Cleaning the outboard engine after each ride is the single most important factor of longevity for every outboard engine. Salty water that circulates in the engine block for cooling during normal operation may be the root cause for a wide variety of issues.
When the outboard is removed from the water, the salt inside the walls gets dried and forms a layer of hardened material that reduces heat discipation.
In order to clean the salt from inside the engine, you can use an outboard engine washer that helps feed fresh water on the water inlet in the lower unit and cleans the whole engine.
You can download the model in various formats as well as the native file in solidworks format.