Gas line size

[tsubaki]

I'd do like phat said!
I can't remember the usual breakdown as to hose size per cylinders used.
Seemed like it was 3 cylinders can run off of 5/16 and 4 cylinders might be able to but the 6 cylinders need 3/8.
I'm sure you will find a smaller line size at or in the engine than what comes from the tank, if you try to rationalize it that way. Figure trying to suck through a small straw and the volume you get compared to a McD's straw.
Adding more hose length and another filter should compound the problem if the hose size was borderline.