I need help. Think I flooded my bike

I just bought a 1980 Yamaha XJ650G (original). When I bought it they guy said it just needed a new battery because the one he bought wasn’t the right size. So had an ingenious idea to hook up the battery to the connectors inside the bike. Good news is the bike tried to start. I think it was old fuel. Bad news is I left the petcock on Prime (I’ve read online that if it has a Prime option it’s vacuum fuel delivery). So I’m trying to turn it over and all of a sudden I smell gas so I look over the seat and gas is pissing out of the overflow tube which comes out of an air box/air cleaner thing. I think I flooded the engine. I’m not 100% sure what the problem could be however I’m 99% it was because I left it on Prime for too long. Do you think letting it sit overnight to let any built up gas evaporate would fix the issue? I’m planning on replacing the spark plugs and adding fresh gas anyways. Thanks! via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/f71v4z/i_need_help_think_i_flooded_my_bike/?utm_source=ifttt