I have just got my new EFW2 and it’s showing the same problem, no amount of adjusting of the tension screw makes a difference, from totally slack to all the way to causing the rubber o-ring to distort. However there is light at the end of the tunnel, with the lid off the wheel performs far better, almost 100%, with it on and screwed down it completes it power on cycle successfully but then goes into crazy mode after the first filter change and ends up just spinning with intermittent pauses to regain its breath for a few seconds. From what I can see the cause of this is the “wave washer” that is between the bearing cap and the case lid, it appears to be too tight when the lid is tightened down. With the lid on and this removed it works flawlessly, but naturally not usable as the filter wheel is now free to move perpendicular to its rotation, which will play havoc with the image quality no doubt. I’m going to try changing the wave washer for a slightly less stiff option to see if this helps. I’ll report back once I have tried this.