Husqvarna 390 XP Owners Manual - Page 32

MAINTENANCE • You have now run the machine at settings of H =±0, H=+1/4, H=+1/2 relative to the basic settings. At full throttle the engine has sounded different for each setting. The H-jet is correctly adjusted when the machine burbles a little. If the machine "screams" then the machine is set too lean. If the muffler emits a lot of smoke and the machine burbles a lot then the setting is too rich. Turn the H-jet clockwise until the setting sounds right CAUTION! To ensure correct adjustment you should enlist a qualified mechanic who has access to a tachometer. The recommended maximum fast idle speed must not be exceeded. Correctly adjusted carburettor When the carburettor is correctly adjusted the machine accelerates without hesitation and 4-cycles a little at full throttle. 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. If both the L and H jets are set too rich it will results in acceleration problems or too low a working speed. Checking, maintaining and servicing chain saw safety equipment Note! All service and repair work on the machine demands special training. This is especially true of the machine's safety equipment. If your machine fails any of the checks described below we recommend that you take it to your service workshop. Checking the front hand guard Make sure the front hand guard is not damaged and that there are no visible defects such as cracks. Move the front hand guard forwards and back to make sure it moves freely and that it is securely anchored to the clutch cover. Checking the inertia brake release Place the chain saw, with the engine switched off, on a stump or other stable surface. Release the front handle and let the saw fall by its own weight, rotating around the rear handle towards the stump. 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. When the bar hits the stump the brake should be applied. Regularly check that the brake band is at least 0.6 mm thick at its thinnest point. 32 - English