2012 YAMAHA SUPERJET engine

Maintenance
59
EJU34378Checking the spark plugs
WARNING
EWJ00350
Be careful not to damage the insulator
when removing or installing a spark plug.
A damaged insulator could allow sparks to
escape, which could result in a fire or ex-
plosion.
Remove and check the condition of the spark
plugs.
The condition of a spark plug can indicate
something about the condition of the engine.
For example, if the center electrode portion 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.
To remove a spark plug:
(1) Remove the hood. (See page 23 for hood
removal and installation procedures.)
(2) Remove the spark plug cap.
(3) Remove the spark plug, and then check
the condition of the spark plug and the
spark plug gap. If the electrode portion is
significantly discolored, if electrode ero-
sion becomes excessive, if carbon and
other deposits are excessive, or if the
spark plug gap is not within the specified
range, replace the spark plug.
TIP:
When the engine is operating normally, the
color of the spark plug electrode portion will
be a medium-to-light tan.
To install a spark plug:
(1) Wipe off any dirt from the threads, insula-
tor, and gasket surface of the spark plug.
(2) Install the spark plug, and then tighten it
to the specified torque.
TIP:
If a torque wrench is not available when you
are installing a spark plug, a good estimate of
Nuts and boltsCheck— Item OperationInitial Thereafter every
Page 10
hours50 hours100
hours200
hours
6
months12
months12
months24
months
1Insulator
2Electrode
3Spark plug gap
Specified spark plug:
BR7HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Tightening torque:
Spark plug:
25.0 Nm (2.55 kgf-m, 18.4 ft-lb)
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Maintenance
61
EJU34463Adjusting the carburetor
NOTICE
ECJ00172
If the carburetor settings are disturbed by
someone who does not have the neces-
sary technical knowledge, poor engine
performance and damage may result.
The carburetor is a vital part of the engine and
requires very sophisticated adjustments.
Most adjustments should be left to a Yamaha
dealer who has the professional knowledge
and experience to make them.
However, the operator may adjust the engine
idling speed as part of the usual maintenance
routine.
EJU34471Adjusting the engine idling speed
(1) Place the watercraft in the water.
(2) Start the engine and warm it up for 1 to 2
minutes.
(3) While using a diagnostic tachometer, turn
the throttle stop screw to adjust the en-
gine idling speed to specification. Turn
the throttle stop screw clockwise to in-
crease the engine idling speed or coun-
terclockwise to decrease the engine
idling speed.
1Throttle stop screw
Engine idling speed:
1300 ±50 r/min
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Specifications
62
EJU34542
Specifications
Watercraft capacity:
Maximum people on board:
1 person
Dimensions:
Length:
2240 mm (88.2 in)
Width:
680 mm (26.8 in)
Height:
660 mm (26.0 in)
Dry weight:
139 kg (306 lb)
Performance:
Maximum output (according to ISO 8665/SAE
J1228):
48.5 kW@6250 r/min
Maximum fuel consumption:
29.0 L/h (7.7 US gal/h, 6.4 Imp.gal/h)
Cruising range at full throttle:
0.62 hour
Trolling speed:
1300 ±50 r/min
Engine:
Engine type:
2-stroke
Number of cylinders:
2
Engine displacement:
701 cm³
Bore & stroke:
81.0 × 68.0 mm (3.19 × 2.68 in)
Compression ratio:
7.2 : 1
Lubrication system:
Pre-mixed fuel and oil
Cooling system:
Water
Starting system:
Electric
Ignition system:
C.D.I.
Spark plug:
BR7HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Battery capacity:
12 V, 19 AhCharging system:
Flywheel magneto
Drive unit:
Propulsion system:
Jet pump
Jet pump type:
Axial flow, single stage
Impeller rotation:
Counterclockwise
Jet thrust nozzle angle:
P1: 14.4+14.4°
P2: 17.3+17.3°
Fuel and oil:
Recommended fuel:
Regular unleaded gasoline
Minimum octane rating (PON):
86
Minimum octane rating (RON):
90
Recommended engine oil:
YAMALUBE 2-W or TC-W3 outboard motor
oil or equivalent
Fuel mixing ratio (fuel to oil):
50 :1
Fuel tank total capacity:
18 L (4.8 US gal, 4.0 Imp.gal)
Fuel tank reserve capacity:
5.5 L (1.5 US gal, 1.2 Imp.gal)
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Trouble recovery
63
EJU34561
Troubleshooting
If you have any trouble with your watercraft, use the troubleshooting chart to check for the pos-
sible cause.
If you cannot find the cause, consult a Yamaha dealer.
EJU34575Troubleshooting chart
TROUBLE POSSIBLE CAUSE REMEDY PAGE
Engine does not
start (Starter motor
does not turn over)Engine shut-
off switchClip not in place Install clip
18
Fuse Burned out Replace fuse and
check wiring66
Battery Run down Recharge 50
Poor terminal con-
nectionsTighten as required
50
Terminal corroded Clean or replace 50
Starter motor Faulty Have serviced by
Yamaha dealer—
Engine does not
start (Starter motor
turns over)Fuel cock Turned to “OFF”Turn fuel cock knob to
“ON”20
Fuel Empty Refill as soon as pos-
sible28
Stale or contaminat-
edHave serviced by
Yamaha dealer—
Fuel tank Water or dirt present Have serviced by
Yamaha dealer—
Spark plug Fouled or defective Replace 59
Spark plug
capNot connected or
looseConnect properly
59
Crankcase Filled with water Have serviced by
Yamaha dealer67
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer60
Choke Knob moves back on
its ownTighten choke knob
adjusting nut60
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Trouble recovery
64
Engine runs irregu-
larly or stallsFuel Empty Refill as soon as pos-
sible28
Stale or contaminat-
edHave serviced by
Yamaha dealer—
Too much oil in fuel
mixing ratioCorrect fuel-to-oil ra-
tio to 50:127
Choke Knob is left pulled Push fully in 20
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer60
Fuel tank Water or dirt present Have serviced by
Yamaha dealer—
Spark plug Fouled or defective Replace 59
Incorrect heat range Replace 59
Gap incorrect Replace 59
Spark plug
capNot connected or
looseConnect properly
59
Cracked, torn or dam-
agedHave serviced by
Yamaha dealer—
Electrical wir-
ingLoose electrical con-
nectionsHave serviced by
Yamaha dealer—
Carburetor Incorrect idle adjust-
mentHave serviced by
Yamaha dealer—
Clogged Have serviced by
Yamaha dealer61
Watercraft slow or
loses powerCavitation Jet intake clogged Clean 65
Impeller damaged or
wornHave serviced by
Yamaha dealer65
Engine over-
heatedJet intake clogged Clean
65
Fuel filter Clogged Have serviced by
Yamaha dealer60
Spark plug Fouled or defective Replace 59
Incorrect heat range Replace 59
Gap incorrect Replace 59
Spark plug
capsNot connected or
looseConnect properly
59
Fuel Stale or contaminat-
edHave serviced by
Yamaha dealer— TROUBLE POSSIBLE CAUSE REMEDY PAGE
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Trouble recovery
65
EJU34623
Emergency procedures EJU34634Cleaning the jet intake and impeller
WARNING
EWJ00782
Before attempting to remove weeds or de-
bris from the jet intake or impeller area,
shut the engine off and remove the clip
from the engine shut-off switch. Severe in-
jury or death could result from coming in
contact with the rotating parts of the jet
pump.
If weeds or debris gets caught in the jet 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.
NOTICE: If weeds or debris gets caught in
the jet intake, do not operate the watercraft
above trolling speed until they have been
removed.
[ECJ00653]
If there is any sign that the jet intake or impel-
ler is clogged with weeds or debris, return to
shore and check the intake and impeller. Al-ways stop the engine before beaching the wa-
tercraft.
(1) Place a suitable clean cloth or carpeting
underneath the watercraft to protect it
from abrasions and scratches. Turn the
watercraft on its side as shown. NOTICE:
Always turn the watercraft over onto
its port (left) side. When turning the
watercraft on its side, support the bow
so that the handlebars are not bent or
damaged.
[ECJ00661]
STOP
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Trouble recovery
66
(2) Remove any weeds or debris from
around the jet intake, drive shaft, impel-
ler, jet pump housing, and jet thrust noz-
zle.
If debris is difficult to remove, consult a
Yamaha dealer.
EJU34641Jumping the battery
If the watercraft battery has run down, the en-
gine can be started using a 12-volt booster
battery and jumper cables.
EJU34653Connecting the jumper cables
WARNING
EWJ01250
To avoid battery explosion and serious
damage to the electrical system:

Do not reverse the polarity of the jumper
cables when connecting to the batteries.

Do not connect the negative (–) jumper
cable to the negative (–) terminal of the
watercraft battery.

Do not touch the positive (+) jumper ca-
ble to the negative (–) jumper cable.
(1) Connect the positive (+) jumper cable to
the positive (+) battery terminals of both
batteries.
(2) Connect one end of the negative (–)
jumper cable to the negative (–) battery
terminal of the booster battery.(3) Connect the other end of the negative (–)
jumper cable to an unpainted bolt on the
cylinder head.
(4) Start the engine, and then disconnect the
jumper cables by reversing the steps
above. (See page 18 for information on
starting the engine.)
EJU34675Replacing the fuse
If the fuse is blown, replace it with the proper
fuse.
To replace the fuse:
(1) Remove the hood. (See page 23 for hood
removal and installation procedures.)
(2) Loosen the cap and remove it.
(3) Pull out the red lead to pull out the fuse
holder from the electrical box.
1Positive (+) jumper cable
2Booster battery
3Negative (–) jumper cable
1Good fuse
2Blown fuse
2 1
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Trouble recovery
67
(4) Open the fuse holder and replace the
fuse with one of the correct amperage.
WARNING! Do not use fuses of a dif-
ferent amperage than recommended.
Substitution with a fuse that has an
improper rating can cause extensive
electrical system damage and possi-
ble fire.
[EWJ00802]
(5) Insert the fuse holder into the electrical
box.
(6) Securely install the cap by tightening it
until it stops.
(7) Securely install the hood in its original po-
sition.
EJU34704Towing the watercraft
WARNING
EWJ00811

The operator of the towing boat must
keep speed to a minimum and avoid traf-
fic or obstacles which could be a hazard
to the operator on the watercraft.

The towline should be long enough so
that the watercraft will not collide with
the towing boat when slowing down.
If the watercraft becomes inoperative in the
water, it can be towed to shore.
To tow the watercraft:
Use a towline that is three times the combined
length of the towing boat and the watercraft.
(1) Securely attach the towline to the bow
rope hole of the watercraft being towed.
(2) Ride the watercraft with your body weight
supported on the riding tray. Hold on to
the handlebars in order to balance the
watercraft and keep the bow up out of the
water. NOTICE: The bow must be kept
up out of the water during towing, oth-
erwise water could flood the engine
compartment or water could flow back
into the engine, causing severe en-
gine damage.
[ECJ01330]
Tow the watercraft at 8 km/h (5 mph) or less.
NOTICE: Tow the watercraft at 8 km/h (5
mph) or less, otherwise water could flood
the engine compartment or water could
flow back into the engine, causing severe
engine damage.
[ECJ01321]
EJU34734
Submerged watercraft
If the watercraft is submerged or flooded with
water, drain the bilge water from the engine
1Fuse holder
2Electrical box
3Fuse
4Cap
Fuse amperage:
Battery fuse:
10 A
1Bow rope hole
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