Do you have a boost gauge?What's it reading?Have you tried adjusting the max fuel screw?
So you have tried to up the max fuel screw, but the idle screw hit bottom and you can't lower the idle any more? Sometimes we lift the accel lever and rotate it to another spline. That moves the lever back to where it will need the idle screw moved out to catch it earlier. Then adjust the pump max fuel screw until the idle hangs, then back it off a little.Have you done a governor mod to it yet?