2001 YAMAHA SUPERJET engine

4-7
E
EJU00535a
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 genuine
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.
@
E_GM6-4.fm Page 7 Tuesday, July 11, 2000 11:28 AM

4-13
E
EJU00948
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:
NGK BR-7HS
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Spark plug torque:
25 Nm (2.5 m·kg, 18 ft·lb)
E_GM6-4.fm Page 13 Tuesday, July 11, 2000 11:28 AM

4-19
E
EJU00573
Adjusting the carburetor
The carburetor is a vital part of the engine
and requires very sophisticated adjustment.
Most adjusting should be left to a Yamaha
dealer who has the professional knowledge
and experience to perform it. However, the
operator may adjust the trolling speed as
part of the usual maintenance routine.
CAUTION:@The carburetor was set at the Yamaha
factory after many tests. If the settings
are disturbed by someone who does not
have the necessary technical knowledge,
poor engine performance and damage
may result.
@
EJU00574a
Adjusting the trolling speed
1. Put the watercraft in the water.
2. Start the engine and warm it up for 1 or
2 minutes. Using a diagnostic tachome-
ter, adjust the engine speed to specifica-
tion.
3. Turn the throttle stop screw 1 clockwise
to increase engine speed if necessary.
Turn it counterclockwise to decrease
engine speed if necessary.
Trolling speed: 1,250–1,350 r/min
E_GM6-4.fm Page 19 Tuesday, July 11, 2000 11:28 AM

4-23
E
EJU00590
Specifications
*1: Pump Octane Number
*1: Research Octane NumberMODEL
ITEMUnit SJ700
WATERCRAFT CAPACITY
Maximum people on board Number of people 1
DIMENSIONS
Length mm (in) 2,240 (88.2)
Width mm (in) 680 (26.8)
Height mm (in) 660 (26.0)
Dry weight kg (lb) 132 (291)
PERFORMANCE
Maximum power output kW (PS) @ r/min 53.6 (73) @ 6,300
Maximum fuel consumption L/h (US gal/h, Imp gal/h) 29 (7.7, 6.4)
Cruising range at full throttle hr. 0.6
Trolling speed r/min 1,250–1,350
ENGINE
Engine type 2-stroke
Number of cylinders 2
Engine displacement
cm
3 (cu in)701 (42.78)
Bore & stroke mm (in) 81 ×
68 (3.19 ×
2.68)
Compression ratio 7.2
Lubrication system Pre-mixed fuel
Cooling system Water cooled
Starting system Electric starter
Ignition system CDI
Spark plug BR-7HS (NGK)
Spark plug gap mm (in) 0.6–0.7 (0.024–0.028)
Battery capacity V-AH 12-19
Charging system Flywheel magneto
DRIVE UNIT
Propulsion system Jet pump
Jet pump type Mixed flow, single stage
Impeller rotation Counterclockwise (viewed from rear)
Transmission Direct drive from engine
Jet thrust nozzle angle Degree 37, 41, 45, 49
FUEL AND OIL
Recommended fuel Regular unleaded gasoline
Minimum octane rating PON (*1)
RON (*1)86
90
Recommended engine oil YAMALUBE 2-W, or an equivalent NMMA-
certified TC-W3 marine oil
Fuel mixing ratio (fuel to oil) 50:1
Fuel tank capacity
Total L (US gal, Imp gal) 18 (4.8, 4.0)
Reserve L (US gal, Imp gal) 5.5 (1.45, 1.21)
E_GM6-4.fm Page 23 Tuesday, July 11, 2000 11:28 AM

5-1
E
EJU00595
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.
EJU00596
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 4-18
Poor terminal connec-
tionsTighten as required
4-18
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
E_GM6-5.fm Page 1 Tuesday, July 11, 2000 11:29 AM

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
E_GM6-5.fm Page 2 Tuesday, July 11, 2000 11:29 AM

5-3
E
EJU00597
Emergency procedures
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
coming in 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 and secure the
steering pole, otherwise the steering
pole and handlebars could be bent or
damaged.
@
2. Remove any weeds or debris from
around the drive shaft, impeller, and jet
thrust nozzle.
If debris is difficult to remove, consult
your Yamaha dealer.
E_GM6-5.fm Page 3 Tuesday, July 11, 2000 11:29 AM

5-4
E
CAUTION:@Always avoid operating your watercraft in
areas where weed growth is thick. If trav-
eling in weeded areas is unavoidable,
operate the engine alternately at partial
throttle and full throttle. Weeds tend to
accumulate more at a steady speed and
at trolling speed. If weeds clog the intake
or impeller area and cause cavitation, fol-
low the cleaning procedure above.
@
EJU00599
Jumping the battery
If the watercraft battery has run down, the
engine can be started using a 12-volt bat-
tery and jumper cables.
WARNING@Battery electrolyte is poisonous and dan-
gerous, causing severe burns, etc. Elec-
trolyte contains sulfuric acid. Avoid
contact with skin, eyes or clothing.
Antidotes
External: Flush with water.
Internal: Drink large quantities of water
or milk. Follow with milk of magnesia,
beaten egg, or vegetable oil. Call physi-
cian immediately.
Eyes: Flush with water for 15 minutes
and get prompt medical attention
Batteries give off explosive gases. Keep
sparks, flame, cigarettes, etc. well away.
If using or charging the battery in an
enclosed area, make sure that it is well
ventilated. Always shield your eyes when
working near batteries.
KEEP OUT OF THE REACH OF CHIL-
DREN
@
E_GM6-5.fm Page 4 Tuesday, July 11, 2000 11:29 AM