Those threads are good info but nothing to worry about. air cooled gas motors have always needed air to cool them. This means to get it in the air as soon as possible for proper breakin. No, the prop does not provide sufficient cooling!
As RickP states, use the Lawnboy for 4-5 gallons and fly! A good prop to start is 22x8 or 22x10 and move to a 24x8 after breakin.