what is the tuning settings on the carburettor?

Without knowing the make and model of the machine, i would advise setting the H screw and L screw at one turn out from closed, they are both fuel not air screws, so the more you undo them the richer the mixture gets, the L screw will adjust the mixture from idle to half throttle including acceleration, the H screw will adjust the mixture from half throttle to maximum revs,you realy need to know what the manufacturers recommended max free no load speed is before adjusting carb settings, too high engine rpm will cause an engine seizure, most hobby saws run at about 12000/12500, an engine taco is needed to check this, you will need to fine adjust from the basic settings. The third screw will be the tick over screw, there is no basic setting for this, the saw should tick over steady without the cutting chain moving around the guide bar

Husqvarna man
August 2010