Air in the fuel lines?

[rogergodding]

Anyone ever had this problem? I recently gave my son a 72 for his bday and it will run for a few minutes and then die. I went so far as to take my carb off of my truck and replace his with it. I also installed a glass filter close to the carb so I could watch the fuel flow..... plenty of fuel but same result. I kept watching and eventually saw bubbles in the filter. I assume it is one of the old hoses back under the cab or in the cab. Will look more tomorrow.