Accurate consumption for my outfit (6.5mtrs 130hp Honda) averaged over 800 Nautical miles (920 statute) cruising in various conditions from glass flat calm to 2 to 3 meter swells. Speeds between 17 & 25Kn dependent on conditions was 1.13kn per ltr.
Or translated......about 18.5ltrs/hour
WOT figures are kind of pointless because your not going be running around at full throttle all the time, mother nature ain't gonna allow that