Johnny,
I hate to contradict your instructor, but I have ran an LN-25 off of both my machine, a Ranger 250 capable of CV output, as well as off of a Pipeliner capable of only CC output, and running it off the pipeliner kicked the living crap out of running it off of my machine, though it was a little harder to set. I realize that perhaps you are too strapped to buy an engine driven, but the principle is all the same, amps are amps and volts are volts, no matter how you get 'er done. The machine is MADE for a CC across the arc input, and like I said, its a good machine. You might wanna research a little more into this and understand a little more before you metaphorically throw away all the M&M's that have W's written on them if you know what I mean...
Just a thought
G. L.