Reconnect the vaccum, non vaccum or breather hose and try to keep it running, then spray some starter fluid on both ends of the crank next to the seals and see if the engine revs up. If it does you probably have a bad seal. Wouldn't put the idea of a bad seal on the tube that could suck or blow!
As for the running issue. Needs a good carb cleaning and fresh gas. You can maybe try and keep the choke on and keep pouring gas in the cyl. til it keeps running. Don't keep it running too long in this warm weather so you don't overheat it.