Hi, post up a picture of the linkage is it moving freely/properly set up??? when i stripped all mne down and put back had the same problem but with slight ajustment and care all worked smoothly is it both carbs racing off or just one side being held open??? What linkage are you using mine is a bell crank and not the prettiest of affairs, but have no room for hex bar type....if you are using hex bar does it all move freely before connectiong throttle cable???