# Flushing a saltwater outboard. How long and how often?



## SPC (Nov 26, 2009)

I can't use the hose attachment option to flush my Honda 5HP. Instead, I run the outboard in a bucket with fresh water being added as the fresh water in the large plastic container is circulated through the motor and gives me a shower -- boat on the trailer on the hard after sailing. 

How long do I need to flush (running at near idle in neutral in a bucket) and do I need to do it every time that I sail? 

Thanks


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## casey1999 (Oct 18, 2010)

I used to have a 35 hp Honda outboard. I used the "ear muff" type device you just stick on to cover the cooling water inlet of the engine. I would run the engine at idle or a little more for maybe 5 minutes to flush. Did this after every use.

The West Advisor: Outboard Motor Care


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## sea_hunter (Jul 26, 2000)

I flush every time I use it.


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## Classic30 (Aug 29, 2007)

A good question.

Since it's not really a good idea to leave fuel to evaporate in the carburettor, my suggestion would be to start it up on idle in the bucket as you do now, then disconnect the fuel line and leave the motor to run itself out of juice. You'll find that's more than long enough to flush the engine out.

Unless you're out on a daily basis, yes, you really should flush it after every time you sail.


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## casey1999 (Oct 18, 2010)

Hartley18 said:


> A good question.
> 
> Since it's not really a good idea to leave fuel to evaporate in the carburettor, my suggestion would be to start it up on idle in the bucket as you do now, then disconnect the fuel line and leave the motor to run itself out of juice. You'll find that's more than long enough to flush the engine out.
> 
> Unless you're out on a daily basis, yes, you really should flush it after every time you sail.


That is a good idea. Now I remember I used to do that with my honda (been 10 years since I had the engine). With the alchol in the fuel now, good to have the carb dry of fuel. I never had a fuel problem.


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## Minnewaska (Feb 21, 2010)

My OB is on the dinghy and gets used about once per week. Sometimes more often. I must be a heretic, because I've never flushed an outboard during the season. It does get flushed at the beginning and end of every season, when I change the oil and run her up on the hard. (I rechange the oil that has been sitting all winter) Coincidentally, I pulled an internal zinc last year and could see inside the motor. There was very little scale and the zinc still looked brand new. Motor was 6 years old at that point and I would estimate had five hundred hours on her. 19.9hp Tohatsu

p.s. Never flushed a dozen other OBs I've had over a lifetime either.


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## dabnis (Jul 29, 2007)

I have done it both ways. Had a 15HP two stroke on a Coronado 25 for many years, never flushed it, no problems. However, had a 35HP two stroke on my fishing boat that I flushed every time I used it in salt water. Had to replace the thermostat and was very surprised as to how much salt or other? debris was inside the water passages. Suggest you flush when you can, can't hurt anything assuming you are getting proper water flow. And yes, drain the carb or run the fuel out if you are not going to use it in a few weeks. 

Paul T


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## tommays (Sep 9, 2008)

Most outboards live there whole life on a mooring and NEVER get flushed SO anything you do is GOOD


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## Classic30 (Aug 29, 2007)

Tommays, just because the boat is on a mooring doesn't mean you can't flush the outboard at least once in a while. The bailing bucket filled with fresh water and shoved under the drive legs works just as well on smallish outboards as it does on land.

..but, you're right - many people simply don't bother and will get away with it for a few years anyway... before it becomes more useful up the other end - as an anchor.


Why?: Most (all?) outboards use aluminium alloy for the engine block - to keep the weight down. If the outboard is used regularly, there is no real chance for corrosion to develop, BUT... if you use the boat a lot and don't flush afterwards and then for unplanned reasons don't use it for an entire season or so, the salt residue gradually closes up the cooling passages so that next time you start 'er up she overheats.. and warps.. and your day out on the water goes downhill from there.


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## Minnewaska (Feb 21, 2010)

I would nearly agree with tommays. Most outboard NEVER get flushed, during the season. Unless you never change the oil, its hard to imagine they never get flushed at all. Just to warm up the oil and check for leaks, you have to connect a water supply to run the motor. That's the only time mine gets flushed. At the beginning and end of each season.


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## Tallswede (Jul 18, 2012)

I generally flush mine with fresh water every time I pull the boat out of the water. I never know how long the boat will be sitting until I get back to use it. Corrosion can set in if salt water is left in the cooling jackets. An engine that is used regularly doesn't seem to corrode as quickly. Also, most of the newer outboards are made of more durable stuff it seems.

Kevin


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