OK, sounds like vapor lock and possibly???
Here's an old timer "try and see if this works", wrap the fuel line from the pump outlet to the carb with aluminum foil. Don't make it tight just put it around the lines hoses and loosely squeeze it around the pipe/hose. Here's the theory, aluminum dissipates heat as well as minimally acts as an insulator. So it will reflect heat generated by engine somewhat and if the line gets hot it will better dissipate the heat. Think of if your radiator had only pipes and no fins. Back in the 70s, before ethanol BS I had exactly same issue and wrapped lines with aluminum it helped greatly. Then I got a Moroso cool can and that solved issues. After a while I stopped putting ice in the cool can and just left the cover off and didn't have issues. Reroute you fuel lines away from hot engine sources, cheap method to help diagnose = dollar store aluminum foil.
