Before you pull out of the water (or before you take it out of the bucket), disconnect the fuel line at the engine, and continue to run the engine at a low-mid idle speed until the engine sputters and dies, at which point the carburetor should be empty of most of its fuel. This could take a minute or two.
If you later need to lay the motor down for short periods, you can lay it on its "back" (with prop towards the ground) which keeps the fuel port facing up.
The next part requires a standard disclaimer - Not EPA approved, but better than many alternatives. Wear nitrile gloves (not latex) for this. Don't do this near the campfire or while smoking. etc.
If you need to lay it down for longer durations or for transport, or if you must lay it on its side, try this. Support the motor's weight and tilt the motor towards the fuel port/connection (towards tiller's end) while holding a small cloth over the fuel port/connection. Push in the pin in the middle of the port and it will allow any remaining fuel to drain out into the rag. Note that you will now have a fuel-soaked rag, and possibly your hand as well (I use nitrile glove for all this). Air the rag out adequately before disposing, or fire may ensue... Don't drain it like this over water or the ground... Yes, it's probably only a teaspoon of fuel, but it's better in the rag you can dispose of than in your trunk.
I'm open to better suggestions, but this is my procedure.
