[lostagain]

Hello all I have a issue with the yarf dog seems my son could not wait for me to get home and hooked battery up backwards and tried to start it.well it popped the fuse replaced fuse lights come on engine cranks but will not start. but if i take air cleaner off and chock with hand it will start and stay running until i remove hand.would this be a cdi issue? any help would be greatly appreciated thanks.