Owning three 9u's pulling the same tillage equipment it vary some by how the fuel pump and governor is set as well as driving style.I am looking more at gallons per acre than gallons per hour,but with tillage work I would guess 4 gallons per hour is close.Having a hard nose with a 6s cat blade I would assume dozing would use a little less.
hello here is the nebraska test that show fuel consumption ,bruce oz
1955 d6 9u- http://digitalcommons.unl.edu/tractormuseumlit/1043/
1949 d6 9u -http://digitalcommons.unl.edu/tractormuseumlit/986/