Doc,
Let's look at a 10 BHP diesel that has a specific fuel consumption of 300 grams per kilowatt-hour (300 g/kw-hr).
1 gram = 0. 002204623 lbs,
so 300 g/kw-hr = 0. 6613868 lbs/kw-hr
1 BHP = 0. 745699 kw,
so 0. 6613868 lbs/kw-hr = 0. 49319548 lbs/BHP-hr
Since this is a 10 BHP engine, it will consume 4. 9319548 lbs of fuel per hour.
Since #2 diesel weighs approximately 7. 462 lbs per gallon, this equates to fuel consumption of 0. 66094 gallons per hour.
Rusty