You don't need to worry about the size of the line. I would suggest connecting "in" to the wipers. To me that would be air in and that would be vacuum. On my unit, the in on the fuel and the in for the air are on the same side of the pump, towards the rear of the engine.
Regarding your test, you should be able to feel vacuum on the fuel inlet too, for sure. The lever moves quite a bit and it takes a lot of force to get it to move. That is why I suggested pushing it up against something like a work bench.
Last edited by truckernix; 01/29/2012 2:31 AM.
