[Aerkuld]

If it's been left with gas in the tank and in the carburetor then my money is on it being clogged up with gunky fuel deposits. As all the useful stuff evaporates off the gas it leaves all the horrible stuff behind and it can get quite syrupy. See what Robert said about cleaning it out. Get some decent carb cleaner and spray it in there and give it a good soaking. Maybe leave it in there overnight and try starting it again the next day.