They filter with the third port is a return port, it is supposed to keep the fuel moving and cooler, it helps prevent vapor lock and stuff like that...
Is this a simple swap out? I might be looking into doing my own tune-up and would like to replace the fuel filter since I dont know when it was last replaced.
DanG - you need a tool to get it off. A metal one works the best. There was a post in the last week or so about how hard some have had removing theirs.