Back in the day, flushing an outboard with fresh water was done only one way. A set of "ear muffs" or "flush muffs" was fitted around the engine's gearcase to cover the water intakes, connected to a garden hose with a good water supply, and the engine was run for five to 10 minutes. But today's outboards can be flushed using other, sometimes easier methods, without even starting the engine.