My Marquis Spa <Pacific Marquis> is about 10 years old. We just got it from a friend who only had it in use for 2 years. We got it to work 3 times. It ran for about 30 minutes each time. Then the gfci tripped. After about 12 hours, we got it to turn on again. Now, it shuts off about every 4 minutes. My pump is making a humming sound too. Do you think if the pump is going bad, that will cause the gfci to keep tripping? Since the pump is so old, would I be better off to just go ahead and get a whole new pump? Thanks!

If your pump is humming, and not pumping water, then it's definitely bad and possibly causing this problem.

However since this sounds like a new installation, you really need to take a look at this (Item #2): http://spasupport.com/electrical/main/overload.html

Also this: http://spasupport.com/electrical/main/burnedwires.html