I had the same problem with one of my motors, can't remember which one. But I did notice the needle was very easy to turn. I mean, you could turn it with your fingertips no problem. But it didn't dawn on me until one day while trying to tune, I noticed the high speed needle had gone flush and I knew I didn't set it there. So that was when I ordered a bunch of o'rings from ashford hobby and he helped me get the right ones. After replacing them, the problem was gone. And, you needed a good grip on the screwdriver to turn the needles.