On a computer radio, set your linkage so when servo is centered, the throttle arm is centered, then use your end point adjsutments to set full open and full closed without any binding of the linkage. should not hear servo buzz at any time in the throw. If you can't get the end points close to full throw, adjust you linkage to different hole untill you can. The other thing is you might not have enough prop on that motor and its reving up to quickly. You should be somewhare between 9K and 10K static ready to fly.