Hey guys just boat a 1993 Smoker Craft Alaskan Pro 15' boat. Previous owner said he does not know what this white tank is for? Any ideas??? It has a 40 HP Mercury 2 stroke oil injected which the oil goes into the motor, has an Evinrude 4 hp kicker 2 stroke that gets its oil pre mixed into its gas tank. The hose goes down under the deck of the boat and have no idea where it could be going.