Carter's psi ratings
You have it all wrong. I went through this with Summit and then called Carter. If it says "Maximum Pressure (psi): 7 psi" That is all it means, maximum. Doesn't mean anything for minimum. If you dig deeper and find it to says 3 to 7 psi and it's puts out 3 max, they say it is within spec! Just like it says, 3 to 7. It's at the low end but it's in there. I returned my first electric fuel pump from them and got another with a higher "range". BTW, I returned mine for a full refund and didn't pay shipping. Where they ask why it is being returned I put "The ad is misleading" and added the pump pressure story.
Young enough to learn ... too old to remember.