@jfb05177 posted:there are torsional (mouse trap) springs on both primary and secondary plates.
the shop did NOT install a throttle return on mine at all.
I have a problem with idle being erratic. I just noticed the secondary is sticking!!!! there is a youtube showing the recentering the secondary plates (by loosing screws to shaft and retighting). I don't want to go that far (yet) and plans today is to add an extension spring to the secondary, maybe another to cable.
I would send the unit to a dealer and let them take care of the issue….