Papag wrote:Another rookie question: [when] taking a boat between fresh water and saltwater, does it matter which engine I have? [I] see "salt[water]" in some [outboard engine] model [names].
Is "salt[water]" a marketing term or a technical difference?
The history of engine model designator with the word “saltwater”: at one time outboard engines were used most in freshwater lakes, and use in saltwater was not very common. As outboard engines became more powerful and could be used on larger boats, outboard engines began to more frequently be used in saltwater. This gave rise to special models that were more expensive because they used more corrosion-resistant components. These models were often designated as a “saltwater” model. Today outboard engines are generally all made to be corrosion resistant as much as possible, and there are no special saltwater models.
Generally the upgrade to an outboard to become the "saltwater" model was limited to a few external engine components, like the steering tilt tube or some external fasteners. If buying an older engine that has been used extensively in saltwater, it will already be apparent what parts of the engine have suffered corrosion from saltwater.
There is no harm in taking an engine from saltwater to freshwater. It actually will be good for the engine to be flushed out. Taking an engine from freshwater to saltwater will not be particularly beneficial.
My own experience with occasional use of an outboard engine in saltwater: I would extensively flush the engine with fresh water.
An anecdote: while trailering my boat back to Michigan from the Washington where it had been in operation for two weeks in the Pacific Ocean, I pulled off the highway at the first opportunity with freshwater and a boat ramp nearby. I backed the boat into the freshwater and started the engines. I let them run at fast idle for about 15-minutes in order to flush out all the saltwater in the engine cooling system. It was about 1 a.m. in the morning so there was no waiting at the boat ramp.