ORIGINAL: AllTheGoodNamesAreTaken
Perry recommends only using a T inline between the output of the pump and the carburator IF the engine is rich at midrange. If it is decided that a T is needed, no checkvalve should be used. The pump will provide enough pressure/flow to eliminate any possibility of the carb sucking air from the vent.
Jeff,
In my scheme the checkvalve is used for constant pressure, not to prevent the carb sucks fuel from the ventline!
The flow of the pump always has to be more than the engine needs, the checkvalve reduces the pressure a little above barometric pressure.
The principle is the as the threshold voltage of a diode!.
Cees