RE: old gas?
no, fuel of that age should not make a difference. is your glow ignitor fully charged ? is your glow plug lighting up ?
pull the glow plug out and plug it into the end of your ignitor to make sure it glows.
have you ran this buggy before ?
it's possible that the carb setting could be that the carb settings are set too rich and the engine could be getting too much fuel.
is your idle set ?