Here's another solution:
http://www.prme.nl/forum/viewtopic.php?t=97
The pring can be removed if the arm butts up well against the carb body. Or it can be fitted on the opposite side.
The brass lever can be bent and twisted to suit the application.
I like to have the spring in place, and apply a pull force when opening the throttle. Absolutely slop-free operation. The servo is set up to have a larger throw for the second half to full throttle whilst never touching the full open stop, and a reduced throw for idle to half throttle. That makes the engine response more linear.