22" Murry, Briggs and straton push lawn mower?

Okay i just went to a salvage yard for mowers basicly and got a really old murry 22" with a old B&S motor. I checked the gas and oil there and put it on choke and after 3 pulls it started up and ran beautifully. I bought it, loaded it up took it home and tried to mow. (keep in mind this is a max of fifteen min from the time i started it and the time i got it home) I went to start it and nothing, pulled about 5 more times and let it sit just in case i flooded it. i went back out after about 15 min and pulled another 5 times, this time adjusting the gas from choke down to full and back. now i am here asking what is wrong with this mower. i just got it started at the yard and now it does not even want to fire. please help, its getting dark and i really need to mow my yard. Thanks