Preventing Engine Block Freeze: Tips For Boat Owners

Boat engines are vulnerable to freezing, which can cause severe damage. This is because the water inside the engine expands when it freezes, and this expansion can crack the engine block. To prevent this, it is important to winterize your boat by draining the engine of water and adding antifreeze. Other methods to prevent a boat engine from freezing include storing your boat in a covered area, using a heated engine cover, and stabilising the boat fuel.

Remove the boat engine from the water

Removing your boat from the water is a crucial step in winterizing it and preventing engine damage from freezing temperatures. Here are the detailed steps to guide you through the process:

Prepare the Boat

Before you arrive at the boat launch, ensure that your boat is ready for retrieval. This includes removing all tie-downs, except the winch line, and loading any additional supplies and equipment. Don't forget to insert the drain plug, disconnect the trailer's brake lights, and remove the motor travel supports if used. By preparing your boat in advance, you can avoid causing unnecessary delays for other boaters at the launch area.

Position Your Vehicle and Trailer

Back your trailer into the water until about two-thirds of its bunks or rollers are submerged. It is recommended to keep the towing vehicle's wheels out of the water if possible. Ensure that you apply the parking brake on your towing vehicle.

Attach a Bow Line

For added stability during the retrieval process, attach a bow line to the boat. This is especially helpful if you are launching the boat alone. If there are two people, and one remains in the boat, a bow line may not be necessary.

Maneuver the Boat

Carefully drive your boat towards the trailer and attach the winch line. Once the winch line is securely attached, shut off the engine and tilt the engine up. This will make it easier to pull the boat onto the trailer.

Pull the Boat Out of the Water

Crank the winch line to pull the boat up the trailer. Ensure you stay clear of the direct path of the winch line for safety. Once the boat is securely on the trailer, tow your trailer out of the water and away from the boat ramp.

Post-Retrieval Steps

After you've successfully retrieved your boat, there are a few important steps to complete. Remove the drain plug and pump out or drain any water from the bilge and live-wells or bait-wells if applicable. Clean your boat, removing all plant materials to prevent the spread of aquatic species. Additionally, unload any extra fuel and equipment away from the ramp to avoid causing delays for other boaters.

By following these steps, you can effectively remove your boat engine from the water, which is an essential part of winterizing your boat and preventing engine damage caused by freezing temperatures.

Drain the boat motor of all water

Draining the boat motor of all water is a crucial step in preventing freeze damage to your boat engine. This process is slightly different for outboard and inboard motors, so make sure you know which type of motor you have before beginning.

For an outboard motor, follow these steps:

• Place your boat on a trailer and secure it properly.
• Trim the outboard motor to its maximum angle, typically around 65 degrees.
• Let all the trapped water drain out.
• Use a sponge to wipe down the engine, engine bay, and any flat horizontal surfaces to remove any remaining water.

If you have an inboard motor, the process is a bit more involved:

• Move your boat to a flat area where you can work on it.
• Drain the water from the engine and engine bay.
• Change the gear lube oil to ensure there is no water in the gear lube tank that could freeze.
• Follow the engine manufacturer's instructions for draining the engine, as this may vary depending on the specific make and model of your boat.

Remember that it is essential to remove all water from the boat motor to prevent freeze damage. Even a small amount of remaining water can freeze and cause cracks in the engine.

Stabilise the fuel

To stabilise the fuel, you should start by filling the fuel tank with fresh fuel until it's 99% full. Leave just enough space to put the fuel stabiliser in the tank. Next, pour the fuel stabiliser into the tank. One ounce of stabiliser treats 2.5 gallons of fuel. Then, start the boat motor and let it run idle at approximately 1,000 RPM for five minutes until the stabiliser mixes into the entire fuel system. Finally, turn off the boat motor. This process will prevent the fuel from oxidising and forming a pasty, gum-like substance in the fuel tank and fuel lines. It also prevents corrosion of the fuel tank.

Change the gear lube oil

Changing the gear lube oil is an important step in preventing your boat's engine from freezing. This process should be done at the end of the boating season and ideally before temperatures drop to 32°F (0°C) or lower. Here is a step-by-step guide on how to change the gear lube oil:

Step 1: Prepare the Work Area

Start by placing a large piece of cardboard under the motor to catch any drips or leaks. Place an oil pan on top of the cardboard to collect the used gear lube oil.

Step 2: Loosen the Plugs

Locate the bottom and top plug on the gear lube tank, which is typically found in the lower unit of the motor near the propeller. Some motor models may have two upper vent plugs. Loosen these plugs but do not remove them yet.

Step 3: Drain the Old Gear Lube Oil

Trim the motor down into the catch pan and ensure it is level so that gravity can assist with the draining process. Remove the plugs, starting with the bottom one and working your way up. Allow the old gear lube oil to drain completely. This may take a few minutes.

Step 4: Inspect the Plugs and Oil

While waiting for the oil to drain, inspect the plugs for any metal shavings. Magnetic plugs are designed to collect these shavings. Also, check the oil for any signs of water contamination. If the oil has a milky consistency, it indicates that water has entered the gear lube tank. If you notice any issues, it is best to consult a dealer or mechanic for further diagnostics and repairs.

Step 5: Pump in the New Gear Lube Oil

Once the draining slows to a very slow drip, it's time to fill the gear lube tank with fresh oil. Attach a gear lube pump to the lower screw hole and begin pumping in the new oil. It is important to fill the tank from the bottom up to avoid trapping air inside the components. Continue pumping until a small amount of oil drips from the upper vent plug, ensuring that the tank is topped off.

Step 6: Secure the Plugs and Clean Up

Replace the plugs, starting with the top one to create a small vacuum. Be quick when removing the pump and replacing the bottom plug to minimise oil leakage. Clean up the work area by disposing of the used oil, cardboard, and rags in an environmentally responsible manner.

Changing the gear lube oil is a crucial step in winterizing your boat's engine and preventing freezing-related damage. By following these steps, you can help ensure that your boat's engine remains in good condition during the cold winter months.

Spray carburetor inlets and spark plug holes

Spraying the carburetor inlets and spark plug holes is an important step in preventing a boat motor from freezing. This process, also known as fogging the motor, helps to prevent corrosion and freezing. Here is a detailed guide on how to perform this task:

Firstly, remove the engine cover from the engine. This will provide access to the necessary components. Next, start the boat motor and let it run idle at approximately 1,000 RPM. This is an important step to ensure the engine is running optimally during the spraying process. Once the engine is idling, you can begin to spray.

Use a marine engine fogging oil and spray it into the carburetors until the engine stalls. This may take a few minutes, so be patient and ensure that the engine has completely stalled before moving on to the next step. After the engine has stalled, it's time to remove the spark plugs. This will allow you to access the spark plug holes for spraying.

Once the spark plugs are removed, take your fogging oil and spray approximately 1 ounce (30 millilitres) of the solution into each spark plug hole. It is important to use the correct amount to ensure effective protection. After spraying the spark plug holes, crank the engine for 30 seconds. This step helps to distribute the fogging oil throughout the engine and ensure that it reaches all the necessary components.

Finally, spray the spark plug tips with the fogging oil. Reapply the spark plugs and the engine cover. Ensure that everything is securely fastened. This entire process of spraying the carburetor inlets and spark plug holes should take approximately 10 minutes to complete.

It is important to only use a marine-grade fogging spray designed for this purpose. This will ensure that the solution is compatible with your boat's engine and provide effective protection against corrosion and freezing.

Frequently asked questions