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Winterizing a Saltwater Fishing Boat

Winterizing a boat is a must do activity for all boat owners if you don't expect to use your boat for an extended period of time. By winterizing your boat every year and also doing some preventative maintenance along the way, you can enjoy your boat and motors for years to come. Here's my checklist I run through every offseason for my saltwater fishing boat.

winterizing a saltwater fishing boat

My Checklish: Winterizing a Boat

  • I always add the appropriate amount of fuel stabilizer to my fuel tank before the final fuel up. Something to consider: I also started adding an engine and fuel care system cleaner (Quicksilver Quickleen) periodically. My plan is to add this at every oil change (100 hours) and at the end of each fishing season. Quickleen and similar products help eliminate excess carbon build-up in your engine.

  • Fuel up your tanks, and run your outboards for ~ 5 minutes to mix up your additives but also to raise the temperature of the engine so all the oil will drain easily.

  • Perform oil, filter, and gasket seal changes on the outboard engine. This is a normal 100 hour outboard maintenance. I do this regardless of the number hours on the engines with the current oil. My boat sits for about 6 months and I want it to have fresh oil. This is also a great time to inspect your lower unit lube to see if any water is present. If there is, your lower unit needs to be repaired before your next outing.

  • Once the oil is changed, this is when I flush the outboards with freshwater and salt removing cleanser. First, I run freshwater and the salt removing cleanser through the freshwater hose hookup port without the motor running. Then I attach the muffs to the lower unit to flush the engine. Once the muffs are on the outboard with a tight seal, I start the engine and allow the engine to warm up. This ensures the freshwater and salt removing cleanser runs through the thermostats.

  • Remove and inspect spark plugs. Spray fogging oil into each cylinder. Turn key over for a second. This allows the oil to coat the walls of each cylinder. I replace my spark plugs every other season.

  • Inspect/replace anodes.

  • Disconnect batteries. I always take my batteries off the boat, clean them up from any corrosion, and put on a battery maintainer. I also take my expensive electronics off the boat and store inside.

  • I perform a thorough cleaning and rinse of the entire boat, outboards and trailer. I use a salt removing cleanser along with plenty of soap and bleach. I also take off the outboard covers and spray with freshwater. After the outboard is dry, I spray the engine components with a protective barrier such as Corrosion-X or Yamashield.

  • To consider: The end of the season for me usually means it's also time for 300 hour maintenance on the outboards. This usually includes impeller change, thermostat, in-line fuel filter, regular fuel filter, and accessory belt inspection/replacement. To do an impeller change, the lower unit needs to be removed. On a mercury verado outboard, the main engine oil also needs to be empty before removing the lower unit.

  • As I'm cleaning the boat for the final time, I take notes of items I want to replace and change prior to next season. Physically write these down either on a piece of paper or on your phone. This will help you consider your options, and get you on the water more hassle free when it's time to go fishing again.

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