How to Save a Drowned Outboard Motor

Written by dale yalanovsky
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How to Save a Drowned Outboard Motor
You can bring back a drowned outboard motor. (toy outboard motor image by pearlguy from

A drowned outboard motor will require specialised treatment. Interior metal pieces will begin to oxidise, or rust, as soon as contact with water occurs. The difference between a running outboard motor being submerged and a outboard motor that is not running being submerged is paramount. In the latter instance, the motor has remained sealed and will run again with minor maintenance. A running motor will ingest water into the cylinder head and require extensive maintenance. If the motor does not run after you perform basic procedures, take it into a professional outboard mechanic for service.

Skill level:

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Things you need

  • Fresh water hose
  • Bucket
  • Spark plug wrench
  • Methyl alcohol
  • Spray lube
  • 55-gallon barrel filled with water

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  1. 1

    Remove the cowling cover on the motor. Covers are held on by small latches on the side that are flipped open. Wash off any weeds, mud or sand with a hose and fresh water.

  2. 2

    Drain the fuel into a bucket. Remove the fuel line by loosening the fuel line clamp, pulling the line off of the carburettor and allowing it to drain into a bucket.

  3. 3

    Remove the spark plug(s) with a spark plug wrench. Tilt the motor on the side so that the spark plug hole(s) face downward. Hand-crank the motor. Water will purge out of the cylinder this way. Any grinding noise means sand has got into the cylinder head. Stop hand-cranking immediately. If you hear any grinding, take the motor into a qualified professional for an engine overhaul.

  4. 4

    Pour methyl alcohol into the cylinder head through the spark plug hole. Methyl alcohol is common in gas line antifreeze solutions that normally are poured directly into a gas tank. The alcohol will absorb and flush water out of the cylinder head. Allow this solution to drain into a bucket.

  5. 5

    Spray the inside of the cylinder with a spray lube. Coat the insides liberally while hand-cranking the motor. Spray lube into the carburettor air intake while hand-cranking. This will purge any water that has lodged in the carburettor jets.

  6. 6

    Reassemble the motor and mount it on a 55-gallon metal barrel filled with water. This will be your test bed.

  7. 7

    Start the motor. Hook up the fuel line with fresh gas in the tank. Prime the engine like you normally would. Although not recommended, you may need to use starting fluid for the initial ignition sequence. Spray starting fluid directly into the cylinder through the spark plug hole.

  8. 8

    Allow the motor to run for at least 30 minutes under load. Once running, gas flow through the carburettor and the cylinder will remove any excess water that remains. The heat of the motor will boil off or cause evaporation of any water that has settled on electrical parts.

  1. 1

    Remove the cowling cover by flipping open the cover latches on the side. Rinse off all lake residue like mud or weeds that have accumulated beneath the cowling.

  2. 2

    Place the motor on a 55-gallon metal barrel filled with water. The motor mounts will drape over the edge of the barrel while the drive train will rest inside of it.

  3. 3

    Start the motor. Spray starting fluid into the air intake, and once the motor is running, keep it running for 30 minutes to purge any water that made its way into the carburettor or the cylinder head.

Tips and warnings

  • If an outboard motor falls into salt water, take it into a qualified professional for cleaning and/or rebuilding.

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