* Rollover Valve: Most modern vehicles, including F-150s, have a rollover valve in the fuel tank. This valve closes to prevent fuel spillage in the event of a rollover accident. A siphon hose won't be able to overcome this valve's closure.
* Fuel Tank Baffle: The fuel tank has internal baffles designed to reduce fuel sloshing during acceleration and braking. These baffles can interfere with the siphon process, making it difficult to get a consistent flow.
* Fuel Pump and Sender Unit: The fuel pump and sending unit assembly are located inside the tank. These components take up space and can obstruct the siphon hose's ability to reach the bottom of the tank, where the fuel is.
* Fuel Line Design: The fuel lines and tank design are not conducive to siphoning. The lines are typically well-sealed and designed to prevent leaks, making it difficult to create the necessary vacuum for siphoning.
* Fuel Level: Siphoning requires a certain amount of liquid to create the necessary pressure differential. If the tank is nearly empty, there won't be enough fuel to sustain the siphon.
In short, the engineering of the modern fuel system is deliberately designed to *prevent* siphoning for safety and security reasons. Attempting to siphon gas from an F-150 is not recommended and may be illegal.
