I see you already have an answer but here goes anyway. From the picture it looks like you have a 2005 Sauron/U. These are both drain hoses. That's a plug in the hose, not an electrical connection. The other end is attached to the carb float chamber. Remove the plug to drain the hose. Emissions requirements does not allow the manufacturer to leave the hose open to the atmosphere. The air intake you have circled in the picture provides air only to the clutch and belt for cooling. Regarding the battery, the security system can drain the battery over time. If you live where it freezes during the winter and the battery was completely dead, then it may have frozen and will not be able to take a charge. These scooters need a Battery-Minder or Battery Tender during storage to prevent complete discharge, as no easy method is provided to disable the remote start / security system.