Does sound like lean mixture, before touching carb check easy stuff first, fuel filter in the tank blocked, fuel hose check for cracks or splits, check pipes to purge button, check purge button itself for cracks. The mixture screws on the carb have caps on them,you may need to pull these back to adjust the mixture ( anti clockwise to run richer ) you will need to check the rpm with a taco, max free running 12500/13000. This machine has an air head cylinder and is prone to ring gumming due to the fresh air being taken in through the air ports and cooling the piston, so check for good compression, good luck.
Husqvarna man, September 2009