Haha. Mine does not have that o ring, but Mine is also no longer for sale, I m going to use it.
P.s. mine is shiny :-)
This is a good deal for a 15mm, mine was only a 14.
You could let use know the atomizer size and if it comes with a jet.
Also. Show us this O-ring! Pull it out. I wanna see what I m missing. I have never heard of it.
If its a standard o ring and not a special one it would move the carb out just enough to make the intake line up with the gap on the clamp and leak even more. . .