Interesting question. It has a lot to do with how you use them. When I had smaller gear drive compacts like the 16 hp Yanmar with direct injection I tended to work at a high idle with brief blasts at road speed to dump or to speed up the loader. Working that way a gallon of diesel would easily last all day - or longer. Then I got a medium size 30 HP Yanmar with indirect injection and power steering plus a fancier transmission I'd use maybe 3 gallons a day working in the same manner. But I got more than 3x the work done in a working day
But on the
M59 I don't know yet. It does so much more than a 30 hp tractor can do that it isn't quite apples to apples. One thing I do know is that I can burn an astonishing large amount of diesel if I work the
M59 hard - especially if I work it hard with the autothrottle system on. Wouldn't be surprised to burn a gallon or two an hour in those conditions. I use it this way for difficult conditions like doing a lot of loader work or when plowing snow in 4wd.
On the other hand, if I am just doing moderate loader work and slow delicate backhoe work I turn the autothrottle off, regulate the engine speed with the hand throttle, and regulate the engine load with the hydrostatic pedal. Economy mode. Set up that way with the autothrottle off the
M59 motor spends a lot of time loafing and working at idle RPM. It still gets a lot of work done easily, but it also gets tremendous fuel mileage..I'm guessing it to be about half a gallon per hour at my much slower and more relaxed work rate. When working in economy mode the only time I bump the throttle off idle is when climbing a hill or going somewhere in high gear.
rScotty