When I first got my 510*Yeti* one atomizer work perfect. no funny taste and a tons of vapors. One didn't produce much vapor as other and end up with funny smell that didn't go away end up opening up and see what inside.
Figure I order a few more to keep back up, both of them taste like crap!
Taste very metallic and can't healthy.
I have 6 510 atomizers that I've used at least a couple of times each, some more than others, and I'm pretty sure all of them have had that awful taste at one point or another, assuming it's the same as what you're describing (electrical fire? Burnt metal and plastic?). I've been able to get them all back to more or less normal either by dripping a couple of drops into the atomizer mesh and waiting a couple of minutes before starting back in with a fresh cart, or by blowing them out, dripping in a couple of drops, and letting them stand overnight with the mesh side up. Sometimes it takes a couple of hits to clear the taste.
My operating theory at this point is that if the inner wick material is allowed to get too dry, it will give off those fumes as it burns from the heat of the atomizer. Must keep these atomizers nice and moist!
EDIT: Forgot to mention that I had one atomizer that was particularly awful out of the box, which I returned for another. The inner wick material was sticking almost all the way out from under the mesh bridge, and it ran super-hot as well as stinky.
I noticed that my atomizers fit kind of loose even when tightened all the way. Like they can be wiggled into place.. anyone else notice that?
Most of my connections seem off, if you look at the assembled 510 from the side it looks bent at the connector, and I can wiggle the ends back and forth, even when they seem naturally tight. I've seen others report this as well. Every now and then I try to screw the parts together as tightly as I can, but it always feels like overtightening and I'm afraid it's bad for the connections.
So, I have learned to live with crooked e-cigs, because I enjoy the 510 so much, even with this and the nasty fumes issue.
Tim