How to Winterize a Yamaha Jet Boat

When winter weather sends you off the water and indoors for part of the year, winterizing your Yamaha Jet Boat will help protect it from the elements and keep it in good shape for the spring. The winterizing process includes taking steps to clean and prepare the engine and carburetors for a period of disuse, replace the spark plugs for storage, remove excess water and cleaning the exterior of the jet boat.

Things You'll Need

  • StaBil fuel treatment
  • Fogging oil
  • Water hose
  • Flush hose
  • Antifreeze
  • Desiccant plugs
  • ArmorAll
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Instructions

    • 1

      Add the StaBil to your fuel tank before you take your Jet Boat out for the last time of the season. Let the engine run about 2 hours with the StaBil in it. After your last outing, add another bottle of StaBil and fill the tank with fuel.

    • 2

      Flush your engine. Turn on the water hose and let it fill with water. Then turn it off. Turn on your engine and attach the water hose to the flushing system. Turn the hose back on. Let the water flush the engine for about 30 minutes.
      Turn off the hose first and then the engine. Running the hose into a non-running engine can damage the cylinders.

    • 3

      Attach the flush hose to the container of antifreeze. Flush the antifreeze through the engine the same way you did with the plain water.

    • 4

      Remove the flame arrestor screens. Start one engine and spray the fogging oil into the engine. It will smoke and cough, but keep it running and keep spraying the oil into the carburetor. After 15 seconds, spray in a large amount of oil to make the engine stop running. Repeat the process for the other engine.

    • 5

      Remove the spark plugs when the engines are cool. Spray fogging oil into the plugs and insert the desiccant plugs.

    • 6

      Drain water from the hull and bilge and run antifreeze through the bilge pump.

    • 7

      Remove any cushions and clean the Jet Boat with ArmorAll on the surfaces. Cover with a breathable cover or tarp. Rotate the cover every few weeks to prevent any mildew or mold buildup.