Hedge Trimmers

I have a fuel problem with my 326hd60 Hedge Trimmer. After a while the unit begins running poorly and if I take the fuel cap off the gas will boil out of the tank. I believe the fuel is getting too hot and boiling, we call it Vapor Lock in my antique car. I use this gas in other 2-stroke engines and have no trouble. Is there a way to correct this, maybe run a longer fuel line, or gas made and sold for 2-stroke use?