Carb flooding intermittantly...??

okay. bought a gauge, lowered it to 5.5 psi. went to ajust the float levels; the levels were already at the bottom of the hole where they were supposed to be. thats' fine and dandy, but the screws on top to adjust the floats were all the way closed. they couldnt be screwed down any farther. wouldnt holley, at default, allow some adjustment? it seems strange that they would be adjusted correct at the all the way down postition. or am i just a worry wart?