It might be a canister for a different year vehicle. Mine has the "purge" port fused solid. I think it may be from an 89 Jeep or something. I put a canister purge valve, something like this
http://www.autozone.com/emission-co...canister-purge-valve/68752_0_0/?checkfit=true
on mine where the smaller line (valve) goes to a ported vacuum source on the carb and the bigger lines connect the canister output to the carb. That way the carb only pulls fumes when there is a vacuum on the ported line.
Or, it could be stock and you have a different system...
