Rob Melotti gets one-to-one tuition on caring for a 4-stroke at the Honda Institute

How to care for an engine that has been immersed in water

If your 4-stroke outboard goes overboard, you have a big problem. In salt water with the engine running, you’ll be lucky to get it back to working order – water in a crank case will not compress and can bend the metal components in the engine. Rust can begin to take hold in hours once metal elements are exposed to the air after immersion. But if you drop your outboard off the pontoon or it gets dislodged from the stern of your tender when not in use – the following steps (which are in the manual for this Honda 6hp) taken immediately upon recovery, may be enough to get you home, but the advice from Honda is to get the engine to your nearest service engineer as soon as possible.

Honda BF6 immersed outboard recovery

1. Secure the engine upright, remove the lid and wash away any debris. Avoid putting any more water into the carburettor or air box.

2. Shut off the fuel feed and drain the carburettor (see previous page step by step).

Honda BF6 - remove spark plug

3. Detach the Killcord and the spark plug cap and remove the spark plug.

Honda BF6: drain water cooling systems

4. Gently pull the starter coil to expel any water from crank case

5. Replace engine oil and attend to sump plug washer (see previous page step by step).

Honda BF6: lubricating cylinder bore and piston rings

6. Put drop of oil on piston head and turn engine over manually

Honda BF6 cleaning spark plug

7. Clean spark plug with tissue or, unless your engine is fitted with Iridium plugs, a wire brush.

8. Replace spark plug

9. Start the engine

10. Replace the oil again after 30 mins usage

  1. 1. Draining the carburettor
  2. 2. Storage tips for small 4-stroke outboards
  3. 3. Changing engine oil on a Honda 4-stroke outboard
  4. 4. How to care for an engine that has been immersed in water
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