Vapor lock, hot fuel pump

[walker]

I am having troiuble with my stock mechanical fuel pump boiling the fuel. When it gets hot out (130*+ on the highway) the fuel pump stops pumping. I can duplicate it at home by just letting it idle with the hood closed for a while. The fuel in the clear fuel filter disappears and the squirts from the pump get smaller and smaller then just stop. I poured a little cool water on the fuel pump and it stars pumping immediatley. I replaced the steel line going to the carb with a rubber hose, but it didn't affect it at all. I also checked the fuel cap too.
Any suggestions would be appreciated. I would like to not have to change to an electric pump though.
Thanks, Andy.

[Tx Firefighter]

I'd try insulating your right side exhaust pipe if it's anywhere even close to the fuel line in the framerail.

Usually, that's a big culprit. These trucks didn't have the problem when they were new, so it's likely something that's been changed or modified over the years that's causing the problem.