Fuel pressure 100% will bend the tangs for the float on some carbs. Huge problem on the older Jeeps with the inline 6 and the Carter carbs. 6 psi is all it takes with that carb. The needle gets forced back The floats are all the way up and there's no movement left. You can put brand new float and needle and everything in there, and if it's over 4 PSI it does it again less than a month. I've personally witnessed it numerous times.