It sounds like the adjustment bolt on the CSV is tightened too much. As long as you are using more than 1 GPM the pump should not cycle at all. If using less than 1 GPM it should cycle slowly, not fast, like on for 2 minutes and off for 2 minutes, even with the 4.5 gallon tank.
Those Gator pumps don't usually build enough pressure to work with even a 30/50 pressure switch. With the switch at 20/40 the CSV should hold 30 PSI while using as little as 2 GPM.