Depends how well tuned the engine is but normally it is opened just a little for idle. Take a "T-pin" or a small paperclip (opened up) and insert it into the opening and gently close the barrel against it. Make sure the throttle trim is at least half-way up . That will be a good starting point. Yes, when the barrel is fully closed the engine will stop.
Depending on the radio you have you can electronically adjust the end-points and sub-trim to get full throttle, closed throttle right. If not then you will have to make any adjustments mechanically.