what do you mean it leans out??? usually when a motor leans out, it acts differently,do you mean keeps heating up???? if its a new tank, then its going to be a motor issue, whether its tune, or maybe a air leak.. I had a motor run great good when i fired it up, run better by half tank, then run worse and loose a little power towards bottum of tank, that was due to a lean engine.. once i retuned it, it ran great..