Tractor Repair: pto generator and fuel economy, ford 3910, holland dealer

Question
I have a 1986?ish Ford 3910.  Per data, it has 42-48HP.  I am considering purchasing a 15kW PTO-driven generator for supplying our home and deep well during power outages.  I am unclear as to how long the tractor will run on a tank of fuel (13 gallon tank).  I read somewhere it will burn approx 2.5 gph, but unsure if this is true.  If it is, I may be better off purcahsing a gasoline powered gen instead.  Any insight to how long tractor will run on a tank of fuel with pto running at 540?

Answer
That would depend on how many watts of power you are using.  The more wattage you use, the harder the tractor is going to work and burn more fuel.  It would be almost impossible to calculate exactly how many gallons of fuel per hour because of the unknown load that will be on the tractor.  An operators manual or a New Holland dealer may have detailed Nebraska Test specifications on fuel consumption at rated rpm and load.  That would give you an approximate number.