Good Points - Quick, easy and effective method of flushing outboard

Bad Points - Noisy. The exhaust is out of the water. The water normally acts as a muffler.

There are flushing mufflers available that connect to the propeller to reduce noise.

Worn flushers may not seal properly and may not provide the water pump with enough water to pump through the engine. Always inspect flushers and replace as required. Always squeeze the flushers together to improve clamping pressure.

Does not wash the exhaust cavity of the gearcase very good.

Flushers may fall off while running the engine. Always stay and observe the outboard while it is running on the flushers.


Always check that the earmuffs are in good condition and they suit your particular outboard.

Using the large rectangular type flushers is not suitable for some outboards as it sits up on the rounded part of the gearcase and does not get a proper seal. The small round ones are the best ones for most applications. Make sure the flushers cover the whole water intake screen.

Check the edges of the flushers for perishing and cracks etc. and replace as required.

Always squeeze the flushers together before use to ensure they have adequate clamping pressure.

Depending on your outboard, the flushers could be mounted from the front or back. If mounted from the front they can easily fall off so careful monitoring is required. If mounted from the back, ensure the frame is up and out of the way of the propeller.

Look under the anti-ventilation plate for secondary water pick- ups. These are designed into the outboard so if a plastic bag covers the main water pick-ups, the water can still get to the water pump via the secondary water pick-ups. If you have secondary water pick-ups, cover them with some duct tape. Don’t forget to take the tape off when finished.

Ensure there is good water pressure. Most outboards have an indicator that will squirt water horizontally if there is enough water pressure. If you don’t have good water pressure then this procedure should not be used.

Always turn the water on first before starting the outboard and last after finishing running the outboard. Running the engine for even a short period can cause serious damage to the water pump.

Start the engine and check that the tell-tale is operating. You can tell if there is water running through the outboard by a flow of water coming out of the centre of the propeller.

Run it at idle for a short time to allow it to warm up. The outboard should not be run at high revs while on the flushers. There is no need to put the outboard in gear for flushing.

Bring the neutral revs up a bit to allow extra heat and water flow to be generated. This will cause the thermostat to open more and be better flushed.

Stay with the outboard while it is running on the flushers. The flushers could fall off, the hose connection may blow off the tap, someone might use the tap and turn the water off or a car could park on the hose. Stay with the outboard while it is running on the flushers.

After around 10 minutes of flushing, turn the engine off first and then turn off the water.

Now apply the MACS or Salt-Away - Post Flushing Treatment as per the manufacturers’ instructions.

Don’t forget to remove the duct tape from the secondary water pick-up screens if this applies to your outboard

- Contact Cairns Outboard Service for your outboard service requirements.

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