Stating the obvious this is fuel starvation, things to check, fuel filter in the tank blocked, fuel hoses leaking, non return valve in the purge bulb not working, whip the muffler off and check the condition of the piston through the exhaust port, strip carb clean internal filter, check diaphram condition, always check the easy things first before going on to the carb strip down.
Husqvarna man, March 2010