I had a paper inline filter, and even that, it was functional, but... the fuel tank was rusting. the paper filter allowed the smallest rust particles though, changing the color of the filter to a red color. Last winter, I took the carb off, and when I opened up the carb for spring cleaning, there was alot of Red dust in my bowls, etc.... I guess what I am saying is that the metal filter, might let bigger items though, where paper, gets the particle size to super small.