i'd still keep at least a 1/2 tank.... a sealed tank obviously is now about
95% internally impervious to rust [when they do rust, it starts around the
sending unit ring- which is unfortunately close to the highest point in the tank
where condensate starts].. as rust forms in a sealed tank, it causes the sealer
to bubble away just as hidden body work does on the lower body of quick-job
restos.... the only other woe would be an extreme collection of moisture that
condensed and formed a small water puddle at the lowest point of the tank- a
sealed tank creates an interior with lower cohesion-tension properties, thus a
water droplet will makes its way to the lowest point faster- instead of adhering
to the interior metal above the fuel level and starting the corrosion process-
the negative aspect is that enough of a puddle can get sucked up- and though
water-injection will add hp under controlled situations, a fuel line with a
coulumn of water in it isnt such a good idea!
if concern is that great- its best to drain the tank completely and leave
it vented for the storage duration- that includes blowing back the fuel line
from the pump connection so you dont end up with a fuel line full of stale gas
as well