The break-in was simple. It was ready to go at about 5 tanks and I was leaned out and rippping at around half a gallon-I love this engine. My only complaint is that I can't keep the front wheels down. As for yours, lean the HSN some until you get it to shift into 2nd. Leaning the HSN out also leans out the LSN too, so if it still wants to die at 1/2 throttle, lean the LSN a little....it shouldn't take much. Always do the HSN and LSN adjustments a little bit at a time.....and don't mess with the MSN because it's really not needed.[8D]