What I do when I am setting up the throttle is this. I put the trim all the way down, stick all the way down. Then I make sure the throttle barrel is closed and then I tighten up the throttle pushrod. After the mechanical linkage is set, then I move the trim to the center. This will normally give me a good idle speed and when I land I can move the trim down to the bottom to shut down the engine. I am using a DX-7 and it has throttle recovery on it. That means when I move the trim lever all the way down to kill the engine all I have to do is bump the trim lever up and it returns to the setting I had before.