Hi, I'm a new member. I just bought, what is believed to be a Fantic 305 but really not sure. It's been stood a few years, desperate to use it. The problem is the engine starts, on choke but then runs erratically. I'm not sure if the carb has been messed with. Does anyone know the amount of screws 'out', the slow running jet. Anyone know anything about it? How can I tell what model it is? Wookey