How To Winterize A Boat – Step By Step Guide

Winterizing your boat does not have to be complicated or time-consuming; with the proper materials and maintenance tips, you can get through the process in no time. 

In this article, we will provide some essential tips on how to winterize your boat correctly so that it lasts year after year.

What Does It Mean To Winterize A Boat?

Winterizing a boat involves taking steps to protect the boat and its systems from cold weather and potentially freezing temperatures.  Here are some potential consequences of not preparing your boat for the Winter:

• Water in the plumbing and engine can freeze, causing pipes to burst and other damage.
• The battery can lose its charge and fail to start the boat in the spring.
• The exterior of the boat can become damaged by wind, snow, and ice.
• The upholstery and other materials can become moldy or mildewed due to exposure to moisture.
• The boat may not be ready for use when the weather warms up again, resulting in lost time on the water.

10 Steps For Winterizing Your Boat:

• Step 1: Supplies you will need
• Step 2: Flushing and Draining Your Engines
• Step 3: Winterize the Water System
•  Step 4: Stabilize Your Fuel
• Step 5: Change Engine Oil
• Step 6: “Fogging Your Engine”
• Step 7:  Replacing Gear Oils
• Step 8: Lubrication
• Step 9: Protect against theft
• Step 10: Covering your Boat

Can I Winterize My Boat By Myself?

Yes, you can Winterize your boat yourself, which will undoubtedly save you a good amount of money. Still, for those who are unsure of themselves or simply out of town, the professional option is always available.  

Remember: As with any task that you weigh using a professional service vs. “Do it yourself”- Not correctly winterizing your boat could very well end up in you spending more money than it would have cost to just have the professional do it in the first place!

How Much Does It Cost To Winterize A boat Yourself?

To Winterize a boat yourself would cost somewhere around $200 to $250.  Should you choose to hire a professional, look to spend around $500 to winterize your boat.

Winterize Your Boat Step 1 (Supplies needed):

To Successfully Winterize your boat this year, you will need some (or all) of the supplies below (Depending on if you wish to cover every step or only take a few):

• Engine oil
• Gear oil
• Grease/Marine Lubricant
• Motor Flush Engine “Ear Muffs”
• Fuel Stabilizer
• AntiFreeze
• Boat cover
• Boat Cleaner/Soap

Winterizing Your Boat Step 2: Flushing & Draining Your Engine(s)

Flushing your boat’s engine involves running clean water through the engine to remove dirt, debris, salt, and other contaminants that can build up over time and damage the motor. Here are 6 general steps you can follow to properly flush a boat engine before Winter (Or any time):

1. Prepare the boat: Make sure the boat is in a stable position and the engine is turned off. 
2. Connect the flushing hose: Attach a flushing hose to the engine’s flushing port or raw water intake. The flushing port is typically located near the bottom of the engine and is used to introduce clean water into the engine.
3. Turn on the water: Turn on the water supply and allow the water to flow through the engine for a few minutes. This will help to remove dirt and debris from the engine’s cooling system. Tip: Get the engine warm/hot to help loosen up more debris.  Warning For Boats On Land: Do not run your engine without running water
4. Check the water flow: Observe the water flow from the engine’s exhaust to ensure that it is clear and free of debris. If the water flow is dirty or obstructed, allow the water to run for a few more minutes until it is clear.
5. Turn off the water: When the water flow is clear, turn off the water supply and disconnect the flushing hose.
6. Dry the engine: Use a towel or chamois cloth to dry the exterior of the engine. This will help to prevent rust and corrosion.

By following these steps, you can effectively flush your boat engine and make sure that it is ready when Spring comes around.

Winterizing Your Boat Step 3: Drain Your Water Systems

Again, winterizing anything that holds water will be of the utmost importance, as freezing water will expand and break anything that cannot expand with it, such as hoses and pipes.

Drain all freshwater plumbing systems such as heads, sinks, and tanks before pumping antifreeze into them to protect them from freezing temperatures.   

Use the “Pink” anti-freeze you find in Marine and RV Stores because this is the anti-freeze that is safe for drinking systems!

Tip: Additionally, you should also drain any other internal systems like the bilge and raw water washdown.  

How To Flush Your Freshwater System: 

1. Turn on The Freshwater Pump: Activate the Freshwater pump so the system has pressure.
2. Drain the freshwater lines: Turn on every faucet (Hot and cold), nozzle, and hose the boat has until they start to spit water with some air, then turn them off just before they stop completely. Don’t run them until the tank is dry, or your pump might have a problem picking up the antifreeze.
3. Flush the head: Flush any remaining water in your head until the bowl is dry.
4. Drain Hot Water Heater: If you have a hot water heater, there should be a valve that you can open to drain the tank. This water should flow into the back bilge and pump out of the boat.
5. Add antifreeze: Find your water fill and start pouring in the anti-freeze until you have enough antifreeze to supply your entire system, then close your water fill. If you have a water heater, you will need to add enough anti freeze to fill the heater AND the rest of the system.
6. Run the Anti Freeze through the system: Run every faucet, nozzle, and hose until you see ONLY the pink anti freeze, then turn it off. Additionally, don’t forget to flush the heads until you see pink fluid on the bowl.
7. Shower Drain: If you have a shower drain, pour anti freeze down the drain until you hear the bilge pump turn on.

Winterizing Your Boat Step 4: Stabilize Your Fuel

Using a high quality Fuel Stabilizer is an essential step in maintaining the health of a boat’s engine and preserving your fuel supply while in storage.

Fact:  Fuel can deteriorate in as little as 60 days

There are several steps you can take to stabilize fuel in a boat for winter:

1. Run the engine: Before adding the fuel stabilizer or new fuel, run the engine for a few minutes to help circulate the old fuel and remove any water or contaminants that may be present.
2. Add a fuel stabilizer: Fuel stabilizers are chemical additives that help to prevent fuel from degrading over time. They work partly as an antioxidant and partly by absorbing water before the fuel can.  Fuel can be stabilized for up to 2 years.
3. Add Fresh Fuel:  Put fresh fuel into your boat after adding the stabilizer to help it mix better. Do not top off!  Leave some room for expansion (Approx 90% is good).
4. Run the engine again: After adding the fuel and stabilizer, run the engine for a few more minutes to help circulate the treated fuel throughout the system.

• Tip: Use a Quality Marine Fuel Stabilizer such as STA-BIL 360 Marine to ensure you are getting the best possible treatment

Fuel Stabilizer FAQ:

Should I keep my gas tank full in the Winter? 

No, you should add fresh fuel, but you should always leave some room in the tank for expansion.

At what temperature does gas freeze?

For pure gasoline to freeze, it usually needs to reach a temperature between -40 degrees and -200 degrees; however, most companies that deliver gasoline will mix in additives to prevent freezing, so the exact freezing point of gasoline will vary.

Why shouldn’t you let your gas tank run low in the winter?

It is not recommended to let your gas tank run low in the winter for a couple of reasons:

1. Cold temperatures can cause condensation to form in the fuel tank, which can lead to water in the fuel. If the fuel tank is low, there is less fuel to dilute the water, which can cause engine problems.
2. Running the gas tank low can also cause the fuel pump to pick up debris from the bottom of the tank, which can clog the fuel filter and cause engine problems.

Winterizing Your Boat Step 5: Replace Engine Oil

Changing engine oil is an important part of boat maintenance and boat winterization. Old oil can contain contaminants like acids and moisture that will cause damage while storing your boat for long durations.

Here are the general steps you can follow to change the engine oil in a boat:

1. Gather the supplies: You need a new oil filter, an oil drain pan, and the appropriate oil for your boat’s engine. Consult the owner’s manual or the manufacturer’s website to determine the correct type of oil to use, but ALWAYS use “Marine” supplies because they are specially formulated for boat engines.
2. Warm up the engine: Start the engine and let it run for a few minutes to warm up the oil. This will help to loosen any dirt or debris that may be present in the oil.
3. Locate the oil filter and drain plug: Consult the owner’s manual or the manufacturer’s website to locate the oil filter and drain plug on your boat’s engine. The oil filter is typically located near the top of the engine, while the drain plug is usually located near the bottom.
4. Remove the oil filter: Use an oil filter wrench to loosen and remove the oil filter. Be careful not to spill any oil as you remove the filter.
5. Drain the oil: Place the drain pan under the drain plug and use a wrench to loosen and remove the drain plug. Allow the oil to drain completely from the engine.
6. Replace the oil filter: Install the new oil filter by hand, making sure to tighten it securely. Consult the owner’s manual or the manufacturer’s website for the correct torque specifications.
7. Add new oil: Consult the owner’s manual or the manufacturer’s website to determine the correct amount of oil to use in your engine. Pour the oil into the engine through the oil fill hole, making sure not to overfill.
8. Check the oil level: Use the dipstick to check the oil level and add more oil as needed. Consult the owner’s manual or the manufacturer’s website for the correct oil level.

Winterizing Your Boat Step 6: Fogging A Boat Engine

Fogging a boat engine is a process that helps protect the engine ahead of winter storage. The idea behind fogging is to coat the internal parts of the engine with a special type of oil called fogging oil. This oil helps to prevent rust, reduce moisture buildup, and keep the internal parts lubricated.

Here’s how you can fog your boat engine in simple steps:

1. Find the air intake: The air intake is where air enters the engine block and is usually near the carburetor or throttle body.
2. Remove the air filter: You’ll need to remove the air filter so you can access the air intake.
3. Spray the fogging oil: With the engine running, spray the canister of fogging oil into the engine’s air intake(s) per the instructions on the brand of fogging oil you purchase. (See the next bullet point first)
4. Let the engine cut out: Spray fogging oil in quick spurts first (It is ok to see white smoke). The engine will want to cut out, and when it does, stop spraying the oil and allow it to recover. After about 20 seconds (or so) of this, start spraying the fogging solution lubricant directly into every intake pretty steady until the engine cuts out.
5. Spray the Combustion Chamber: (With the engine off but at a normal operating temperature). Remove the spark plugs and spray the fogging oil directly into each opening.

Tip: Be careful when fogging your boat’s engine. Read the manual or google instructions for fogging your specific engine and make sure you’re using the right amount of fogging oil.

Winterizing Your Boat Step 7: Replace Lower Unit Gear Oil

Replacing the lower unit oil is as important as replacing the engine oil during boat winterization. The lower unit contains metal gears that turn the props, and these gears need to be protected.

Here’s how you can change the lower unit oil:

1. Locate the drain plugs: There are two drain plugs on an outboard motor lower unit, one at the top of the lower unit and one at the very bottom.
2. Remove the drain plugs: Use a wrench to remove the drain plug at the bottom first so that you can control the flow; then, remove the top drain plug and allow all of the oil to drain out completely.
3. Pump the new oil in: To fill the lower unit with new oil, you will need to use a pump that injects the oil into the lower unit. This pump will usually screw on to the top of a quart of oil and have a tube that screws into the bottom drain plug hole.
4. Top off the oil: Pump the new oil into the lower unit until the oil starts coming out of the top drain plug hole, then replace the top drain plug while keeping the pump attached to the bottom plug hole.
5. Finish Up: The final step is to remove the pump hose from the bottom drain plug hole and QUICKLY reinsert the bottom drain plug.

Tip: Make sure you use the right type of oil for your lower unit and follow the manufacturer’s recommendations for the amount of oil to use should it require a certain level.