Originally Posted by Charlie12
But for now my guess is that there is a possibility of inconsistent engine-driven pump operation due to placement of the tank unusually far aft, which would explain why the kit does not provide a switch for the electric pump.
As has been explained here in the forum previously, the reason the electric pump on the RV-12 is operated full time with no switch available is to mitigate vapor lock.
This is the same reason the fuel pump is located at the tank in cars and trucks.
Vapor lock is much more likely when fuel is being pulled
through the system. With a pump located near the tank (and operating), it is pushing
fuel through the system and holding it at a pressure higher than atmospheric, making vapor lock much less likely.