In our jets that we fly we have found fibers from the felt in our post filters after the fuel pumps and in the fuel pumps themselves...Fact is that the fibers WILL find their way eventually to the filter screen in the carb. [:@]--I don't use felt for this reason-- A much better filter is a Festo filter...I would imagine that ZDZ might be afraid that if you use too restrictive a filter or the wrong type it could cause issues. The Festo filters flow VERY well...Here is a link to Todd at Dreamworks RC and the filters.....[8D] The first is a 4mm filter and the other is a 6mm fliter. (mm is the tubing size)--You can easily fit Tygon to these filters...They are rated at 50 micron filtration but flow EXTREMELY well as we flow much more fuel in our jets than in the gassers...I use these in my gassers...The 4mm works well with medium Tygon and the 6mm works well with the large Tygon...Just unscrew the ends, push on your tubing over the barbs and put the compression fitting end back on and your are in leak-free business!!!..Hope this helps.....Tell Todd that I sent ya...[sm=thumbs_up.gif]

http://dreamworksrc.com/catalog/prod...roducts_id=776
http://dreamworksrc.com/catalog/prod...roducts_id=777

Kevin