Gyro: the force of gravity keeps your a$$ on the floor.
The kind of force we are talking about is called "elastic potential energy"
This is the force required to keep the springs (don't forget the vacuum line is a spring as well) at tension. Energy is expended to apply this force.
This may (or may not) help explain what I am talking about:
When I was in HS our science teacher attempted to demonstrate how water will boil in a vacuum. He put a beaker of water under a bell jar and began pumping the air out with a vacuum pump. Nothing happened. The spring (the air in the jar) was too strong for the vacuum pump to lower the vacuum enough to boil the water. I suspended a balloon in the jar full of water, inflated it some to displace some water, hooked the balloon up to the same vacuum pump and turned it on. Nothing happened for some seconds, then all of a sudden the balloon deflated and the water boiled off enough vapor to displace the volume of air in the balloon. Why? Because the spring (air in the balloon) was a lot smaller than before. The vacuum pump had to keep applying force to maintain the vacuum in the bell jar. I closed the valve on the vacuum line and shut off the pump. Then the force of the difference of pressure, in this case elastic potential energy, kept the balloon deflated.
My point here is that energy is used to keep tension on any spring. If I had a vacuum gauge I could calculate how much energy is needed to keep the petcock open.
Vacuum in a carb can be created in two ways: resistance to airflow caused by the air filter, and air flowing over an orifice in the carb. Putting in a less restrictive filter allows more air which pulls more fuel (assuming your jet system will supply it). Same thing if you plug the orifice, as you do when installing raptor.