1983 Maxim 750 gas pouring out the exhaust

Hi

I have a slight problem starting my bike this year, the bike will start and
run at an idle but will not run if you give it gas. I noticed gas was coming
out the drain hole in the left exhaust. I checked the No. 1 cylinder spark
plug and it is wet, the cylinder is cold which tells me it is not firing. I
checked the spark and it is good for that cylinder. Any ideas as what to
check next?

Thanks

Digger