Flushing Outboard Motor with Fresh Water

[Etienne Botes]

Thank you all for all the replies, much appreciated!!

[Celestialsailor]

Geeezz!!! Now I feel like a fool. I ..have religeously flushed my Tohatsu 6hp 4stroke after every use...

[twisty]

I flush my bigger outboard once a week if it has been used. If I understand the reason for flushing it properly it is to keep the salt from crystalizing inside. But it makes sense if you are using every week that it really shouldn't be a problem

[waverider]

To flush or not to flush. Never hurts to do it, but most of us dont on a regular basis. I have a 9.9 Johnson Sailmaster that starts first push of the ignition, I only give it a rinse after the season is ended. Now, I keep my boat in the Lahave river which is a mix of Ocean salt and lake fresh water. Still it is a lates 80's model and it never quit's on me.

I do take it in every season and have the Carb's cleanned and a new impeller put on. All nipples greased and new lower end oil. This winter cleanning cost me about 150.00.

Cheers

Todd

[oceansoul63]

I wondered the same thing when I switched from motor boats to sailboats. On my old bowrider, I was religious about flushing the motor after every use.

For my cruising sailboat, I use a dinghy with a 4.5 Johnson Sea Horse ('80s). I noticed that none of the other people in the anchorage where I keep my boat ever seemed to flush their dinghy motors, and asked a few of them about it. The consensus was pretty much the same as it is here -- if you're using it every day (or every other day), it's not such a big deal.

So, the only time I ever flush it is if I'm not going to use it for a while. After almost a year of constant use, I have only flushed it a couple of times, and it's fine.

[Etienne Botes]

Thank you so much for all the input. It makes most sense to me what Twisty and Oceansoul said. It seems really a matter of "the more you use it, the less the maintenance hassle".

Best!

[emeraldsea]

No big deal if you are using it regularly, its when it drys out that salt crystals will start, which will start to restrict cooling flow. Most outboards are pretty durable, but many inboard outboards have had major problems due to neglected raw water manifolds. I flush my merc 90 4stroke every time I take it out of the water if possible, but after a couple seasons the thermostat gets corroded causing the engine to run cold and condensate, which will kill my engine if I don't stay on to top of it. For the new diesel in my sailboat, I just plumbed in a flush system so that I can easily flush with fresh water and drain, when I'm not going to use it for a few weeks or more.

[elrodqfudp]

A word of warning about the new garden hose fittings for engine flushing. DO NOT RUN THE ENGINE!! These units do not supply water to the water pump. If you run the engine you burn up your impeller and shortly after that your engine overheats or seizes if you are not looking.

[GordMay]

Freshwater Flush: a manufacturer's recommended flushing technique:

Caution: To avoid injury in the event of accidental starting, be sure to remove the prop and the stop switch lanyard cord from your outboard before proceeding.

Important: All Tohatsu and Nissan outboards are water cooled; running your outboard without an adequate source of cooling water will result in severe damage to your outboard.

2.5, 3.5, 4, 5, & 6hp:
For smaller outboards, the simplest way to flush your outboard is by using a large container of water (bucket, pail, barrel). Be sure the container is large enough to completely cover the water intake ports on the lower unit of the outboard. Also be sure that the container is wide enough so that no part of the motor will touch the sides/bottom of the bucket. Securely mount your outboard on a sawhorse or other sturdy device that will allow safe operation of your outboard. You may also use an optional "flushing plug", see below.

8hp and up:
With 8hp-140hp outboards we recommend you use a motor flusher ("ear muffs"). This type of motor flusher is easy to use, inexpensive, and available at virtually every marine retailer. This equipment attaches to your garden hose and clamps on to your outboard's lower unit, covering the water intake ports. Turn the garden hose on fully before starting your engine. Make sure the "ear muff" motor flusher is firmly in place and correctly positioned over the water intakes on your lower unit. (Note: the "ear muff" motor flusher will not work on outboards below 8hp.

Run your outboard at normal idle speed for 5-10 minutes to allow the engine to warm up and to ensure your outboard is thoroughly flushed with clean water. DO NOT rev up the engine as this is not necessary for flushing and could cause damage to the water pump.

Flushing Plug Attachment:
The flushing plug attachment is available for all outboards ($14.99). It is a bit cumbersome to use and requires removal of a water bolt on the engine. Once the water bolt is removed, the flushing attachment can be used. After flushing, the flushing attachment is removed and the water bolt is re-installed. When using the flushing plug method, the engine should NOT be operated while flushing.