To winterize the engine with antifreeze, you’ll need a five-gallon bucket, and enough antifreeze for your engine and related plumbing (at least two gallons). If your engine takes a lot of antifreeze, you might also need a helper to add antifreeze to the bucket as needed.Click to see full answer. Correspondingly, how much gas should I put in my boat over the winter?About a month before you stop boating for the season (or at the very least the last time you fill up before your last boating trip) start using a fuel stabilizer. Before you put your boat away for the winter, fill the tank about 90-95% and be sure to add the appropriate amount of fuel stabilizer.Also, how long does it take to winterize a boat? It takes me about 4 hours to winterize. That’s draining the ballast system and blowing out all the lines for the heater and shower plus all the engine stuff like oil change and filling with coolant. The wash and wax are done by a friend before it goes away and then just a cover. Also Know, what happens if you don’t winterize your boat? If You Don’t Winterize Your Boat, Here’s What Happens. Water freezes and expands and can damage anything it’s trapped inside. Water may seep into unprotected spaces to do this. Acidic and corrosive wastes, salt and corrosion buildup can damage delicate parts in engines.Should I leave gas in my boat over winter?Experts in the fuel industry now recommend storing the tank at 90 percent of its capacity (the safe fill level) to minimize the potential for condensation and to allow for expansion. In addition to a nearly full tank, it is also highly recommended that a stabilizer be added to the fuel prior to prolonged storage.