Out of Fuel - Siphoning Fuel
A siphon. You could carry a generic clear plastic hose and do it the old-fashioned way, but there are a few products on the market that have zero possibility of you drinking gasoline and inhaling noxious fumes.
Most of the specialized siphoning fuel tools have a one-way valve that you repeatedly dunk to suck up fuel until there is enough in the tube to start flowing on its own, some even have little hand pumps to assist you. No matter which tubing you chose, make sure you have some sort of receptacle for the fuel – a crushed plastic water bottle works fine.
If you think that running out of fuel will not happen to you, remember you could always make new friends by carrying a small rubber hose and a siphon tool.