Any genny has the potential to leak if laid on it's side for extended periods of times, just the way they are designed with the placement of the air hole.
With the fill screw in there's much less potential, the only way for juice to get in the cap is around the wick but it still can happen. With the fill screw left out it wicks better in some cases but then you have 2 points of entry for juice into the cap. It's usually minimal if it does and it takes quite a while of being left on it's side for it to happen.
With the fill screw in there's much less potential, the only way for juice to get in the cap is around the wick but it still can happen. With the fill screw left out it wicks better in some cases but then you have 2 points of entry for juice into the cap. It's usually minimal if it does and it takes quite a while of being left on it's side for it to happen.