Husqvarna 356BTX manual Maintenance, Carburetor, Muffler

MAINTENANCE

Carburetor

Your Husqvarna product has been designed and manufactured to specifications that reduce harmful emissions. After the engine has used 8-10 tanks of fuel the engine will be run-in. To ensure that it continues to run at peak performance and to minimise harmful exhaust emissions after the running-in period, ask your dealer/ service workshop (who will have a rev counter at their disposal) to adjust your carburettor.

Function

The carburetor governs the engine’s speed via the throttle control. Air and fuel are mixed in the carburetor. The air/ fuel mixture is adjustable. Correct adjustment is essential to get the best performance from the machine.

The setting of the carburetor means that the engine is adapted to local conditions, for example, the climate, altitude, fuel and the type of 2-stroke oil.

The carburetor has three adjustment controls:

•L = Low speed jet

•H = High speed jet

•T = Idle adjustment screw

L T

H

The L and H-jets are used to adjust the supply of fuel to match the rate that air is admitted, which is controlled with the throttle. If they are screwed clockwise the air/fuel ratio becomes leaner (less fuel) and if they are turned anti- clockwise the ratio becomes richer (more fuel). A lean mixture gives a higher engine speed and a rich mixture gives a lower engine speed.

The T-screw regulates the throttle setting at idle speed. If the T-screw is turned clockwise this gives a higher idle speed; turning it anti-clockwise gives a lower idle speed.

Basic setting

The basic carburetor settings are adjusted during testing at the factory. The basic setting is richer than the optimal setting and should be maintained for the first few hours the machine is in use. The carburettor should then be finely adjusted. Fine adjustment should be carried out by a skilled technician.

Adjustment of the idle speed

Before any adjustments are made, make sure that the air filter is clean and the air filter cover is fitted.

Adjust the idle speed screew T clockwise respectively anti-clockwise until an idle speed of 2300 rpm is reached.

Muffler

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.

The muffler is equipped with a special spark arrestor screen. The spark arrestor screen should be cleaned once a month. This is best done with a wire brush.

To remove the spark arrestor screen proceed as follows:

Remove the screws to the capillary tube and exhaust pipe.

English – 17