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Carburetor adjustment (Fig. 30)
Fig. 30
WARNING
○ The cutting attachment may be spinning during carburetor
adjustments.
○ Never start the engine without the complete clutch cover and
tube assembled! Otherwise the clutch can come loose and
cause personal injuries.
In the carburetor, fuel is mixed with air. When the engine is test
run at the factory, the carburetor is basically 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 your Hitachi dealer.
NOTE
○ Standard Idle rpm is 2800-3200 rpm.
WARNING
When the engine is idling the cutting attachment must under no
circumstances rotate.
Air fi lter (Fig. 31)
The air fi lter 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.
28
Fig. 31
Cleaning the air fi lter
Open the air fi lter cover and the fi lter (28). Rinse it 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.
Fuel fi lter (Fig. 32)
Drain all fuel from fuel tank and pull fuel fi lter line from tank. Pull
fi lter element out of holder assembly and rinse element in warm
water with detergent.
Rinse thoroughly until all traces of detergent are eliminated.
Squeeze, do not wring, away excess water and allow element to air
dry.
Fig. 32
NOTE
If element is hard due to excessive dirt buildup, replace it.
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 the spark plug is dirty, clean it
and check the electrode gap. Re-adjust if necessary. The correct
gap is 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
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.
Flexible drive shaft (Fig. 34)
Flexible drive shaft should be removed and lubricated with good
quality lithium grease every 20 hours. To remove the fl exible shaft,
fi rst remove screw (29), loosen bolt (30) and remove the gear case
then pull the shaft out of the drive shaft pipe. Clean the shaft off and
apply a generous coat of lithium grease to it and insert if back into
the drive shaft pipe, turn it unit it drops into place then install the
gear case, install & tighten screw (29) and screw (30).