If you have lifted out for the winter and have not winterised the engine, you may wish to run the engine occasionally. Here is a method which I have used very successfully to supply water for cooling, without the need for a large quantity of water on hand.

Cut a hole near the top of a clear 2.5 or 5 litre container to fit the exhaust/water outlet. Fill with water to below the cut hole and secure this in some way to the boat (see picture). Attach a length of hose to the water pump inlet and fill this with water. The idea is to create a siphon, so keep a finger over the end while putting it into the water in the container through the top opening.

Start the engine and water will be drawn out of the container, through the engine and back into the container. I have been able to run my engine for a lengthy period in this way, instead of having to keep filling a reservoir. Do not forget to add anti-freeze to the water if any water is to remain in the engine.