I'm a new boat owner, I have a old Bass Tracker III (81), with a Merc 40 HP 2 stroke, I have Two new batteries and an on board charger (Minn Kota). Do I need to remove batteries? I keep the boat tilted up so no water will stand in boat, I also keep it covered. I put new grease in lower unit. cranked motor with kill switch off until no water came out sight hole. and I removed transom saver so motor is in full upright position. I put sta-bil in fuel tank and have it half way full. Is there something else I need to do before 20 something degree next week???? Thanks for help