Aux 2 Unit 17 Q7

If an outboard motor has been submerged in seawater, immediate and thorough action is essential to minimize damage and prevent long-term issues such as corrosion and mechanical failure. Saltwater is particularly harmful to outboard motors due to its corrosive nature, so quick intervention is crucial.

Procedure for Handling an Outboard Motor Submerged in Seawater:

1. Remove the Motor from Water Immediately

• Action: Retrieve the outboard motor from the water as soon as possible to stop further water intrusion and reduce the exposure to saltwater.
• Reason: The longer the motor remains submerged, the greater the risk of corrosion and internal damage.

2. Do Not Attempt to Start the Motor

• Action: Do not attempt to start the engine until it has been thoroughly cleaned, inspected, and dried.
• Reason: Turning the engine over with water inside can cause serious damage to the internal components, particularly through hydrolock (when water enters the engine cylinders).

3. Flush with Fresh Water

• Action: Thoroughly rinse the entire motor, especially the external components and engine housing, with fresh water to remove salt and debris.
• Reason: Freshwater rinsing will help prevent salt buildup and corrosion on the exterior surfaces.

4. Drain and Remove Excess Water

• Action:
  • Remove the spark plugs: Take out all the spark plugs to relieve any compression in the engine.
  • Drain water: Tilt the motor to allow water to drain from the exhaust, intake, and other internal cavities.
  • Manually turn the engine: If possible, manually turn the flywheel or use the pull cord (if applicable) to expel any water inside the cylinders. Do this carefully to avoid forcing water further into the engine.
• Reason: Draining as much water as possible will help minimize internal corrosion and damage to moving parts.

5. Flush the Cooling System

• Action: If the motor has an internal cooling system, use fresh water to flush the system thoroughly. Some motors are equipped with flushing ports, but if not, attach a hose to the water intake and run fresh water through.
• Reason: This will clear any saltwater from the cooling passages, reducing the risk of corrosion in the cooling system.

6. Remove and Drain the Carburetor (if applicable)

• Action: Remove the carburetor (or fuel injection system) and drain any water that may have entered. Clean it thoroughly with fresh water and air-dry it completely.
• Reason: Water in the carburetor or fuel injection system can lead to fuel contamination, poor engine performance, or internal damage.

7. Drain and Replace Fuel

• Action: Drain the fuel tank, fuel lines, and any fuel in the engine or carburetor. Replace the old fuel with fresh fuel.
• Reason: Water may have entered the fuel system, contaminating the fuel and causing problems when the engine is restarted. Fresh fuel ensures the engine runs properly when restarted.

8. Drain and Replace the Engine Oil

• Action: If the outboard is a four-stroke engine, drain all engine oil immediately, as water may have contaminated it. Refill with fresh oil and repeat the process until the oil is completely free of water (the oil will initially appear milky if water is present).
• Reason: Water in the engine oil will reduce lubrication and cause severe internal damage to the engine components, such as bearings and pistons.

9. Dry the Electrical System

• Action: Carefully dry the ignition system, electrical wiring, and all electrical connections. Use compressed air, a soft cloth, or electrical contact cleaner to remove any moisture.
• Reason: Water in the electrical system can cause shorts, corrosion, or failure of critical engine components such as the starter motor or ignition system.

10. Lubricate and Protect

• Action: Apply an appropriate corrosion inhibitor (such as a marine-grade lubricant or anti-corrosion spray) to all exposed metal parts, including the moving mechanical parts, to prevent corrosion. Focus on the linkages, throttle cables, and control systems.
• Reason: Seawater can cause rapid corrosion of metal parts, which can lead to seizing or failure of components if not properly protected.

11. Inspect the Gearbox and Propeller

• Action: Check the gearbox oil for signs of water contamination (the oil will appear milky). Drain and replace the gearbox oil if water is present. Inspect the propeller for any damage or fouling.
• Reason: Water in the gearbox can damage bearings and gears, leading to expensive repairs. Ensuring the propeller is in good condition is essential for optimal performance.

12. Reassemble and Test Run the Motor

• Action: After ensuring the engine and all components are thoroughly dried, cleaned, and lubricated, reassemble the motor. Install new spark plugs, refuel the engine, and restart it.
• Reason: Test running the motor after a thorough inspection allows you to verify that the engine is operating correctly and that there are no lingering issues.

13. Monitor and Perform Further Maintenance

• Action: After the engine is restarted, monitor its performance closely. Run the engine for 20–30 minutes to ensure proper operation. Perform additional checks after the engine has run, such as inspecting oil quality and checking for leaks.
• Reason: Some problems may not be immediately apparent, and continuous monitoring ensures that any potential issues are addressed before causing significant damage.

14. Seek Professional Assistance (if necessary)

• Action: If you are not able to complete the procedure yourself or if the motor shows signs of significant internal damage, take it to a qualified marine mechanic as soon as possible.
• Reason: A professional mechanic can thoroughly inspect and repair the motor, especially if internal parts like the pistons, cylinders, or electrical components are affected.

Summary:

If an outboard motor is submerged in seawater, swift and thorough action is critical to minimize corrosion and damage. The process involves flushing the motor with fresh water, draining any water from internal components, cleaning and drying the electrical systems, and replacing fluids such as oil and fuel. Additionally, protective measures must be taken to prevent future corrosion, and the motor should be closely monitored during the test run. In severe cases, professional repair services may be required.