When boating season in the Pacific Northwest wraps up from May to the end of August, the number of boats on lakes, rivers, and channels diminishes with the colder temperatures. Whether you store your boat in your garage, under cover, or in a boathouse, it’s crucial to winterize it to avoid significant damage and ensure it's ready for the next season.

Why Winterization is Crucial

  • Prevent Freezing Damage: Water trapped in lines, filters, and the engine block can freeze and expand, causing severe damage.
  • Rust and Corrosion: Standing water can lead to rusting engine components. Acidic, corrosive wastes, salt, and corrosion buildup can damage the engine's delicate parts.
  • Fuel Degradation: Fuel can break down or become dirty, further damaging engine components.

Understanding the importance of winterization is the first step. But what exactly does winterizing a boat entail?

Comprehensive Winterization Process

At Union Marine, we ensure your boat is thoroughly protected over the winter. One key aspect of our premium winterization service is running all engines on RV non-toxic antifreeze. This method ensures no drain plugs need to be reinstalled in the spring. The engines are fully “pickled,” leaving no room for rust or scaling in the water passages.

The Importance of Regular Maintenance

Winterization isn’t just about protecting your boat from cold weather. It's also the perfect time to service your boat. By inspecting the engine and systems at the end of the season, we can identify and address any issues, ensuring no surprises come spring. Fresh oil changes for the engine and transmission or lower unit are crucial, as is treating the fuel system.

  • Fuel System Treatment: Ethanol in fuel can cause significant issues, as it deteriorates faster than straight gasoline, leading to deposits in fuel lines, carburetors, and other parts. Proper fuel treatment prevents these problems.

Debunking Outboard Engine Myths

A common misconception is that outboard engines don’t require winterization. This is false. Each year, we replace numerous outboard engines due to improper winterization. Beyond removing water, we treat the fuel systems and run the engine on a brine mix to coat the engine cylinders with a light oil layer, preventing rust and condensation.

The Union Marine Advantage

Union Marine offers a full range of winterization services, from basic winterization to a comprehensive premium package, including shrink wrapping and winter storage. For those with busy schedules, we provide pick-up and drop-off services and on-site winterization through our mobile service team. We also offer full system winterization for larger vessels, including generators, air conditioning systems, water systems, live wells, fish boxes, and ballast systems.

Ensure your boat is ready for the next season with Union Marine. Schedule your winterization appointment today!


By following these guidelines, your boat will be well-protected and ready to hit the water when the next boating season begins. Contact us at Union Marine to learn more about our winterization services and how we can help maintain your boat’s performance year-round.