technically, it does run out of fuel. youll notice depending on if you negdiff the tank when it first arrives or if you spend like a week on it the fuel in the yellow canisters will be different. its not random, it actually expends fuel to fire
though, ive never wasted the time to find out if it actually STOPS being able to fire once it runs out since it uses fuel so slowly and has 2000 units of the stuff. i suspect not? i agree it could be tweaked to use fuel faster but im also not sure what should happen when it does run out aside from.. not being able to fire.
although, if you have high reputation with the campsite aliens theyll protect you from it