Air Vent System
An air vent solenoid is installed on the carburetor on all models, except the RX-3SP. The purpose of this system is to prevent carburetor bowl evaporated fuel from collecting in the intake manifold after a hot engine is shut off. See Fig 1. When the ignition is turned off, the solenoid closes an air vent in the carbon canister, effectively trapping the evaporated fuel.