Help me: External marine tank on Champion 2000 watt gen.

i don't have the web link
but i think 'supergen products'
has an extended run system available

i'm guessing that if you modifed the gas cap
and started with a full on board tank, an elevated gravity feed might
move fuel from the elevated tank to the onboard tank

a primer bulb, and filling the line before attaching to the genset, would decrease air and internal pressure