Yup... a clubmate of mine had one, it did not even SEE the fuel consumption of a DLE 35 cc 2-stroke.... At full throttle it appeared to measure "something" but at anyother throttle setting the figures just jumped up and down.

As Dave said, it is for turbines or really large engines...It only works if minimum fuel consumption is above 20 ml/min. That means, at idle the engine should consume that in order to produce usable readout. My largest engine ( the 65 cc radial) barely manages that at full throttle...