Winterizing Boat Engines: Steps To Take For Safe Storage

Winterizing a boat engine is essential to prevent damage from freezing temperatures. The process involves several steps, including flushing and draining water lines, replacing engine oil and fluids, protecting internal engine components, and more. The specific steps may vary depending on the type of boat engine and it is important to refer to the manufacturer's instructions or seek professional help if needed. One crucial aspect is to prevent water inside the engine, as it can freeze and crack the engine block, resulting in costly repairs. Additionally, fuel stabilizers and biocides are used to prevent issues caused by fuel deterioration. Proper winterization ensures the boat engine is protected during the off-season and helps extend its lifespan.

Winterizing a Boat Engine

Drain water from the engine

To prevent water in your boat engine from freezing and cracking the block, it is essential to drain the water from the engine. This process can be done in several ways, depending on the type of engine and the specific instructions provided by the manufacturer. Here is a detailed guide on how to drain water from a boat engine for winterizing:

Understand Your Engine Type:

Before beginning the winterizing process, it is crucial to identify the type of engine in your boat. The two common types are inboard and outboard engines. Inboard engines are typically found inside the boat, while outboard engines are mounted on the outside. Consult your owner's manual or a marine mechanic if you are unsure about your engine type.

Prepare the Engine:

Before draining the water, it is recommended to prepare the engine by flushing it with water muffs or running it in a tank of clean water until it reaches the optimum operating temperature. This step ensures that the engine is clean and any contaminants are removed. Additionally, if your engine has a fuel line, it is important to disconnect it from the engine while the engine is still running. This will prevent gums from forming in the stagnant gasoline and clogging lines, jets, or injectors.

Drain Water from the Engine:

The process of draining water from the engine will vary depending on the type of engine. For inboard engines, you may need to open petcocks or remove plugs to drain the water. Consult your engine manual to locate all the petcocks and open them for thorough draining. If water fails to drain freely, there might be a clog, and you may need to remove and clear the opening. Don't forget to drain other components such as the sea strainer, seacock body, and water lift muffler.

For outboard engines, it is essential to tilt the engine down completely to drain all the water from the cooling system. Leaving the engine in the down position ensures that water does not drain where it shouldn't. Additionally, covering the engine is recommended, but ensure adequate ventilation to prevent condensation buildup.

Use Antifreeze (Optional):

While draining the water is essential, some boat owners choose to take an extra step by using antifreeze to protect their engines. This is especially useful for inboard engines, where you can run antifreeze through the cooling system. Choose a non-toxic propylene glycol antifreeze and ensure it is adequate for your local weather conditions. Before adding antifreeze, consult your owner's manual and follow the manufacturer's recommendations.

Additional Tips:

• If your engine has a spark plug, remove it before draining the water to prevent water from entering the cylinder.
• After draining the water, it is a good idea to spray fogging oil or an anti-corrosive compound into the engine to protect the internal components during storage.
• Remember to clean and lubricate external parts, such as the propeller shaft, linkages, and control cables.
• If your boat has a fuel tank, consider draining it or filling it to 95% capacity to prevent condensation and phase separation.

Change the oil and oil filter

Changing the oil and oil filter is an essential step in winterizing a boat engine. This process helps to protect the engine from residual acids and moisture that can cause pitting and other damage to vital engine parts during the winter lay-up period. Here is a detailed guide on how to change the oil and oil filter:

Before changing the oil, it is recommended to run the engine for a few minutes. This serves two purposes: it lowers the oil's viscosity, making it easier to drain, and it helps the oil pick up impurities that may be present. After a brief run, shut off the engine and proceed to the next step.

The next step is to locate and place a container under the oil drain plug. This plug is usually found at the bottom of the engine, and by removing it, you will allow the used oil to drain out. Make sure to have a container large enough to catch all the draining oil and to properly dispose of it afterward. Once the oil has finished draining, reinstall the drain plug securely.

Now, it's time to locate and remove the old oil filter. The oil filter is responsible for trapping impurities in the oil, and it needs to be replaced periodically. Be sure to have a new oil filter of the correct type and size ready to install. Clean the mounting surface of the filter, and then install the new oil filter, making sure to tighten it according to the manufacturer's specifications.

After changing the oil and oil filter, it is good practice to check the engine's oil level to ensure it is at the correct mark. Add oil if necessary, but be careful not to overfill. Once you have confirmed the oil level is correct, you can move on to the final step.

Finally, restart the engine and let it run for about a minute. This step allows the fresh oil to circulate to all internal parts of the engine. While the engine is running, keep an eye on the new oil filter to ensure it is not leaking. A leaking oil filter can cause a mess and lead to potential damage, so it is important to address any leaks immediately.

By following these steps, you will help protect your boat engine from the harmful effects of residual acids and moisture during the winter. Remember to always consult your owner's manual and follow any specific recommendations provided by the manufacturer for your particular engine.

Protect internal engine components

Protecting the internal components of your boat engine during winter is crucial to prevent corrosion and ensure its proper functioning. Here are some detailed steps to achieve this:

Use Fogging Spray or Oil:

Fogging sprays or oils are essential for coating the internal engine components with an anti-corrosive compound. This protective layer helps prevent corrosion and scuffing of internal parts during storage. Apply the fogging spray generously to all internal surfaces, following the instructions on the product.

Remove and Store Valuable Electronics:

It is advisable to remove any valuable electronics, such as GPS devices or fish finders, from the boat for safe storage during the winter. This not only protects them from potential damage but also deters theft.

Insure Your Boat:

Even if your boat will be out of the water and inactive during winter, it is crucial to maintain insurance coverage. This provides peace of mind in case of any unforeseen incidents or damage that may occur while the boat is in storage.

Apply Anti-Corrosion Measures:

Use an anti-corrosion spray or mist-coat to protect the engine's external surfaces and other unpainted parts. This extra layer of protection helps prevent corrosion and ensures that your engine remains in good condition during the winter months.

Lubricate Linkages and Mechanisms:

Pay special attention to lubricating all moving parts, linkages, and mechanisms, such as the electric starter drive mechanism. Refer to your owner's manual for specific recommendations on the type and amount of lubricant to use.

Drain and Refill the Gearcase:

It is important to drain and refill the gearcase with the lubricant specified in your owner's manual. This helps prevent condensation from forming inside the gearcase, reducing the risk of corrosion and ensuring smooth operation.

Touch Up Damaged Paint:

Inspect the engine for any damaged paint or coating. Apply an anti-corrosion spray or touch-up paint to these areas to prevent further deterioration and protect the engine from the elements.

Clean and Lubricate the Propeller Shaft:

Take advantage of the off-season to thoroughly clean and lubricate the propeller shaft. This maintenance step helps prevent corrosion and ensures optimal performance when you return to the water in the spring.

Remember, it is essential to follow the manufacturer's instructions in your owner's manual for engine winterization. These steps will help protect the internal components of your boat engine, ensuring its longevity and reliable performance for the upcoming boating season.

Flush and drain water lines

Flushing and draining the water lines is an essential step in winterizing a boat engine. Water expands under extremely low winter temperatures, which can cause damage to the engine. Therefore, it is crucial to flush and drain water from the engine cooling systems, plumbing system, or any other system holding water.

To flush the engine, use water muffs until the engine reaches its optimum operating temperature. This will ensure that the engine is free of any salt deposits and that all water lines are clear. It is also important to check your engine manual for the location of all petcocks and open them to allow for thorough drainage. If water fails to drain freely, the petcock may be clogged, and you may need to remove and clear the opening with a tool or coat hanger.

For raw-water-cooled engines, you will need to close the intake seacock and remove the intake hose. Submerge the end of the hose in a bucket of environmentally safe antifreeze and run the engine until the antifreeze comes out of the exhaust ports. This will ensure that the antifreeze reaches all parts of the cooling system, preventing freeze damage.

For freshwater-cooled engines, it is important to check the coolant mixture and ensure it meets the manufacturer's recommendations for your locality, typically a 50/50 mix with water. If the coolant is rusty or dirty, it should be drained and replaced. You can then either drain the system and leave it dry or fill it with winterizing antifreeze (propylene glycol).

Don't forget to also drain other systems that hold water, such as sinks, tanks, heads, raw water washdowns, livewells, and the bilge pump. Open all faucets and let them run until the freshwater tank is dry. Then, close the faucets and add antifreeze to the tank. Start with the faucet farthest from the tank and work your way closer, ensuring that antifreeze comes out of each faucet.

By thoroughly flushing and draining the water lines and following the other necessary steps for winterizing your boat engine, you can help prevent freeze damage and ensure that your boat is protected during the winter months.

Change the fuel filter

Changing the fuel filter is a crucial step in winterizing your boat engine. It is a relatively simple process but can get messy, so it is recommended to place oil-absorbent pads underneath the filters to capture any spills.

Firstly, turn off the fuel petcock (if your boat has one) to prevent fuel from draining out of the tank. Then, place a suitable receptacle under the primary filter to collect any spilled fuel.

The next step is to unscrew the T-handle on top of the filter and remove the cap. The type of filter you have will determine the exact steps to take here. For example, if you have a Parker Racor filter, simply unscrew the T-handle and remove the cap. If you have a different type of filter, refer to the manufacturer's instructions, which are often contained within the box that the new filter comes in.

Once the cap is removed, lift out the old filter element and place it into a plastic bag for proper disposal. Be sure to open the petcock on the bottom of the filter to remove any water and dirt that has accumulated. This step is important as it helps prevent engine breakdowns caused by dirty fuel.

Now it's time to remove and dispose of the rubber O-ring from the base of the threads on the T-handle. Use a thin-blade screwdriver to carefully pry out the rubber gasket from the groove on the underside of the lid. Clean the mating surfaces and seal groove with a clean, lint-free rag.

The next step is to drop the new filter into the housing and fill it with fresh, clean fuel. Smear some of this clean fuel onto the surfaces of the new gasket and O-rings before carefully reseating them into their respective grooves.

Finally, replace the cap, making sure the filter housing is correctly seated in the groove. Screw down the T-handle, complete with a new O-ring, tightening it by hand only.

For secondary filters, which are usually mounted on the engine close to the lift pump, the process is similar. Remove the bottom bowl and drop out the old filter, being prepared for potential fuel spills. Remove the O-ring seals from the grooves, wipe the seating surfaces with clean paper towels, and install new O-ring gaskets after smearing them with fresh, clean fuel. Mount the new filter and screw the assembly together, being careful not to overtighten the bolts.

After changing the fuel filters, it is important to bleed air from the fuel system. Consult your engine manual for specific instructions on how to do this, as the process may vary depending on the type of engine you have.

Frequently asked questions