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How to Fix a Drowned Outboard

How to Fix a Drowned Outboard - Photo by Maria Karlsson
How to Fix a Drowned Outboard – Photo by Maria Karlsson

I was running a sailing and diving trip in the Leeward Islands one winter for the Raleigh, N.C.-based outdoor adventure company, Broadreach (gobroadreach.com). We were anchored off of St. Barth’s while our dive instructor took our six students out in the big RIB and accidentally flipped the boat in the surf (no casualties, save for a few dive weights).

The 40hp Yamaha was submerged for over two hours before we were able to right it. Following the tips below, we had it working again the next day, and for the remainder of the three-week program. So pay attention – the tips work!

How to Fix Drowned Outboard


  1. First and foremost, ensure you haven’t done any damage to the environment from leaked fuel or oil, and if so, take care of that first through appropriate channels. Don’t lose sight of the big picture.
  2. Then get the motor out of the drink quickly and rinse it thoroughly with fresh water – most importantly, do not let it dry. Once the water begins to evaporate, corrosion will set in and can cause permanent damage, especially if the engine was submerged in saltwater.
  3. Remove the spark plugs, fuel lines and carburetor, liberally applying WD-40 as you go to remove the water (“WD” after all, stands for “Water Displacement”).
  4. Spray inside the cylinders, or better still, rinse the chamber with methylated spirits. Again, water is the enemy.
  5. Remove the carburetor, carefully wipe it clean and douse it with WD-40.
  6. Hand-crank the engine while it’s disassembled – this will physically force out whatever water is left in the cylinders (usually lots). Without spark plugs and compression, this is surprisingly easy so don’t snap the pull cord. When it feels sufficiently purged, crank it some more.
  7. Install new spark plugs and reassemble the rest of the engine.
  8. Double the oil mixture in new, clean fuel. Then it’s the moment of truth – if it fires, let it run for at least 20 minutes.
  9. No luck? Disassemble everything, repeat the water removal process and leave the parts and the engine to dry out in the warm sun for a while (don’t put anything in the oven, as is sometimes suggested).
  10. After a few hours, re-assemble and try to start the engine again.

Get the outboard to a professional (especially newer four-stroke models) for a more thorough service after a submerging, even if it does come back to life.

Andy Schell is the former editor of All At Sea SE. He’s a licensed yacht captain and has sailed twice across the Atlantic. Follow him online at andyandmia.net.


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