heat range Replace 4-13
Gap incorrect Adjust 4-13
Spark plug cap Loose Connect properly 4-13
Cracked, torn or dam-
agedReplace
4-13
Electrical wir-
ingLoose electrical con-
nectionsTighten or connect
properly—
Carburetor Incorrect idle adjust-
mentAdjust idle
4-19
Clogged Have serviced by
Yamaha dealer4-19
Wate rcr af t slow or
loses powerCavitation Jet intake clogged Clean 5-3
Impeller damaged or
wornHave serviced by
Yamaha dealer5-3
Engine over-
heatedJet intake clogged Clean
5-3
Fuel filter Clogged Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Replace 4-13
Incorrect heat range Replace 4-13
Gap incorrect Adjust 4-13
Spark plug
capsLoose Connect properly
4-13
Fuel Stale or contaminated Have serviced by
Yamaha dealer4-10 TROUBLE POSSIBLE CAUSE REMEDY PAGE
UF1N71.book Page 2 Tuesday, June 4, 2002 3:34 PM