Its running too lean, easy things first, clean replace the filter in the tank, make a small adjustment too the L screw on the carb ( up too half a turn out ) if no better it may be dirt in the carb, remove and clean out the screen under the pump cover, if still no better it could be an air leak, check the rubber boot between the carb back plate and the cylinder for cracks, no better change crank seals.
Husqvarna man, May 2010