Some people run a whole gallon through the engine for fear they might get a deadstick in the air if they take the engine up too soon. Some engines take longer to break in than the others. I like to run a tank or two on the bench at a super rich setting to let moving parts micro polish each other and to get a rough idea of where the needle settings will be. I run mostly YS four strokes, and they can hold a reliable idle after the first tank on the ground and can be taken up in the air for the rest of the break in process.