MAINTENANCE
smoothly. (Burbling has stopped completely). Now screw the
H 
CAUTION! For optimum adjustment of the carburettor, contact a qualified dealer/service workshop that has a revolution counter at their disposal.
Correctly adjusted carburetor
When the carburetor is correctly adjusted the machine will accelerate without hesitation and burble a little at maximum speed. It is also important that the cutting attachment does not rotate at idle. If the low speed jet L is set too lean it may cause starting difficulties and poor acceleration. If the high speed jet H is set too lean it will result in less power, less performance, poor acceleration and/or damage to the engine. If both the L and H jets are set too rich it will results in acceleration problems or too low a working speed.
Adjusting the start throttle speed (343FR, 343FRM, 343R, 345RX)
The correct start throttle speed is set by means of an adjuster on the rear of the handle next to the cable. Use this screw (5 mm Allen screw) to increase or decrease the start throttle speed.
5 mm
Proceed as follows:
1Run the machine at idle.
2Press the start throttle lock as described under the heading Starting and stopping.
3If the start throttle speed is too low (below 4000 rpm), turn the adjuster screw A clockwise until the cutting attachment starts to rotate. Then turn A clockwise a further 1/2 turn.
4If the start throttle speed is too high, turn the adjuster screw A anticlockwise until the cutting attachment stops. Then turn adjuster screw A clockwise a further 1/2 turn.
32 – English
Muffler
CAUTION! Some mufflers are fitted with a catalytic converter. See chapter on Technical data to see whether your machine is fitted with a catalytic converter.
The muffler is designed to reduce the noise level and to direct the exhaust gases away from the operator. The exhaust gases are hot and can contain sparks, which may cause fire if directed against dry and combustible material.
Some mufflers are equipped with a special spark arrestor screen. If your machine has this type of muffler, you should clean the screen at least once a week. This is best done with a wire brush.
On mufflers without a catalytic converter the screen should be cleaned weekly, or replaced if necessary. On mufflers fitted with a catalytic converter the screen should be checked, and if necessary cleaned, monthly. If the
screen is damaged it should be replaced.
If the screen is frequently blocked, this can be a sign that the performance of the catalytic converter is impaired. Contact your dealer to inspect the muffler. A blocked screen will cause the machine to overheat and result in damage to the cylinder and piston.
CAUTION! Never use a machine with a defective muffler.
WARNING! Mufflers fitted with catalytic
! converters get very hot during use and remain so for some time after stopping. This also applies at idle speed. Contact can result in burns to the skin.
Remember the risk of fire!
Cooling system
To keep the working temperature as low as possible the machine is equipped with a cooling system.