I got some really unpleasant throat burn from my 510 also. I inspected the atomizer really closely and found some synthetic fibers stuck under the metal 'wick' part (is that called the bridge?) I had a helluva time getting them out, and was a little concerned about doing so, afraid I might ruin the atomizer. But sure enough, these fibers were burnt.
I thought these fibers might be polyfill from the carts, but nope - it's definitely not the same material. Looks like the same stuff as what they make cheap nylon rope or twine from.
Anybody else seen this material? Is it even necessary for the atty to function correctly? I took it out of mine, and it seems to work OK...
yeah, that is the wick from the atomizer bridge to the nichrome coil... you kind of need that part. It gets burnt from running your atty too dry