Hey, I think that's a pic of my motor! Autograph signing after work!
Lampo,
I assume you have a throttle wire, not a cable? Maybe it is too lubricated in the housing? Maybe your return spring is too firm?
Here's another couple pics of the hookup. Once you click on it, hit the "next" button to see a couple more pics:
http://rides.webshots.com/photo/1130825413050768402MNkigr