As an old fuel hauler & new member, I know #2 fuel oil is the same as diesel with few or no additives. #1 is thinner & I would not use it straight unless it is really necessary. (super cold, below zero). We seldom ran over a 50-50 blend. My location is N. Central Iowa. Bitter cold @ times & near constant wind. I really like this website & the info in it. Thanks to all of you!