Husqvarna 450 e-series Owners Manual - Page 31

MAINTENANCE General The user must only carry out the maintenance and service work described in this manual. More extensive work must be carried out by an authorised service workshop. Carburetor adjustment Your Husqvarna product has been designed and manufactured to specifications that reduce harmful emissions. 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 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. Fine adjustment should be carried out by a skilled technician. Rec. idle speed: See the Technical data section. Fine adjustment 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 counterclockwise 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. Checking, maintaining and servicing chain saw safety equipment Note! All servicing and repair work on the machine requires special training. This is especially true of the machine′s safety equipment. If your machine fails any of the checks described below we recommend you to contact our servicing dealer. Chain brake and front hand guard Checking brake band wear Brush off any wood dust, resin and dirt from the chain brake and clutch drum. Dirt and wear can impair operation of the brake. Regularly check that the brake band is at least 0.024 inch (0.6 mm) thick at its thinnest point. Checking the front hand guard WARNING! Contact your servicing Make sure the front hand guard is not damaged and that ! dealer, if the idle speed setting cannot be there are no visible defects such as cracks. adjusted so that the chain stops at idle. Do not use the chain saw until it has been properly adjusted or repaired. Correctly adjusted carburetor When the carburetor is correctly adjusted the machine accelerates without hesitation and the machine 4-cycles a little at max. speed. It is also important that the chain does not rotate at idle. If the L-jet is set too lean it may cause starting difficulties and poor acceleration. If the H-jet is set too lean the machine will have less power, poor acceleration and could suffer damage to the engine. Move the front hand guard forwards and back to make sure it moves freely and that it is securely anchored to the clutch cover. 1151081-49 Rev.2 2008-02-27 English - 31