Hi Norm, I did not know you were using new primer caps and new floats , I would not think you are having any flooding issues,unless the needles are too heavy for the float , If the needle is sticking closed ,I would try tying the bottom of the needle with some fuse wire to the float.
If there is not enough room for fuse wire at the bottom of the needle I would drill a small hole in the bottom centre of the needle and loctite the wire in then drill a small hole for the wire to go through the plastic float.
If I was having the problems you are having I would experiment with making some needles out of alloy welding rod.
Just a few ideas but it sounds like it's a frustrating problem getting the needle and seat to be reliable 100 percent of the time.
