Ok hope this helps, I just got my mini a few weeks ago and had trouble breaking it in as well......... First off if its cold outside your going to run into problems getting it to run right, when you first get it started you should let it idle for at least 4-5 minutes to let the engine warm up.......Do you have a temp gauge? If so you should use it to check the temp on the engine before you even try to throttle it, I let mine get to as close to 200F then I started to run it........
The settings should be 2 1/4 turns counterclockwise from the closed position on the high speed and 2 1/2 turns on the low speed needle from the closed position........
Check your idle screw as well, make sure you have the 1/16 gap..........
Trust me I had similar problems breaking in my Mini, but the key is to be patient.........
Here is a thread on AE's forum about the problems I was having:
http://www.aeforums.co.uk/forum/inde...showtopic=3932