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 filter 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 filter (Fig. 31)

The air filter 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 filter daily or more often if working in exceptionally dusty areas.

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Fig. 31

Cleaning the air filter

Open the air filter cover and the filter (28). Rinse it in warm soap suds. Check that the filter is dry before reassembly. An air filter that has been used for some time cannot be cleaned completely. Therefore, it must regularly be replaced with a new one. A damaged filter must always be replaced.

Fuel filter (Fig. 32)

Drain all fuel from fuel tank and pull fuel filter line from tank. Pull filter 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 influenced by: ○ An incorrect carburetor setting

○ Wrong fuel mixture (too much oil in the gasoline) ○ A dirty air filter

○ Hard running conditions (such as cold weather)

These factors cause deposits on the spark plug electrodes, which may result in malfunction and starting difficulties. If the engine is low on power, difficult to start or runs poorly at idling speed, always check the spark plug first. 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.

0.6mm

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 flexible shaft, first 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).

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