Does the tank only have one air hole or several?
Try closing it all the way and see if the adjustment is loose enough to let the amount of air you desire through. If not, open the adjustment slightly and try again. Keep doing so until you get the draw you want.
Keep in mind that, with a tight draw, the vape will be warmer at your normal wattage.
You may have to also turn down the wattage, but if it is too low then you will not get enough vapor and the coil may flood.