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MAINTENANCE
MAINTENANCE, REPLACEMENT OR REPAIR OF
THE EMISSION CONTROL DEVICES AND SYSTEM
MAY BE PERFORMED BY ANY NON-ROAD ENGINE
REPAIR ESTABLISHMENT OR INDIVIDUAL.
Carburetor adjustment (Fig. 31)
T
H
L
Fig. 31
In the carburetor, fuel is mixed with air. When the
engine is test run at the factory, the carburetor is
adjusted. A further adjustment may be required,
according to climate and altitude. The carburetor
has one adjustment possibility:
T = Idle speed adjustment screw.
Idle speed adjustment (T)
Check that the air fi lter is clean. When the idle speed
is correct, the cutting attachment will not rotate. If
adjustment is required, close (clockwise) the T-screw,
with the engine running, until the cutting attachment
starts to rotate. Open (counter-clockwise) the screw
until the cutting attachment stops. You have reached
the correct idle speed when the engine runs smoothly
in all positions well below the rpm when the cutting
attachment starts to rotate.
If the cutting attachment still rotates after idle speed
adjustment, contact Hitachi Authorized Service
Centers.
WARNING
When the engine is idling the cutting attachment
must under no circumstances rotate.
NOTE
Do not touch the High speed adjustment (H) and
the Low speed adjustment (L).
Those are only for Hitachi Authorized Service
Centers.
If you rotate them, it will cause a serious damage
to the machine.
Air fi lter (Fig. 32)
The air fi lter (40) must be cleaned from dust and dirt
in order to avoid:
○
Carburetor malfunctions.
○
Starting problems.
○
Engine power reduction.
○
Unnecessary wear on the engine parts.
○
Abnormal fuel consumption.
Clean the air fi lter daily or more often if working in
exceptionally dusty areas.
Remove the air fi lter cover (41) and the fi lter (40).
Rinse them in warm soap suds. Check that the fi lter
is dry before reassembly. An air fi lter that has been
used for some time cannot be cleaned completely.
Therefore, it must regularly be replaced with a new
one. A damaged fi lter must always be replaced.
40
41
Fig. 32
Spark plug (Fig. 33)
The spark plug condition is infl uenced by:
○
An incorrect carburetor setting.
○
Wrong fuel mixture (too much oil in the gasoline)
○
A dirty air fi lter.
○
Hard running conditions (such as cold weather).
These factors cause deposits on the spark plug
electrodes, which may result in malfunction and
starting diffi culties. If the engine is low on power,
diffi cult to start or runs poorly at idling speed, always
check the spark plug fi rst. If th e s pa rk plug is dir ty, clea n
it and check the electrode gap. Readjust if necessary.
The correct gap is 0.024” (0.6 mm). The spark plug
should be replaced after about 100 operation hours or
earlier if the electrodes are badly eroded.
0.6 mm
0.024"(0.6 mm)
Fig. 33
NOTE
In some areas, local law requires using a resistor
spark plug to suppress ignition signals. If this
machine was originally equipped with resistor
spark plug, use same type of spark plug for
replacement.