Hi, I'm new here and this is my first post.
I bought a FLU419 a few weeks ago, and it has been quite an adventure in learning about these and fixing the issues I've found with it so far. I'm an aerospace guy so it's in my wheel house. I think I got lucky, it has the "Overhauled at RRAD" plates (2009), and only 53 hours on the engine since that. Seems like a really clean one.
This is not a troubleshooting thread, as I have already found and fixed the source of my fuel system problem. On mine, the main air leak was a missing crush washer on the banjo fitting at the fuel inlet to the lift pump. I also had to replace the hand pump primer thing, fuel filters, the gasket at the strainer, and all the fuel lines.
My question is, what is this unlabeled part above the fuel filter housing? I can't seem to find any information as to what it is or what it does. See attachment.