2018 YAMAHA SUPERJET check engine

Maintenance
60
EJU3437AChecking the spark plugs
WARNING
EWJ00351
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, insu-
lator, 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 reinstalling a spark plug, a good estimate
of the correct torque is 1/12 turn past finger-
tight. When you are installing a new spark
plug, a good estimate of the correct torque is
1/2 to 2/3 turn past finger-tight.
(3) Wipe off any water or dirt inside the
spark plug cap.
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 N·m (2.55 kgf·m, 18.4 lb·ft)
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Trouble recovery
64
EJU34562
Troubleshooting
If you have any trouble with your watercraft, use the troubleshooting chart to check for the
possible cause.
If you cannot find the cause, consult a Yamaha dealer.
EJU34576Troubleshooting 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
19
Fuse Burned out Replace fuse and
check wiring67
Battery Run down Recharge 51
Poor terminal con-
nectionsTighten as required
51
Terminal corroded Clean or replace 51
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”21
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 60
Spark plug
capNot connected or
looseConnect properly
60
Crankcase Filled with water Have serviced by
Yamaha dealer69
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer61
Choke Knob moves back on
its ownTighten choke knob
adjusting nut61
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Trouble recovery
66
EJU34625
Emergency proceduresEJU34635Cleaning the jet intake and impeller
WARNING
EWJ00783
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 water-
craft above trolling speed until they have
been removed.
[ECJ00654]
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
watercraft.
(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, sup-
port the bow so that the handlebars
are not bent or damaged.
[ECJ00662]
STOP
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70
Index
2-stroke engine oil ................................... 28
A
After removing the watercraft from the
water ..................................................... 49
B
Battery care.............................................. 51
Battery checks ......................................... 36
Battery, jumping ....................................... 67
Beaching the watercraft ........................... 49
Bilge water check..................................... 36
Bilge water, draining ................................ 29
Bilge water, draining on water ................. 29
Boarding and starting in deep water........ 47
Boarding and starting in shallow water.... 46
Bow rope hole .......................................... 24
C
Capsized watercraft ................................. 48
Carburetor, adjusting ............................... 61
Choke cable, adjusting ............................ 61
Choke knob.............................................. 21
Cleaning ................................................... 54
Cleaning the watercraft ............................ 51
Cooling water pilot outlet ......................... 21
Cooling water pilot outlet check .............. 39
Craft Identification Number (CIN)............... 1
Cruising limitations..................................... 9
E
Emergency procedures ............................ 66
Engine break-in ........................................ 32
Engine compartment check ..................... 35
Engine idling speed, adjusting ................. 62
Engine overheat warning system ............. 22
Engine serial number ................................. 1
Engine shut-off cord (lanyard) check ....... 38
Engine shut-off switch ............................. 19
Engine stop switch................................... 19
Engine unit check..................................... 36
Enjoy your watercraft responsibly............ 15
Equipment ................................................ 23
F
Fire extinguisher check ............................ 39
Fire extinguisher container....................... 25
Fire extinguisher container checks .......... 39
Flushing the cooling water passages....... 50
Fuel .......................................................... 27Fuel and engine oil requirements ............. 27
Fuel cock knob......................................... 21
Fuel filter, checking .................................. 61
Fuel level check........................................ 35
Fuel system checks ................................. 35
Fuel tank, filling ........................................ 28
Fuse, replacing ......................................... 67
G
Getting to know your watercraft .............. 40
Glossary, watercraft ................................. 16
H
Hazard information................................... 13
Hood ........................................................ 23
Hood check .............................................. 39
Hull and deck check ................................ 39
I
Identification numbers ............................... 1
J
Jet intake and impeller, cleaning.............. 66
Jet intake checks ..................................... 39
Jet thrust nozzle angle, adjusting ............ 57
Jumper cables, connecting ...................... 67
L
Labels, important ....................................... 3
Labels, other .............................................. 7
Labels, warning .......................................... 4
Launching the watercraft ......................... 41
Learning to operate your watercraft......... 40
Leaving the watercraft.............................. 43
Limitations on who may operate the
watercraft ................................................ 8
Long-term storage ................................... 54
Lubrication ............................................... 54
Lubrication points .................................... 61
M
Main components, location of ................. 17
Maintenance............................................. 56
Manufactured date label ............................ 2
Mixing fuel and oil .................................... 28
O
Operating in weeded areas ...................... 49
Operating positions .................................. 40
Operating the watercraft .......................... 43
Operating your watercraft ........................ 40
Operation requirements ........................... 10
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Index
71
P
Periodic maintenance chart ..................... 59
Post-launch checks ................................. 39
Post-operation care ................................. 50
Pre-launch checks ................................... 35
Pre-operation check points ..................... 35
Pre-operation checklist ............................ 33
Primary Identification (PRI-ID) number ...... 1
R
Recommended equipment ...................... 12
Rustproofing ............................................ 55
S
Safe boating rules .................................... 14
Safety equipment check .......................... 39
Spark plugs, checking ............................. 60
Start switch .............................................. 19
Starting off ............................................... 45
Starting the engine on water .................... 41
Steering friction, adjusting ....................... 56
Steering pole ............................................ 20
Steering pole check ................................. 37
Steering system ....................................... 20
Steering system checks ........................... 36
Stern rope hole ........................................ 24
Stopping the engine ................................. 43
Stopping the watercraft ........................... 45
Storage pouch ......................................... 24
Storage pouch checks ............................. 38
Submerged watercraft ............................. 69
Switch checks .......................................... 38
T
Throttle lever ............................................ 20
Throttle lever checks ................................ 37
Tool kit ..................................................... 56
Towing the watercraft .............................. 68
Transporting ............................................. 30
Troubleshooting ....................................... 64
Troubleshooting chart .............................. 64
Turning the watercraft .............................. 43
W
Water separator ....................................... 22
Water separator check............................. 36
Watercraft characteristics ........................ 13
Watercraft control functions .................... 19
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