Husqvarna 235F, Operator'S Manual

MAINTENANCE

English

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 27

Carburettor

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 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 setting

•

The basic carburettor 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 cutting attachment rotates when the 

engine is idling the idle adjustment screw T should be 
turned anti-clockwise until the cutting attachment stops.

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 using the idle adjustment screw T, if 
it is necessary to readjust. First turn the idle adjustment 
screw T clockwise until the cutting attachment starts to 
rotate. Then turn the screw anticlockwise until the cutting 
attachment stops. The idle speed is correctly adjusted 
when the engine will run smoothly in every position. The 
idle speed should also be well below the speed at which 
the cutting attachment starts to rotate.

Rec. idle speed:

 See the Technical data section.

Adjusting the start throttle speed

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 (4 mm Allen screw) to increase or decrease the 
start throttle speed.

Proceed as follows:

1

Run the machine at idle.

!

WARNING! If the idle speed cannot be 
adjusted so that the cutting attachment 
stops, contact your dealer/service 
workshop. Do not use the machine until 
it has been correctly adjusted or 
repaired.

4 mm