It is ok to unhook the throttle return spring, buuuuuut don't take it off because the spring tho unhooked will keep pressure on the throttle arm and keep it from vibrating as mentioned.
ORIGINAL: RCIGN1
The carbs are made for weedeaters and chainsaws..The spring is to keep the engine at idle until the trigger is pulled for more rpm...It also keeps the throttle disc centered in the bore..Without the spring the disc vibrates against the sides and wears out both the disc and the carb body...Enough wear and the carb won't shut off at idle....