MAINTENANCE

Carburettor adjustment

The carburettor can be designed in different ways, depending on existing environmental and emissions legislation. Some chain saws are equipped with movement limiters on the carburettor’s adjuster screws. These limit the adjustment possibilities to a maximum of a 1/2 turn.

H

L

1/2

1/2

When your chain saw is equipped with a carburettor that features movement limiters, the carburettor should be adjusted according to the instructions under the heading Carburettor with movement limiters.

When your chain saw is equipped with a carburettor that does not feature movement limiters, the carburettor should be adjusted according to the instructions under the heading Carburettor without movement limiters.

H

L

Contact your servicing dealer (retailer) if you are uncertain of which type of carburettor your chain saw is equipped with.

Carburettor with movement limiters

H

L

1/2

1/2

Your Husqvarna product has been designed and manufactured to specifications that reduce harmful emissions.

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

Adjusting the carburettor means that the engine is adapted to local operating conditions, e.g. climate, altitude, petrol and the type of 2-stroke oil.

The carburettor has three adjustment controls:

-L = Low speed jet

-H = High speed jet

-T = Idle adjustment screw

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 carburettor settings are adjusted during testing at the factory. Avoid running at a too high speed during the first 10 hours.

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

English 29

Page 29
Image 29
Husqvarna 1153177-26 manual Maintenance, Carburettor adjustment, Carburettor with movement limiters