Husqvarna 326HS75, 326HS99 manual Maintenance, Carburetor

MAINTENANCE

Carburetor

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

After your unit has been run 8-10 tanks of fuel the engine has broken in. To ensure that your unit is at peak performance and producing the least amount of harmful emissions after break in, have your authorized servicing dealer, who has a revolution counter at his disposal, to adjust your carburetor for optimum operating conditions.

!WARNING!

The blades must be fitted before the hedge trimmer is started, otherwise the clutch can become loose and cause personal injury.

Basic setting

•The carburetor is set to its basic setting when test run at the factory. The basic setting is richer than the optimal setting and should be kept during the machine’s first working hours. Thereafter the carburetor should be finely adjusted. Fine adjustment should be carried out by a skilled technician.

NOTE! If the blades move while the engine is idling the T- screw should be turned anti-clockwise until the blades stop.

Recommended idling speed is: 2 700 rpm.

Recommended max. speed: See “technical data”.

WARNING!

! If the idling speed cannot be adjusted so

that the blades stop, contact your

service workshop. Do not use the

machine until it has been correctly

Operation

•The carburetor governs the engine’s speed via the throttle. Air/fuel is mixed in the carburetor. The air/fuel mixture is adjustable. To take advantage of the engine’s optimal output the adjustment must be correct.

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

L H T

adjusted or repaired.

Fine adjustment

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

Conditions

•	Before any adjustments are made the airfilter should be clean
	and the airfilter cover fitted. Adjusting the carburetor while
	a dirty airfilter is in use will result in a leaner mixture when
	the filter is finally cleaned. This can give rise to serious
	engine damage.
•	Carefully turn the L and H needle to the mid point between
	fully turned in and fully turned out..
•	Do not attempt to adjust the needles beyond the stops as
	damage can occur.
•	Now start the machine according to the starting instructions
	and run it warm for 10 minutes.

• The carburetor is equipped with three adjustment possibili-

ties:

H = High speed needle

L = Low speed needle

T = Idle speed adjuster screw

NOTE! If the blades move, the T screw should be turned counter-clockwise until the blades stop.

• The fuel quantity in relation to the air flow permitted by

the throttle opening is adjusted using the L and H-needles.

Turning the needles clockwise gives a leaner fuel mixture

(less fuel) and turning them anti-clockwise gives a richer

fuel mixture (more fuel). A leaner mixture gives high revs

while a richer mixture give less revs.

• The T-screw regulates the position of the throttle while the

engine is idling. Turning the screw clockwise gives a higher

idling speed while turning it anti-clockwise gives a lower

idling speed.

Low speed needle L

Try to find the highest idling speed, turning the low speed needle L clockwise respectively counter- clockwise. When the highest speed has been found, turn the low speed needle L 1/4 turn counter-clockwise. NOTE! If the blades move when the engine is idling, turn the idling speed screw T counter-clockwise until the blades stop.

L

+ 1/4

L

14 – English