Not worked on one of these before, however the thin pipe is nearly always the fuel inlet which will have a fuel filter on the end in the tank, this will go to the fuel inlet elbow on the car, if this machine has a primer there will be a pipe from the other side of the carb too the suction side of the primer, there will then be a pipe from the pressure side of the primer and back into the tank, so the primer pulls fuel from the carb into the bulb and back to the tank.
Husqvarna man, April 2010
