The Evo engines ARE NOT, I repeat, ARE NOT broken in at the factory! They are "run in", supposedly to set the carb. But, those settings are not going to be accurate for every region of the country. I've read so many posts about "my Evo ran like crap out of the box, yadda, yadda, yadda". Well, if I am flying at 760 ft above sea level, and you are flying at 3700 ft above sea level, OF COURSE your engine is not going to run like mine does, and your setting are going to be way different than mine! People, it's not hard to figure out that one setting won't work for every engine out there. That's exactly why the needle stops on the Evo engines are made so that the user can re-adjust them to get more adjustment range. If one setting worked on every engine they made, they wouldnt need to have adjustable needle valves and idle screws in the first place, now would they? As far as break in, I personally broke in my Evo .46 (and now my Evo .61) just like any other ABC type engine. I ran 5 tanks of fuel through the .46 before I ever mounted it on the plane. When I mounted it, I set the needle valves (yes, I had to move the stops to get the perfect setting), and the engine ran perfectly. The engine has only quit in flight twice, and that was because I had the throttle trim set incorrectly on the radio. Regardless of what the factory says, a good break in goes a long way!