The engine idles fine on full choke. When I push the choke down it dies after 3 seconds. I got some starting fluid and as the bike was idling at full choke I sprayed a little on where the carburetor meets the cylinder. It immediately died. When I spray wd-40 on it and flick the choke lever down it runs fine. I can pick up the back tire and throttle it and it sounds great. Once the wd-40 has run off it shuts off. What's happening.http://motorbicycling.com/images/smilies/Waa.gif