I get 1 pint in 1min 10 secs @ the carb ( was advised to pull the fuel pipe off the carb and measure it there, as opposed to timing it coming out of the tap ).
Just on that note, i bought a fast flow which was blocked, just check the 3 holes on the rubber seal inside to make sure they are not blocked. I took mine to pieces to found that who ever made it just pierced the holes in the rubber seal but they were still attached which did block it, hope that makes sense