Re: 1990 rude E3BRESR needle valve won't seat
It's possible you don't know how it feels when the needle seats (been there), and are afraid of forcing it (been there too -- and do need to take some care). I'd suggest that you get the packing out if it hasn't come out with the needle, and try gently seating it without packing. There is a metal to metal feel. If there is anything in there, use a flashlight and a small long screwdriver, or something similar to carefully clear it out. (flashlight helps.)
edit: It is possible that the tip of another needle is broken off in there, and blocking insertion of the current needle. unlikely, but possible. With a flashlight, you should be able to see the tiny opening where the needle seats
