gas blowing out of top of carb

Hello everyone I am a new guy so bare with me. I have a 1997 John Deere 425 liquid cooled v-twin mower. I went to start it and it wouldn't start I pulled the breather off and it was blowing gas out of the top of the carb. Pulled the plugs and one side was dry and the other was soaked in gas. So what is my problem I need all the help I can get. Thanks

Gmacmopar