I'm curious about this too. I think there should be a sticky thread on how to correctly break in an engine for unexperienced people. There may already be one somewhere on this website but have not found it. For breaking in an engine, I used to just run it rich for the first 5 tanks but this was years ago. Now people are saying there are all kinds of ways of breaking in an engine, so now I am not sure. I'm sure someone here will be able to answer this question.