Flushing outboards?

[Rob Waller]

Outboard makers recommend you flush out the cooling system after using the engine in salt water. I only sail in salt water, and I don't do this except once at the end of the season. Nor do I see anyone else in the marina doing it, and especially not people whose boats are kept on moorings.

Am i being foolish? What do others do? Mine's a 4hp Yamaha 4 stroke by the way.

[Andy Dingle]

Hello all and it's nice to see the forum coming to life again.

Interesting topic Rob, and also one that has interested me for many years. One of those topics that everyone will have an opinion on.

My current supplier and service agent assures me that the second biggest cause of failure of engines is failing to flush the coolant flanges with freshwater and clean out the salt - it eventually solidifies so hard it's virtually impossible to shift.
Incidentally he tells me the biggest cause of failure is not running the engine dry with the fuel switched off if it is going to be left - especially in 2 strokes but also applies to 4 strokes - and the carburettor becoming coated in thick sticky gunky fuel residues as the fuel evaporates.
So I am very keen on sticking to the manufactururers advice to flush it.

I once had a Hunter Horizon 26 with an elec start Tohatsu 9.8 in a well in the port locker, it slid up and down on a slide but access was still difficult - but it had an attachment that connected a hose with a hoselock attachment so that I could flush it regularly. I think tohatsu still supplies this as on option on larger engines? (I love tohatsu's!)

I also used an engine flushing bag that I made up from an old builders sand bag from this idea:

http://www.burgees.com/flushingbag/default.htm

Which is a cracking idea and can be slipped round the leg of the engine even in the water and filled with fresh water to flush the engine. There used to be a product available - (Saltex? or something like that)  that would 'dissolve' salt - I used it a lot on diving equipment, dry suit zips, underwater technical equipment etc. Also used to put it in the flushing water - was expensive but my employer at that time coughed up for it. Not seen it for ages though.

As I currently tow to and from sailing locations I just use the 'ear muffs' that clamp around the engine leg water input, with the engine in situ (weighs about 30 kg) connect a hose and start the engine - cheap, easy and effective. But in my personal opinion absolutely essential ... Flush and be damned I say.


Andy and 'Psalter' - Tohatsu 5 four stroke.

PS Best Chrimbo pressie?
Margaret Dye's 'Dinghy Cruising - The enjoyment of wandering afloat'. £0.01p from amazon (why only 1p for goodness sake - it's a cracking book).

[Ian Cowie]

I agree fully with Andy's comments. I use a flush attachment for a hose on my Honda BF5. I flush and run the engine dry each time I take the boat out of the water. I keep my Coaster on a trailer in the boat pound.

I think the truth is that owners just do not take the trouble and let their engines rot. Those boats on a mooring do find it more difficult but I do like Andy's suggestion of a bag filled with fresh water. A hosepipe from the pontoon would be an obvious help.

Ian Cowie
Drascombe Coaster "Moksha"

[Rob Waller]

Thanks for the tip about running the engine dry, Andy.

I do agree that flushing after every trip is the ideal solution, and for trailer sailers it's not too onerous.

But for people with moorings, it doesn't seem to me to be practical to flush every time you sail. Even if you use one of those bags you have to somehow get it around the engine in the water without salt water getting in, and on a Bayraider you also have the plastic flaps to contend with. Then you have to fill it with fresh water that you have somehow lugged out there in your tender... Which in my case was not kept anywhere near a tap.

Now I'm in a marina there is a least a hose pipe, and I can try to flush using muffs. But I'm not sure how they behave if the engine is hanging into salt water.

Looking at some other forums, I'm getting the impression that people on moorings generally don't attempt to do more than an end of season flush.

[Rob Waller]

A further reflection... I wonder if this isn't an example of a design fault by default... by which I mean that we sometimes assume that a constraint of a first generation technology can never be overcome.

For example, I find it extraordinary that wheels + extendable handles only became a standard feature on suitcases in my lifetime. Decades went by between the decline of the railway porter and the introduction of this simple and obvious idea.

When choosing my outboard, my Yamaha was up against similarly priced and performing models from other manufacturers. I chose it because you can lay it down horizontally any way you want, without risking oil leakage (most four strokes have to be laid in one particular orientation, with the risk that the friend who is helping you gets it wrong, or in an emergency you forget). Yamaha's designers obviously decided it was time to address this constraint.

Perhaps this flushing thing is similar. Could a different material be used to stop salt deposits forming? Or some feature introduced that allows you to simply attach a 2 litre bottle of fresh water and flush it out? Other products don't stand still – steam irons now allow you to use tap water, and kettle designers introduced filters to stop limescale getting in your tea.

By the way, the next constraint I'd like Yamaha to address is the length of the pull you need to get the thing started - I have to make sure no one sits to my right when I start it, in case they get thumped by my flying fist.

[Rob Johnstone]

Re the flush / not flush debate when using outboards in salt water - I have been led to believe that the salt deposits build up around the cooling water temperature sensor in the engines causing the engine to think that the cooling water is hotter that it should be, this causing the engine to cut out. Freddie (the Mecury 6HP that powers Vagabond) ran for about 100 hours last summer and was flushed no more than 4 times in the trip. Once I could get hold of a hose and water supply (not as easy as you would think at some Marinas), it was quite easy as Mercury provide a plug on the side of the engine and fitting (complete with Hozelock snap connector) to screw into it. Once the engine was tilted to get the prop out of the water, the hose could be connected and flusing commenced. Incidentally, the Mercury instructions tell you not to run the enginer whilst flushing it like this. Freddie is off for a service this month, so I'll keep you posted.

[Mrs Chippy]

I specifically asked the Honda dealer about this when we bought our 2.3hp 4 stroke. He assured us that it was unnecessary to flush. Has anyone had differing advice?
Agree about Magaret Dye's book BTW - a cracking good read with lots of useful advice. I'm afraid I don't have her fortitude though.

[Peter Cockerton]

Mrs Chippy

The Honda 2.3 is air cooled and as such does not have water travelling up the leg around an impeller and circulating around engine passages which get clogged up with salt. That is the main reason for flushing after being used in salt water.

Ps Sailing today in the middle of the UK winter were promised 10 kn of wind and possibly 14 degrees.

Peter

[Simon Holden]

One of my reasons for deciding on a Honda 2.3 four stroke was it's aircooling (no need to flush) and it being a four-stroke (no need to run dry) - evaporating unleaded doesn't leave any residue worth the name - surely nothing to gum up a curburettor?
After all do we run the car dry if not planning to use it for a couple of weeks?
Oops that was 2!

[Graham W]

Agree about Margaret Dye's book BTW - a cracking good read with lots of useful advice. I'm afraid I don't have her fortitude though.

Off topic, but Frank Dye's idea of a romantic honeymoon was to sail Margaret to St Kilda (way out in the Atlantic beyond the Hebrides) in his open Wayfarer.  Even large yachts think twice before doing that one. 

[Andy Dingle]

Simon et al..

You're probably right about running a four stroke dry after each use. After all, my lawn mower is never run dry, left over winter full of fuel and rarely even gets an oil change, yet starts each spring... I got the info from my outboard guru who mainly deals in monster 100 hp plus electonic fuel injected beasts, which he was probably referring to - even then he probably meant at the of the season. Not our little engines whose basic mechanics haven't changed for years. When he started on about ethanols in the fuel and how the lack of lead is destroying engines I sort of glazed over ... Being a complete mechanical numpty I tend to do everything I am told to do around outboards for fear of them conking out just when I need them most ,,,,

Re Frank and Margaret Dye, I just wanted to say I've had the pleasure of meeting them both.
I met Frank some years ago whilst I was on my Sea Witch 19 (remember them?) waiting for the tide at the yacht club (www.skegnessyachtclub.co.uk). On the flood a Wayfarer came up the creek sailed by an elderly gentleman, he asked if there were any free berths and I guided him behind me and took his lines. He then told me he had come across from Wells-next-the-Sea (about 25 miles across the mouth of The Wash!). I asked him aboard for a cup of tea and he introduced himself as the great man himself. I was astounded and we chatted for hours before the tide ebbed and he turned in, intending to get the early morning tide out and home. Kipping under his boom tent on his Wayfarer of course. A gentle, witty and self deprecating man. Incredibly knowledgeable and truly inspirational.
I met Margaret at various boat shows and she was equally charming and interesting. I still often think of her when I go to these posh boat shows amongst multi million pound gin palaces, and there was Margaret on her Wanderer dinghy amidst them all! I believe she too slept aboard during the shows, even inside at Earls Court! Great stuff.
Get her book if you want to know everything there is to know about living on board, or sailing a dinghy - or just want a good read!

Andy. BR20 'Psalter'