ORIGINAL: SAP_2000
Then we connected the fueling station and ran it at full power while the engine was at full throttle, eliminating any vacum on the suction side since the filling goes directly to the header tank and is pumping more than the engine consumes. Same result, 110K. Maybe 200 rpm's more.
This makes me pretty sure that the problem is not on the suction side of the pump.
Better than gravity feed, ran it with the fueling station giving 1,5 - 2 liters a minute into the header tank did not do any difference at all.