Citation Trailers If I Store My Boat Outside This Winter Is Better To Fill The Gas Tank Or Empty It?

If I store my boat outside this winter is better to fill the gas tank or empty it? - citation trailers

The boat is the trailer to the ground. Northern Ohio.
Schedule 20-foot Captain's Cabin. Gas tank is next.
I finished the preparation of the winter mercruiser instructions, but no information on the amount of helium gas.