HELP! Compressor now trips breaker on start up??

Yeah, start-up can typically pull 5 to 10 times as many amps as when running,depending on load. 5 hp is 5x749=3745 watts. 3745/120 volts=31.2 amps.So trying to start under load, on a 20amp breaker is pretty iffy.You need to drop the air pressure in the tank below the set-point of the cut-in device. Then the compressor will start like it used to.
-Also, you probably shouldnt try to pull those 31 amps through a typical light switch, unless maybe if youre switching the neutral side.
-I think putting a ball-valve in the airline at the tank is a better idea, and leaving the beast electrically connected. And,of course,eliminating all pre-valve leaks.
-Oh yeah,Typically the stated hp on the motor, may not correspond to the math exactly.The best idea is to get an induction amp probe, and find out exactly how many amps your motor is actually pulling; both when starting, and when running. Your motor may normally only pull 5 amps when running but pull 25 or 30 or more during start-up.Typically the start-up period is so short that the breaker doesnt respond to it. However when attempting to start under load the time period is/may, be long enough to trip it.If you treat the breaker this way for too long it will "get old" and eventually fail.
-It would be like trying to start your car engine, in 4th gear(m/t), with the brakes on.Theres nothing wrong with the system, except the load.
-Hope this helps, AJ