Husqvarna only runs at half choke - Husqvarna 28cc Hand Held Blower HVH 125B

Sounds like the mixture is out - trial and error really or take to licensed repairer they will let you know if you need a new carb or whatever is stopping it from running normal :)
Good Luck!

this is a sure sign of a fuel blockage some place !! id start with fuel filter and air filter and then look closely at fuel lines for signs of collapsing when running (CAREFULLY!!!!!) then move on to cleaning and resetting carb jets

remember choke richens fuel/air mix so if it needs choke to run then it's being restricted in fuel supply

Try opening the choke half way as soon as it starts then all the way open in a few seconds... It only needs the choke to start and should run fine in less than a minute after idleing with the choke not engaged...

Never pull the starter more than 3-4 times under full choke. Pull 3-4 times on choke, push in to half choke and pull, should start.

The next step is to richen the fuel mixture on the H screw on the carb, there is a special tool required to turn the adjuster screws because they have a splinr rather than a screw driver slot, the tool is part np. 530035560 unscrew tthe H screw 1/4 turn anti clockwise.

it may be the idle jet is plugged there is a needle and seet on most of them. have you tried half choke sometimes the will clear on their own

Possibly a fuel starvation issue, incorrect fuel air mix or an air leak within the fuel system

Fuel starvation, replace the fuel filter in the tank, check the fuel hose up to the carb, pay special attention to where it leaves the tank as they do perish, failing this then there is dirt in the carb.

check the fuek lines for hole and leaks, check the fuel filter and clean if necessary. remove the carbuerator and inspect the gasket; it should be soft and flexible, if it seems hard or brittle replace it. clean the carb with carb cleaner sray (available at any local auto parts store) and compressed air. make sure you get inside the small fuel rail holes.