Jim- I run a felt clunk, the kind used in chainsaws, etc. and I haven't had to clean a clogged screen in years. Believe it or not your vent line will suck in debre depending on your runway. I also run a paper filter on my gas can out line. The only time I clean the screen is when I have to replace parts on the carb, (and it always seem clean enough) or the engine was not running right because I did not use a felt type clunk.