air YAMAHA SUPERJET 2003 User Guide

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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)
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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
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Towing the watercraft
If the watercraft becomes inoperative in
the water, it can be towed to shore.
If the watercraft must be towed in an
emergency using a tow line, the operator
should ride the watercraft, holding onto the
handlebars and supporting his body weight
on the riding tray. This will help keep the bow
of the watercraft out of the water.
CAUTION:@
Tow the watercraft at 5 mph (8 km/h) or
less, otherwise water could enter the
engine through the exhaust passages
or through the air intake and flood the
engine compartment if it is towed too
fast.

Tow the watercraft using the rope
hole1 only.

The bow must be kept up out of the
water during towing to prevent water
from entering the engine compart-
ment.
@
WARNING@
The watercraft should only be towed in
an emergency.

The towline should be long enough so
that the watercraft will not collide with
the towing boat when slowing down. A
good rule of thumb is a towline that is
three times the combined length of the
towing boat and the watercraft.

The operator of the towing boat must
keep speed to a minimum and avoid
traffic or obstacles which could be a
hazard to the operator on the water-
craft.
@
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