It sounds to me that your high end mixture is too rich. Which end did you tune first the high or low end? You will have lots of questions here about why this and that about engine tuning and setting. I suggest you read this article which will answer most questions on engine tuning.
http://www.rcnitro.com/rn/articles/super_tune.asp
There are lots of pages here with photos to help you. Just read them all before going full out with your new engine. It will not only explain what to do but why. Excellent stuff.