For anybody not familiar with Boyle's Flask, it's a reservoir of water connected at the bottom to a tube such that the water infinitely pours into itself. Essentially, perpetual motion. And it's only a theoretical concept.
With that in mind, watch this quick video:
Done? OK, now, can you tell me what the video did wrong?
If you answered used an obscure method to trick the viewer into thinking it actually worked, you're 100% correct. Based on a few other videos which debunk the scam, fluid dynamics don't work like that, even for a carbonated beverage. When put into an actual constructed Boyle's Flask, without a hidden motor, liquids, even carbonated ones, will eventually reach an equilibrium point where the surfaces of both liquids are at the same height, WITHOUT pouring back into the flask. Even if the liquid is drawn out so that it reaches the end of the tube, instead of flowing down into the flask, the difference in pressure will actually pull the liquid back through the tube until it reaches dynamic equilibrium once again. Of course, this isn't saying perpetual motion is impossible, but it is saying that this specific instance has been largely disproved by actual science.