[bobcowan]

The fuel pump does not control the pressure. It just pumps fuel. Pressure is created by restrictions after the pump. Just like putting your thumb on the end of the garden hose.

If you're measuring >10psi at the carb, then there's enough restriction at idle to create that pressure. Make me wonder what the pressure is at WOT under a load?

A failing pump will move less and less fuel, and the pressure will drop. Doesn't sound like that's happening here.

I would add a return style pressure regulator as close as possible to the carb inlet. Maintaining a steady pressure with the proper volume is pretty important.