2018 YAMAHA SUPERJET spark plugs

Table of contents
Capsized watercraft ......................... 48
Beaching the watercraft ................... 49
Operating in weeded areas .............. 49
After removing the watercraft from
the water ....................................... 49
Care and storage............................. 50
Post-operation care ...................... 50
Flushing the cooling water
passages....................................... 50
Cleaning the watercraft .................... 51
Battery care ...................................... 51
Long-term storage ........................ 54
Cleaning ........................................... 54
Lubrication ....................................... 54
Rustproofing..................................... 55
Maintenance .................................... 56
Maintenance.................................. 56
Tool kit.............................................. 56
Adjusting the steering friction .......... 56
Adjusting the jet thrust nozzle
angle ............................................. 57
Periodic maintenance chart ............. 59
Checking the spark plugs ................ 60
Lubrication points ............................ 61
Checking the fuel filter ..................... 61
Adjusting the choke cable................ 61
Adjusting the carburetor................... 61
Specifications .................................. 63
Specifications................................ 63
Trouble recovery ............................. 64
Troubleshooting ............................ 64
Troubleshooting chart ...................... 64
Emergency procedures ................. 66
Cleaning the jet intake and
impeller ......................................... 66
Jumping the battery ......................... 67
Replacing the fuse ........................... 67
Towing the watercraft ...................... 68
Submerged watercraft ..................... 69
Index................................................. 70
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Maintenance
59
EJU40831Periodic maintenance chart
The periodic maintenance chart gives general guidelines for periodic maintenance. Have a
Yamaha dealer perform the checks in the following chart. However, maintenance may need
to be performed more frequently depending on your operating conditions. If you have any
questions, consult a Yamaha dealer.
This “ ” mark indicates maintenance that you may do yourself.
This “ ” mark indicates items to be checked and serviced by a Yamaha dealer.
Item OperationInitial Thereafter every
Page 10
hours50 hours100
hours200
hours
6
months12
months12
months24
months
Spark plugsCheck, clean, replace 60
Lubrication pointsLubricate 54
Intermediate
housingLubricate 61
Fuel systemCheck —
Fuel filterCheck 61
Check, replace —
Fuel tankCheck, clean —
CarburetorCheck, adjust —
Engine idling
speedCheck, adjust 62
Carburetor throttle
shaftCheck —
Bilge strainerClean —
ImpellerCheck —
Jet thrust nozzle
angleCheck, adjust —
Handlebar pivot
shaftCheck, adjust —
Steering frictionCheck, adjust —
Steering masterCheck, adjust —
Throttle cableCheck, adjust —
Choke cableCheck, adjust 61
BatteryCheck, charge —
Rubber couplingCheck —
Engine mountCheck —
Nuts and boltsCheck —
UF4D74E0.book Page 59 Tuesday, March 21, 2017 9:35 AM

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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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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