So is this my carb?
Alright I called JD Jetting. They had two thoughts: one is the PO installed a bigger pilot jet, thinking that was solving an issue. I shouldn't run anything bigger than a 42, 40 is stock, they suggest a 42. So I ordered one. The fuel screw washer comes in a kit - spring, washer and 0-ring for $8.95. So I ordered one (could use a new o-ring anyway) once it gets in, I bet I can take some measurements and find a box of them at MSC or something.
Second thought was the slide in the carb, and the fact that a lot of people install the plate on it backwards. The correct way is with the hole towards the brass pin, even though intuitively it looks like it goes the other way because of how it's shaped. They say if you install it backwards, your bike runs terrible at idle and doesn't start well. An enormous picture can be found here: http://www.pbase.com/jdjetting1/image/53264343
I should have the new washer and pilot jet later in the week..