problem with a /6 carb..

It sounds like the float need to be set to me, it sounds like it is just letting the gas bowl stay half full, if it was in the tank it would not have hesitation that fast.
Take the top part of the carb off, you will need to un hook the accelerator pump linkage I believe, and you can see the float and the needle that shuts the gas off
I see it is a 75 model, Give a time and I will take a picture of the carb, is it a two barrel?