I saw the video, and the guy is using crankcase pressure. That gives me the same creeps than the Perry pump, plus the cut and patches he did, and still seems that the engine is not stable at any position of the tank, although I have to accept that he moved the tank way up or down, more than reality, but generally speaking is not a bad solution. Still there is the size issue, which in the video looks rather as 1.5 x 1.5 in or a bit less. Interesting is that he uses it in a 4.5cc engine, which between the OSs .25 and .35. Other thing I didn't notice before is the carb type. Will try to get more info about the carb size. I also noted in the video about the vent issue. will keep looking into this solution before deciding which way to go.