the aircraft, a microlight, is a high winger with tanks in the wings but it is not a Rans S6. Nor a Skyranger, nor an Escapade, nor a Kitfox, nor an Avid, nor a C42, nor a Thruster, nor an X'air, nor an AX2000, nor a Kolb, nor a CT, nor a Dragon ........
I have not had a 912 fuel pump to bits to see how it works but I think it may have a spring pushing the plunger and fuel forwards. The cam follower on the gearbox pushes the plunger backwards, the length of the stroke will depend upon the volume of fuel used since the last time the cam came around. The pressure will depend upon the strength of the spring?
It may be very different.