Husqvarna 1151375-95 Maintenance, Carburetor, Function, Basic settings, Fine adjustment, H L T

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, Basic settings, Fine adjustment

WARNING! Do not start the chain saw

! unless the bar, chain and clutch cover (chain brake) are fitted, otherwise the clutch may come loose and cause personal injury.

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

H L

T

•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 settings and running in

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.

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Rec. idle speed: 2800 rpm

Fine adjustment

When the machine has been ”run-in” the carburetor should be finely adjusted. The fine adjustment should be carried out by a qualified person. First adjust the L- jet, then the idling screw T and then the H-jet.

Fine tuning may be required if the chain saw, after changing the type of fuel, performs differently with regard to starting, acceleration, maximum speed, etc.

Conditions

•Before any adjustments are made the air filter should be clean and the cylinder cover fitted. Adjusting the carburetor while a dirty air filter is in use will result in a leaner mixture next time the filter is cleaned. This can give rise to serious engine damage.

•Carefully turn both jets, L and H, so that they are midway between fully screwed in and fully screwed out.

•Do not attempt to adjust the L and H jets beyond either stop as this could cause damage.

•Now start the machine according to the starting instructions and let it warm up for 10 minutes. CAUTION! If the chain rotates while idling the T- screw must be turned anti-clockwise until the chain stops.

•Place the machine on a flat surface so that the bar points away from you and so that the bar and chain do not come into contact with the surface or other objects.

Low speed jet L

Turn the low speed jet L clockwise until it stops. If the engine accelerates poorly or idles unevenly, turn the low speed jet L anticlockwise until good acceleration and idling are achieved.

CAUTION! If the chain rotates while idling the T-screw must be turned anti-clockwise until the chain stops.

Fine adjustment of the idling speed T

Final setting of the idling speed T

Adjust the idle speed with the T-screw. If it is necessary to re-adjust, turn the T-screw clockwise while the engine is running, until the chain starts to rotate. Then turn counter- clockwise until the chain stops. A correctly adjusted idle speed setting occurs when the engine runs smoothly in every position. It should also be good margin to the rpm when the chain starts to rotate.

WARNING! Contact your servicing

! dealer, if the idle speed setting cannot be adjusted so that the chain stops at idle. Do not use the chain saw until it has been properly adjusted or repaired.

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