LT 400 z quad won't run unless choked
 

Hello all,

I have an 03 Suzuki LT400Z quad that was running PERFECT last time I rode it last summer. I let her sit all winter and now when I start her, she runs great
in choke (idles and revs) but dies immediately when turning the choke off.

I have...

1) taken the carb apart (it looked very, very clean inside) and cleaned everything just to be sure.
2) put it back together and it still does the same thing.

3) I then took the carb apart again and REALLY went through every part, making sure everything was clean and in excellent condition.
4) I also took the petcock valve off and cleaned the screen (it too was very clean) and made sure fuel flow was good.
5) put everything back together and it still does the same thing.

6) installed a new NGK CR7E plug and still does the same thing
7) reseated the carb seals and tightened very tight to make sure no air was leaking...

Still, won't run off choke...

It's seems odd that it ran PERFECT before sitting, and now mysteriously won't run unless choked.

What should I do next? I want to sell it but need to get it running perfect first...