How to Flush Your Outboard Motor After Every Use

Flushing your outboard after every saltwater use takes under five minutes and prevents salt build-up in the internal cooling passages that circulate water through the engine block.

Why saltwater flushing matters

Left untreated, salt residue corrodes cooling passages from the inside over time — a slow, invisible process until it eventually causes overheating.

Muffs vs flush-port method

Flush muffs clamp over the water intakes with a hose running to them, simulating being in the water while the engine idles on the trailer. Engines with a built-in flush port let you connect a hose directly, without needing muffs.

2-stroke vs 4-stroke differences

Both engine types benefit equally from flushing — the cooling system being protected is separate from the combustion cycle, so this step applies regardless of engine type.

See our full maintenance guide for the complete seasonal care schedule.