How Do You Winterize A Boat Motor?

I am a new boat owner and I'd like to be able to handle the maintenance on my own rather than depend on someone else when it comes to seasonal winterizing. How do you winterize a boat motor? I have a couple weeks to figure it out so I am reaching out for any help or advice. Thanks Dock Line forum in advance. If it matters, I have Mercury 250 pro



  • Winterizing a boat motor is actually pretty easy. My father taught me how to winterize a 4 stroke motor on our Zodiak when I was guiding in Alaska. There are probably many articles out there that can explain it better than I can but I'm happy to pass my knowledge along. I think this depends on the type of motor and what systems your boat has on board but the goal here is the same. We want to keep things from freezing and we want to keep fuel and fuel lines fresh for next season. The first thing I do is fill the tank of gas to about 90%. This allows for fuel expansion and minimizes any condensation. Then we add a fuel stabilizer, proportionately, to the fuel left in the tank. Run the motor with fresh water through earmuffs for about 5-10 minutes. Enough to let it warm up and get the fuel through the lines. The next step is to winterize the water cooled outboard. You attach the boat winterization kit to the earmuffs, start the motor and open the valve allowing the antifreeze to course its way through the motor while flushing out the fresh water. Once you see pink fluid coming from your spitter, you'll know all lines, ports and holes that could contain water in the motor are now filled with antifreeze. We disconnect the battery and store everything in the shed. Your motor is much nicer but the same concepts will travel over. We would always make sure to store the outboard flat or in the down position as well. I'm not entirely sure what this benefits but its just something that stuck with me. Best of luck @NorthernExplorer82

Sign In or Register to comment.