I got a weird one here. We took delivery on a 301.8 in December. It was all ready to go from the dealer, and it had sat on line for a few months because they overstocked that model. It got low on fuel, so, I opened the cap, stuck in the nozzle and got a lap full. It seemed the pre screen in the fuel neck had a red colored substance almost looked like fiberglass resin and was accumulated right about where a full tank of fuel would be sitting. Everything ran fine but I called my sales rep, who used to be the serive manager at my Cat dealer. He came out and wanted to see what it was I was talking about, becxause much like many of you might be thinking, he had never seen it before. We arranged to have CAt pick the machine up and they gave me a loaner, where after 3 days, they had disassembled every part in the fuel system, changed them out and sent them back to Cat for an analysis. Everything is and always has run fine. I go to the job yesterday to fuel the machines and check progress and I get yet another lap full of fuel.... The Red stuff is back...The only thing I can pin this on is red dye fuels. Has ANYONE ever heard of, or seen this phenomenom before? It's a new one on me, and my obvious concerns are that if it is gumming up a pre screen, it will prematurely clog filters, lines, and so fourth, and, even tually, this can't be good for an injection pump or injectors. Any thoughts?