Rough Running On Hot Days, ...already relocated the fuel pump. Options

[7TPorsh]

Running dual webers. Bot a Carter fuel pump, a new line and relocated the pump up front in the spare tire area. Ran new hoses, aluminum line through the tunnel and new filters to the carbs.

When it's hot, maybe over 80 degrees out; the car starts to misfire and buck after I have been driving about an hour. It will start missing then it gets unresponsive to the pedal. Barely idles and then shuts off.

I have to sit about 20 minutes to cool off then I can start up and drive for maybe another 5 or 10 then it starts again.

Cool weather it runs ok. I did the fuel pump thinking it would fix this. It did get a little better but during these couple weeks of hot weather it stated up again.

Hoping this is a simple fix...touching the carbs is a scary task for me to even think about. Don;t want to screw it up worse.

I don't have any type of temp gauges at the moment.

['73-914kid]

Correct. They are between the head and the intake manifold, and would require the removal of things to install them. They are readily available through the usual parts supply sources.

I think this may be adding to the problem, but it most definetly is not the entire root cause. boiling fuel would likely create a small problem on throttle transition and cruise, but I think you're problem is more rooted in the fuel pump/pressure/ flow area from an electrical standpoint.

Again, You might want to look into getting an inline fuel pressure gauge to ensure that you aren't losing pressure as the ambient temperature increases.

One thing also to listen to with the carter pumps. They make distinct noises, as most electrical pumps do. When the car hasn't been run in a while, and fuel needs to fill the float bowls, the pump will have a higher pitch whine to it. As the bowls fill up, and the floats close the fuel inlet valves on the carbs, the pitch of the fuel pump will drop to a deeper growl as it it building pressure against the valve. Try to recreate the problem, but this time listen to the pitch of the fuel pump. If the pitch is different from cold-hot, you've narrowed down your problem.