Q: What is the purpose of this system and how to check and replace Purge Valve and Canister on Mercury Cougar?
A: This system prevents hydrocarbons from polluting the atmosphere by storing fuel vapor from the tank. It includes a charcoal canister, purge control solenoid, connecting lines, fuel cap, and fuel injection system. Vapor from the tank is stored in a charcoal canister located near the front wheel well until the engine starts. The canister connects to a purge solenoid, which opens at engine start to draw vapor into the air cleaner. The canister and solenoid should be checked for damage or malfunction and replaced if necessary. To replace the canister, remove the mounting bolt, lower the canister, detach the hose, and remove the canister. For other components, use the VECI label schematic to locate and replace them. Installation is the reverse of removal.