Flushing outboard in an engine well

[coveman]

Has anyone devised a cunning plan for doing this? My boat lives on a swinging mooring in summer and the Yamaha 8hp 2stroke bolts into the engine well. I normally unbolt it and store it in the cabin when not in use and flush it with fresh water at the end of the season. More modern 4 strokes have flushing points to flush the engine in situ but the only way to flush mine is using muffs or the water access point at the bottom of the leg ( which is no use when in the well).
Could I tap into the engine somewhere or am I best to just flush at the end of the season? As an aside does anyone use the anti salt "Blu Thru"system?

 

[Fantasie 19]

Has anyone devised a cunning plan for doing this? My boat lives on a swinging mooring in summer and the Yamaha 8hp 2stroke bolts into the engine well. I normally unbolt it and store it in the cabin when not in use and flush it with fresh water at the end of the season. More modern 4 strokes have flushing points to flush the engine in situ but the only way to flush mine is using muffs or the water access point at the bottom of the leg ( which is no use when in the well).
Could I tap into the engine somewhere or am I best to just flush at the end of the season? As an aside does anyone use the anti salt "Blu Thru"system?

I do what you do... flush at the end of the season is all she gets... even if I could figure a way of doing it I don't carry more than four or five litres of fresh water anyway...

 

[Egbod]

Hi, I have the same problem.
To reduce corrosion at the gearbox / water-pump end I have tried squirting fresh water from an old detergent squeezy bottle into the water intake of the tipped up outboard. This was because a salty mush of partly dried seawater blocked the pump water intake.
I am considering making a spacer ring to hold the thermostat and the thermostat cover away from the engine. This can then have a hole drilled in the side to fit a small tap to to enable a tube to be attached and introduce some fresh water to the top of the engine for flushing.
Some outboards of the Mariner/Tohatsu family now come with a flush pipe that connects to the engine and allows a water hose to be fitted. When I replace my outboard I am tempted to get one with this feature and use it with a bottle of water when the engine is turned off.

 

[coveman]

Thanks for the replies - will certainly look into introducing a tap into the thermostat housing as you describe. It would seem a very sensible idea. Presumably it would be possible to force water up the "pee hole" but I imagine the flow would most likely be too small to have the desired effect.

 

[VicS]

Thanks for the replies - will certainly look into introducing a tap into the thermostat housing as you describe. It would seem a very sensible idea. Presumably it would be possible to force water up the "pee hole" but I imagine the flow would most likely be too small to have the desired effect.

Which side of the thermostat will you introduce the water.
It will be closed so water introduced "under" it so to speak will back flush part of the cooling system and the water intake, most probably exiting via the telltale. Water introduced "above" it will flush the other part of the system, which may only be the cylinder heads, and exit via the "leg" and the exhaust outlet. Exactly what happens will depend on the make and the design of the cooling system

 

[Egbod]

VicS, you are correct. I have yet to check which is the best side of the thermostat to flush. Are all outboard thermostats arranged the same way? Perhaps there is space for 2 spacers and then you can flush both sides in turn with a little fresh water. Anything must be better than leaving salt water in an engine to dry out and encourage corrosion.
Geoff Theed, this problem doesn't just affect boats with an outboard well but all boats with an outboard on a mooring/berth without fresh water.

My preferred solution would be an "air cooled" engine with a closed cooling system linking the engine coolant system to the gearbox. Then pump oil around the whole system. The oil would be cooled as it passed through the gearbox surrounded by cool seawater. Hopefully this would result in no salt build up and little corrosion. ( some water may have to be added to the exhaust system to cool it).

 

[seumask]

We had the same Yamaha 8 2stroke in a well on our boat on a swinging mooring for 5 years, and all it got was the end of season flush, and servicing of the water pump every 2 years. Assuming your not running mud through it I suspect it will be fine. My thoughts were to ensure the engine was running cool when stopped each time as its the boiling off in the cooling jackets that really builds up the salt, i.e. let it idle for a couple of minutes before you switch it off.
I took the plate off the cooling jackets to see how much salt had built up one year and there was very little to scrape out. Make sure you get replacement gaskets before you do this relatively simple operation.
I like this engine which was very reliable for us and easy to work on and service.

 

[Poey50]

Has anyone devised a cunning plan for doing this?

Geoff - as you remove it at the end of each trip (for security reasons and to avoid the need to antifoul) would it be possible simply to place the leg in a bucket of freshwater - perhaps taking the weight from above on the boom - once you have lifted the engine? I know Vyv Cox straps an opened fender to the leg of his (smaller) outboard to flush. David

 

[coveman]

Thanks for the replies and some very valid points. I am probably being over cautious as most seem to just flush at the end of the season, as #7 suggests. Certainly worth leaving the engine to idle for a while before stopping it.
David - good to hear from you - will have to see if I can rig some sort of contraption, as it should be possible to flush it in a bucket or tub even if it was only done periodically. It probably makes little difference but it makes you feel good afterwards! The engine has been very reliable starting 1st or 2nd pull. Geoff

 

[Poey50]

David - good to hear from you - will have to see if I can rig some sort of contraption, as it should be possible to flush it in a bucket or tub even if it was only done periodically. It probably makes little difference but it makes you feel good afterwards! The engine has been very reliable starting 1st or 2nd pull. Geoff

Poppy only had two complete seasons on a mooring - prior to that the engine was flushed religiously after every trail-sail. That's because the original 6hp engine that came with the boat was never flushed by the previous owner and eventually died so I was determined for that never to happen again. Hopefully you should get plenty of trouble-free years. They are good engines.

 

[coveman]

Poppy only had two complete seasons on a mooring - prior to that the engine was flushed religiously after every trail-sail. That's because the original 6hp engine that came with the boat was never flushed by the previous owner and eventually died so I was determined for that never to happen again. Hopefully you should get plenty of trouble-free years. They are good engines.

That's interesting David. They are certainly good engines - Robin Curnow, the Yamaha dealer in Falmouth swears by them and at 27kg are a lot less weight to lug about than a 4 stroke. I will definitely persevere with your idea of rigging something up so it can be flushed on the boat - it makes good sense if it is possible. No problem with flushing on a Sadler at least not with the engine!! Geoff

 

[Greenheart]

The bucket idea struck me, when this question was asked in a thread here, late last year.

I described what I was imagining, but nobody ever replied, so I assumed the idea was beneath contempt.

The cut fender sounds brilliant...flexible enough to shove down a slender well, and it even has a tough loop in the top for a lanyard.

Presumably any engine other than the very smallest or most primitive, can be placed in neutral and run with ten litres of fresh water in the fender, thoroughly flushing out the brine, or diluting it to a point where it doesn't matter...

...more to the point, is there anything to prevent the flushing water then being pumped out of the fender, leaving the still-down, previously immersed engine leg, dry? It wouldn't be beyond even my small skill to make a cowl to prevent rainwater filling the fender in the time before I returned.

Seems to me, several excellent small yachts are based around an outboard in a well, and some of them don't allow it to tilt...

...is there any good reason not to leave it down, kept dry and safe from salt and barnacles, by the thick rubber of an old fender?

 

[coveman]

I'm not sure I would want to leave the outboard in the well permanently, which I think is your suggestion
From a security point of view I like to lock it away in the cabin, but I guess the decision on this depends where you keep your boat.
I am looking into making a frame so that the outboard is raised in the well ( it can't tilt on my boat ) and then use a container of similar size to the well, which could contain ,say 10-20 litres of fresh water to flush with. The container could be rigid or a flexible bag would be easier to stow. By using the well like this it should not be necessary to raise the engine very high. Now to the drawing board .......!
The frame needs to be simple so that the job is easy and quick to do.

 

[Fantasie 19]

I'm not sure I would want to leave the outboard in the well permanently, which I think is your suggestion
From a security point of view I like to lock it away in the cabin, but I guess the decision on this depends where you keep your boat.
I am looking into making a frame so that the outboard is raised in the well ( it can't tilt on my boat ) and then use a container of similar size to the well, which could contain ,say 10-20 litres of fresh water to flush with. The container could be rigid or a flexible bag would be easier to stow. By using the well like this it should not be necessary to raise the engine very high. Now to the drawing board .......!
The frame needs to be simple so that the job is easy and quick to do.

This issue then becomes getting 10-20 litres of fresh water to your boat every time you go sailing..??

 

[Greenheart]

Is a few gallons of water so problematic an addition to the stores of a small yacht, Fantasie? I usually have a couple of litres on the Osprey, just for drinking.

Geoff, I had thought that avoiding having to move the engine would be ideal. Plenty of outboards are left on brackets, tilted up, but open to general observation and the elements. The necessity to devise a rugged but operable sliding bracket sounds like wilful self-immersion in a long programme of garden-shed engineering! Of which I strongly approve, but is that the best solution?

I can imagine the threat of crime driving me to many extremes, but isolating the outboard leg from the sea without moving the engine from a secure well, is very appealing to me...it would also allow a bigger outboard to be used, because it wouldn't need to be easily movable...yet could still be frequently, thoroughly flushed and stored bone dry.

 

[coveman]

Dan,
Yes I would agree with you - anything for an easy life! The problem I have is that the engine leg is surrounded by a rubber bung ( for want of a better word! ) that exactly fits the bottom of the well and this would have to be removed each time, in order to position the cut fender under the prop etc . The engine would have to be lifted to do this. Unfortunately the only way I can think of doing it is to lift the engine slightly so I can leave the bung intact around the engine and then immerse it in a bin ( a small refuse bin seems a good candidate and holds 25ltr when full ).

 

[Greenheart]

I understand. But, is it necessary to keep the rubber bung - which I assume keeps the undersides smooth under sail - in position, when neither yacht nor engine are in use? If you could haul up the bung, you could poke the fender down the well with a broom-handle...

...and pull it round the engine leg with the lanyard...then pour in a three-gallon bucket of fresh and start her up.

I realise my enthusiasm probably doesn't grasp the difficulties of your particular case, but I'm excited...Vyv Cox's solution has persuaded me that a yacht which I thought I didn't want, is now much more attractive, because the 40kg 10hp outboard could live in its well without having to move from one year to the next. Granted, it would need a big fender! Here's the link to Vyv's article...

http://coxeng.co.uk/cruising/outboard-motor-fresh-water-flush/

 

[coveman]

Thanks for the link and yes its a great idea. No, the bung would not be necessary while the engine and yacht are not in use, but the only way the bung can be removed is by lifting the engine which is rather frustrating.
I have sailed the boat without the bung or engine in place and there is surprisingly little turbulence in the well and I have a small 2.5hp 2 stroke which I could use just to get on and off the mooring, when necessary, and the "fender flush" would be ideal for that.
The Etap is designed so the engine is bolted down on two rubber pads with the normal clamp arrangement removed, which makes life a bit more complicated.

 

[wombat88]

The thing that has yet to be solved is the matter of a heavyish outboard sitting in a well with the bottom end submerged and an owner like me who doesn't enjoy lifting it out.

How long will it last?

I've got a lump of wood across cockpit lockers that allows the engine to be raised vertically until it clears the water (still a bit of a hassle). This keeps it just out of the salt but of course negates the use of 'an approved lock' for insurance purposes. At least I don't have to drag the thing around the boat.

The idea of wrangling a bag round the leg with the engine in position and then the filling it with fresh water for flushing or leaving it dry for storage sounds fine in theory but probably not great fun in practice.

If I could convince myself that outboard were disposable perhaps I wouldn't really care...

 

[Greenheart]

The thing that has yet to be solved is the matter of a heavyish outboard sitting in a well with the bottom end submerged and an owner like me who doesn't enjoy lifting it out. How long will it last?

The idea of wrangling a bag round the leg with the engine in position and then the filling it with fresh water for flushing or leaving it dry for storage sounds fine in theory but probably not great fun in practice.

Despite the respect I feel towards you Wombat (and I mean that...you often say exactly what I'm thinking), I'm baffled by your doubts. You first present the very essence of the problem...then dismiss an excellent solution to it.

The key here seems to me to be Vyv Cox's cleverness in choosing a guillotined fender, which is neither stiff and awkward like a plastic bucket, nor floppy and prone to breakage like polythene. So 'wrangling a bag', as you put it, doesn't seem to be fair comment.

An oar inside the fender pushes it below the prop; then a lanyard pulls it up round the leg, securing the top above the waterline.

30 seconds with a stirrup pump empties the brine from the fender...and then, which of us isn't capable of rigging up a syphon to empty a jerrycan of fresh, into the fender around the outboard leg? Engine in neutral to flush out the salt, then pump the fender dry.

The beauty of it is the economical availability of everything required; plus the option to leave the engine in its 'down' position.

Looks to me like an eminently practical boat-owning technique. Have I missed some critical difficulty?

...the only way the bung can be removed is by lifting the engine which is rather frustrating.
I have sailed the boat without the bung or engine in place and there is surprisingly little turbulence in the well.

Seriously, I'd be tempted to fabricate a two-part bung, from stiff closed-cell foam, rather larger than the aperture, so the foam is compressed in use and stays in place. The halves could be hauled up out of the well much more easily than a single piece. Maybe the foam around the leg would need some defending against exhaust heat? But that can't be beyond science and ingenuity.