The plastic cover under the carb ( held with four allen screws) cannot be removed until you remove the cylinder, your best bet is to remove the the anti vibration spring screws, one screw at the side of the cylinder, one screw under the chain catcher, one screw above the fuel filler cap, remove the two bumper rubber screws, one at the bottom right hand corner of the crankcase under the starter, and one on the bottom left hand corner of the crankcase, remove the fuel hose to the carb, remove the throttle wire, you should then be able to remove the tank assembly with the top handle still connected. I would guess the fuel may be leaking from the tank breather, this is situated at the top rear right hand side of the tank ( next to where the fuel hose comes out ) this can be removed with out removeing the fuel tank, the early breather was two white pellets pressed into the tank, you will have to screw a self tapper into it to remove it, the later breather is an assembly with a nipple on top, a pipe then runs from it into the carb area, this can be pulled out with long nose pliers.
Husqvarna man, January 2010