2003 YAMAHA SUPERJET engine overheat

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2
EJU01007
FEATURES AND
FUNCTIONS
Location of main components .............. 2-1
Operation of controls and other
functions ................................................... 2-3
Hood ....................................................... 2-3
Fuel tank filler cap .................................. 2-4
Fuel cock knob ....................................... 2-4
Engine stop switch ................................. 2-5
Engine shut-off switch ............................ 2-5
Choke knob ............................................ 2-6
Throttle lever .......................................... 2-6
Start switch ............................................. 2-6
Cooling water pilot outlet ....................... 2-7
Steering system ..................................... 2-7
Steering pole .......................................... 2-8
Engine overheat warning system .......... 2-9
Storage pouch ...................................... 2-10
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2-9
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EJU01131
Engine overheat warning
system
This model is equipped with an engine
overheat warning system.
If the engine starts to overheat, the
engine speed will be limited to about
3,400 r/min.
When this occurs, check for water dis-
charge at the cooling water pilot outlet. If
there is no discharge of water, reduce the
engine speed and beach the watercraft, and
then check the intake grate and impeller for
clogging.
WARNING@ Before attempting to remove weeds or
debris from the intake grate or impeller,
shut the engine off and remove the clip
from the engine shut-off switch. Severe
injury or death could result from coming
in contact with the rotating parts of the
jet pump.
@
CAUTION:@ If you cannot locate and correct the
cause of the overheating, consult a
Yamaha dealer. Continuing to operate at
higher speeds could result in severe
engine damage.
@
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3-11
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EJU01058
Jet unit
Carefully check the jet intake for weeds,
debris, or anything else that might restrict
the intake of water. If the intake is clogged,
cavitation could occur, reducing jet thrust,
and possibly damaging the jet pump.
In some cases, the engine may overheat
because of lack of cooling water, and dam-
age to the engine could result. Engine cool-
ing water is fed to the engine by the jet
pump. (See page 5-3 for jet intake cleaning
procedures.)
WARNING@
Keep away from intake grate while
engine is on. Items such as long hair,
loose clothing, or PFD straps can
become entangled in moving parts
resulting in severe injury or drowning.

Stop the engine and remove the clip
from the engine shut-off switch before
removing any debris or weeds, which
may have collected around the jet
intake.
@
EJU01059
Engine shut-off cord (lanyard)
Check that the engine shut-off cord is not
frayed or broken. If the cord is damaged,
replace it; never try to repair it or tie it
together.
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3-26
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EJU01293
Capsized watercraft
If the watercraft capsizes, follow the pro-
cedures below carefully to prevent damage
or injury.
CAUTION:@ Make sure to remove the clip from the
engine shut-off switch, otherwise the
engine will overheat and damage may
occur.
@
1. Shut the engine off by removing the clip
from the engine shut-off switch.
2. Swim to the rear of the watercraft and
upright it by turning it clockwise only.
CAUTION:@ Do not turn the watercraft over counter-
clockwise, otherwise water may leak into
the carburetor and engine and cause
damage.
@
3. Start the engine, and then head for
shore to inspect the engine for water
damage.
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3-32
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CAUTION:@ Do not run the engine at full throttle or
for more than 15 seconds on land, other-
wise the engine may overheat and seize.
@
7. If the watercraft will be stored for a week
or more, lubricate internal engine com-
ponents to help prevent corrosion. (See
page 4-3 for lubrication procedures.)
8. Rinse the engine and engine compart-
ment with a small amount of water.
CAUTION:@ Do not use high pressure when rinsing
the engine or engine compartment as
severe damage could result.
@
9. Wipe the engine and engine compart-
ment dry with a clean cloth (repeat
step 3, if necessary).
10. Wipe the hull, steering pole, handlebars,
and jet unit dry with a clean cloth.
11. Spray a rust inhibitor on metallic parts to
minimize corrosion.
12. Allow the engine compartment to air dry
completely before reinstalling the hood.
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4-1
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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.
@
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4-3
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EJU01299
Lubrication
WARNING@ To reduce the risk of fire or explosion:
Never pour or spray gasoline, or any sub-
stance other than a rust inhibitor through
the hole in the carburetor silencer cover.
@
CAUTION:@
Make sure to replace the cap securely
after fogging the engine, otherwise
water could enter the engine and
cause damage.

Do not attempt to run the engine at full
throttle or for more than 15 seconds
while the watercraft is out of the water,
otherwise the engine may overheat
and/or seize.
@
1. Open the silencer cap 1 on the silencer.
2. Start the engine with the watercraft in a
well-ventilated area.
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5-3
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Emergency procedures
EJU01119
Cleaning the jet intake and
impeller
If weeds or debris get caught in the intake
or impeller, cavitation can occur, causing jet
thrust to decrease even though engine
speed rises. If this condition is allowed to
continue, the engine will overheat and may
seize. If there is any sign that the jet intake
or impeller is clogged with weeds or debris,
beach the watercraft and check the intake
and impeller. Always stop the engine before
beaching the watercraft.
WARNING@ Before attempting to remove weeds or
debris from the jet intake or impeller
areas, shut the engine off and remove
the clip from the engine shut-off switch.
Severe injury or death could result from
contact with the rotating parts of the jet
pump.
@
1. Turn the watercraft on its side as shown.
CAUTION:@
Place a suitable clean cloth or carpet-
ing underneath the watercraft to pro-
tect it from abrasions and scratches.

Always turn the watercraft over onto
its port (left) side.

When turning the watercraft on its
side, support the bow so the handle-
bars cannot be bent or damaged.
@
2. Remove any weeds or debris from
around the drive shaft, impeller, pump
housing, and jet thrust nozzle.
If debris is difficult to remove, consult
your Yamaha dealer.
UF1N71.book Page 3 Tuesday, June 4, 2002 3:34 PM