SERVICE ADJUSTMENT PROCEDURES
SPARK PLUG INSPECTION AND TEST
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Remove the spark plugs from the engine.
Visually check the spark plugs for the following and
replace if defective.
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Broken insulator.
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Worn electrode.
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Deposited carbon. Use a plug cleaner for cleaning.
Clean porcelain insulator above shell as well.
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Damaged or broken gasket.
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Burnt condition of porcelain insulator at spark gap.
If black carbon deposit is evident, probable cause is
too rich a fuel mixture or extremely low air intake.
Misfiring due to excessive spark gap is also suspected.
If insulator is burnt white, too lean a fuel mixture,
excessively advanced ignition timing, improperly
tightened plug, etc. are suspected.
Connect the spark plug to the high tension cable, ground
outer electrode (main body), and crank engine. In the
atmosphere, only short sparks are produced because of
small discharge gap. If the spark plug is good, however,
sparks will occur in discharge gap (between electrodes).
In a defective spark plug, no sparks will occur because
of leak of insulation puncture.
Check plug gap with plug gap gauge. If it is .not within
specified limit, adjust by bending ground electrode.
Make sure that the gap of even a new spark plug is
checked before spark plug is mounted to engine.
Spark plug gap . . . .’ . . . .
1.0-1.1 mm (.039-.0’43 in.)
Install the spark plug and tighten to specified torque.
If it is overtorqued, damage to threaded ,portion of
cylinder head might result.
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Spark plug . . . . . . . . . . . . . 20-29 Nm (15-21 ft.lbs.)
Spark Test Without Cranking
If spark test is performed by cranking while the catalyst is
hot, unburned gas will be supplied to the catalyst, and this is
not desirable to the catalyst.
For this reason, use the following methods which;allow spark
test to be performed without cranking.
Spark plug
Defective insulation
Defective insuktion
1 E LO3,
I”-\.
lllllllllllllllillllllllllll
Gap
lELO2
High tension cable
5-10 mm
(.2-.4 in.)
lEL03
8-78
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