I found this from Mikuni. Although the DF52-176 isn't listed, I have no reason to think it would not be the same as the other round models, at 35 liters per hour or about 9 and a quarter gallons per hour U.S.
http://www.mikuni.com/c-fuel_pumps.html
P.S. just be sure whatever model you choose the nozzles line up with the way the hoses are going.
P.S. P.S. I was thinking maybe this is not just one particular thing going wrong, but maybe a series of small malfunctions happening at the same time, i.e. "The perfect storm" syndrome.