The idle speed on a Husqvarna chain saw allows just enough fuel into the carburettor to keep the engine running. You adjust the idle speed by turning a screw that controls the amount of fuel going into the carburettor. Adjusting the idle will also cause the chain to start spinning, so make sure that no part of your body is in the way of the chain, and keep others away as well when you're making this adjustment. Also, it is dangerous to operate the Husqvarna if the chain spins while idling.
Set the Husqvarna chain saw on a flat, firm surface outdoors. Pull on the starter rope to start the engine. Squeeze the throttle slightly for one minute to let the engine warm up.
Locate the "T" screw on the operator's left side of the chain saw, near the air filter cover and throttle handle. Insert the head of the small screwdriver into the slot of the T screw.
Turn the screwdriver clockwise until the chain starts spinning. Stop turning it clockwise and turn it slowly back counterclockwise until the chain stops spinning. Locate the highest idle speed before the chain starts spinning.
Never operate a chain saw with a chain that spins while idling. Take your chain saw to a service dealer if you can't adjust the idle to make the chain stop spinning during idling.