tropical36 wrote:
Usually, it's the upper 3/4, but to answer your question, fuel consumption will vary with the load and one could safely say that at full load, never more than one gallon per hour. We average about 3/4 gallon per hour in the heat of the day, with our old 5.5kw relic, at my best estimate. Same size new, should be a little better and with a newer an much larger diesel unit, I would expect about the same as an old gas 5.5kw.
Mine runs out of gas at about 3/4 tank but I think I might have a hole rotted in the pickup tube. Fuel consumption is exactly as you described. Mine's a 6.5 Onan antique (32 years old).