Stalling every couple rounds ?

My murray 46581x92a is dying instantly every couple rounds around the yard,seems you let it cool a minute and it starts again for a couple rounds ,runs good when running ,doesnt act like running out of gas ,I have been through the fuel system multiple times and convinced it is something else ,any ideas and how to check..the engine is a briggs and stratton model 313777..can anyone help,ohh ,does seem to be firing at plug though