John,
I'm sure the membrane is silicone type material so wouldn't stand up well to fuel (other than glow) The fuel vapour is not an issue as the outlet check works very well and vapour can't be pushed back through the pump. Even when filling the tank it is forced to vent through the "bleed" that is provided by the needle valve in the current setup - Im working on a simplified bleed "tee" that is just an orfice - just have to determine the size.