Is antifreeze necessary for an outboard motor?

As winter approaches, many boaters begin to wonder if they need to use antifreeze to winterize their outboard motor. The short answer is yes, antifreeze is necessary for an outboard motor if you live in an area where temperatures regularly drop below freezing.

Antifreeze plays a crucial role in protecting your outboard motor from damage caused by frozen water. When water freezes, it expands, which can cause engine block cracks, busted hoses, and other water-related issues. Antifreeze, however, is designed to lower the freezing point of water, so it doesn’t turn into ice.

While antifreeze isn’t necessary for outboard motors that are used year-round in warm climates, it’s essential for those who boat in colder regions. If you live in an area where the temperature frequently drops below freezing, you should add antifreeze to your outboard motor before storing it for the winter.

When adding antifreeze, it’s essential to use the correct blend, which is typically a 50/50 mixture of antifreeze and water. This blend will provide the necessary protection for your outboard motor without causing any damage to the engine.

To add antifreeze to your outboard motor, you should follow these simple steps:

1. First, you should flush your outboard motor with fresh water to remove any salt or other contaminants.

2. Next, remove the water hose from the outboard motor and attach a flushing adaptor or a bucket of water to the lower unit.

3. Start the engine and let it run until the water that comes out of the exhaust is clear.

4. Once the engine has been flushed, disconnect the water supply and wait for any remaining water to drain out of the system.

5. Place a container under the water pump pickup and slowly pour antifreeze into the container until it comes out of the tell-tale hole.

6. Turn off the engine and allow it to cool, then remove the spark plugs and spray fogging oil into each cylinder. This will help prevent rust and corrosion while the engine is not in use.

Antifreeze is necessary for an outboard motor if you live in an area where temperatures regularly drop below freezing. It’s a simple and effective way to protect your engine from damage caused by frozen water, so be sure to add it to your winterization process. By taking these steps, you’ll ensure that your outboard motor is in top condition when it’s time to hit the water again.

Have something to add or correct? Please let us know by clicking here.
* See disclaimer in the footer of the site for use of this content.

Related Questions


Latest Posts

Don't Miss

Our Newsletter

Get the latest boating tips, fishing resources and featured products in your email from!