I took off the spring that comes inside of a Walbro carb, to avoid tension to the servo, but now the barrel do not actuates correctly.

I actually have to replace a spring ( but don´t know how to separate the plastic parts to position a new spring) inside the barrel of the walbro carb. or order the entire part with spring already installed.
it seems to be the WYL K-20, "160A-218 pinted on, do you know were to get a exploded view of the carb and were to order the part or entire carb??
Thanks