Hey Mose,
There is no filter, but there is a pick up tube. �It is basically shaped like an upside down 'U'. �If you're sticking a stiff wire up in there, the sharp turn of the 'U' may be impairing your wire. �Try a light gauge wire and see if you can get it to bend, and go all the way through the 'U'.
The other thing you might try is compressed air. �Shoot compressed air through the fuel line port. �Then feel if you have air coming out of the filler neck. �If you feel air, the pick up tube is not clogged. �If you don't, you may have to get a little aggressive with your wire. �The pick up tube is sodered in. �It's pretty tough, but you can damage it if you're not careful.
Come back and tell us what you did and if it worked. �
Good Luck!
Edit::: By the way, that's a nice looking 3A. Intoduce yourself in the "Once you've joined" section and post more photos. We all like lot's of photos.
Tim