Flushing your boat’s outboard motor after use is imperative to clean out any corrosive salt, sediment, sand deposits or abrasive waterborne materials. If the motor is not flushed, a build-up of sediment will occur in the cooling passages, which can then lead to overheating and possible engine failure. All engine manufacturers recommend flushing when the motor is used at sea, in brackish water and even in fresh water that has a high mud or mineral content.
Most motors either use the “ear muff” flushing system, the direct hose connector method or the flushing bag method. The “ear muff” method, entails fitting the flush muffs over the engine’s gear case and covering the water intakes. A hose is then connected to the flush muffs and run for about 10-15 minutes to clean out any sediment.
Flushing is the only way to protect the cooling system of the motor and should be done each time the boat leaves the water. The flushing bag cleaning system requires the propeller and water intake screens to be immersed into the flushing bag which is filled with clean, fresh, water. The motor is then switched on (in neutral) and the cooling system is cleaned of salt and sediment by the action of the freshwater moving through the cooling system. A large plastic drum can be used instead of a flushing bag.