Gas gauge float tuning

[greg g]

Put in a new two wire guage, it shows just under 1/4 full when there is only just over a gallon or so left.  Last time I filled it the gauge was still showing 1/4 tank. It took 15.5 gallons to fill.  Considering a 17 gallons capacity, quarter tank should be just over 4 gallons.  So do I bend the float arm up or down?  Seems I should bend it so the float is higher so it will drop further nearing empty.