Gas does not drain back out of the carbs, it's physically impossible with a needle and seat that are above the fuel level.
It evaporates from the heat and sitting.
Eddie's are more prone to it because of thier design and the fact that they hold less fuel in the bowls.
The fuel WILL however drain back down the fuel line till it reaches the level of the fuel in the tank leaving air in the line that it has to refill with fuel before it is able to fill the carb bowls.
Electric pumps solve all that, and I would never go back to a mechanical pump because of it.
