Audio Systems: home stereo reciever, whole nine yards, size speakers

Question
I recently bought a pair of cerwin vega e-715 for my home theater system. I am running a pioneer vsx-d412 reciever that came in a surround sound package speakers the whole nine yards.  When I hooked the new speakers up I couldn't get good sound out of them until I figured out how to turn the receiver to 5.0 or 4.0 or 3.0 is as low as it will go.  as long as it is not on a .1 setting it turns off the sub and puts bass through my new speakers and sounds great for about 2-3 mins before it goes to overload and shuts down.  I have tried unplugging all the other speakers except the new ones and it still does it.  I tried putting thicker wires on em for less resistance but it still does it.  I bought the speakers used and they are in excellent shape, but the tweeters are missing out of the box on both units.  I have triple checked all of the wiring making sure none of them are touching, but I guess I was wondering if the fact that the tweeters are missing would cause this problem.  I didn't know if it was possible for this to not cause enough resistance or what.  I ordered the tweeters through cerwin vega today and when they get here I'm hoping that will be the fix I need.  But if you have any knowledge on this I would greatly appreciate it.   Thanks   Cole

Answer
i would have the speaker's internal crossovers checked, also check your settings real carefully, mine has a setting for 'full size' speakers instead of the small, limited range speakers that people normally use; after finding setting, my full size stage model jbl's sound just fine.....