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SPARK PLUGS
Electrical Shock can cause injury.
Do not touch wires while engine is running.
Spark Plug Component and Details
A
B
C
A
Wire Gauge
C
Ground Electrode
NOTE: Do not clean spark plug in a machine using
abrasive grit. Some grit could remain in spark
plug and enter engine causing extensive wear
and damage.
Engine misfi re or starting problems are often caused
by a spark plug that has improper gap or is in poor
condition.
Engine is equipped with following spark plugs:
Gap
0.76 mm (0.030 in.)
Thread Size
14 mm
Reach
19.1 mm (3/4 in.)
Hex Size
15.9 mm (5/8 in.)
Refer to Maintenance for Repairs/Service Parts.
Service
Clean out spark plug recess. Remove plug and replace.
1. Check gap using wire feeler gauge. Adjust gap to
0.76 mm (0.030 in.).
2. Install plug into cylinder head.
3. Torque plug to 27 N·m (20 ft. lb.).
62 690 13 Rev. A
CAUTION
D
B
Spark Plug
D
Gap
KohlerEngines.com
Inspection
Inspect each spark plug as it is removed from cylinder
head. Deposits on tip are an indication of general
condition of piston rings, valves, and throttle body.
Normal and fouled plugs are shown in following photos:
Normal
Plug taken from an engine operating under normal
conditions will have light tan or gray colored deposits. If
center electrode is not worn, plug can be set to proper
gap and reused.
Worn
On a worn plug, center electrode will be rounded and
gap will be greater than specifi ed gap. Replace a worn
spark plug immediately.
Wet Fouled
A wet plug is caused by excess fuel or oil in combustion
chamber. Excess fuel could be caused by a restricted
air cleaner, a throttle body problem, or operating engine
with too much choke. Oil in combustion chamber is
usually caused by a restricted air cleaner, a breather
problem, worn piston rings, or valve guides.
Electrical System
57
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