Outboard engine descaler

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NickC

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Is it possible to dissolve the salt/marine organism residue from our outboard water-ways with some sort of descaler?

It is a Johnson 6hp 4-stroke (Suzuki DF-6). I have removed the thermostat housing, scraped and flushed out as far as possible from there. It has a new impeller. Water does flow from the indicator jet but perhaps not as strong as I would hope to see. While running it in a fresh water barrel some salt crystals still get dislodged at times partially blocking the indicator jet. The rest of the waterways are obviously still partly clogged.

Is there a descaler that I can run through this to fully dissolve all the remaining residue?

Thanks,
Nick
 
NickC said:
Is it possible to dissolve the salt/marine organism residue from our outboard water-ways with some sort of descaler?

It is a Johnson 6hp 4-stroke (Suzuki DF-6). I have removed the thermostat housing, scraped and flushed out as far as possible from there. It has a new impeller. Water does flow from the indicator jet but perhaps not as strong as I would hope to see. While running it in a fresh water barrel some salt crystals still get dislodged at times partially blocking the indicator jet. The rest of the waterways are obviously still partly clogged.

Is there a descaler that I can run through this to fully dissolve all the remaining residue?

Thanks,
Nick
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There are products available for flushing out salt deposits, eg Salt-away, but dont know how effective they are or why necessary. Salt is soluble in water. Warm water ought to shift it quickly.

For descaling, if scale is the problem, "Rydlyme" may be the answer or an acid based general descaler or central heating boiler descaler eg Fernox DS-3.

But check it is not just the telltale blocked!.
 
NickC said:
This residue seems to be a combination of salt crystals and dead marine life. Very hard to remove, just soaking in fresh water doesn't seem to dissolve it much.
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Marine water residues can go rock hard - literally. I bought some salt away - really difficult to tell if it works or not. Even outboards that are flushed every time I suspect will accumulate some residues, as in the space of time between the engine stopping and you getting it home to flush it, it will cool down and crystals will form.

I have also heard of people flushing engines with a vinegar solution.

With small 2 strokes, removing the head and cleaning every couple of years could be relatively straight forward. I have not attempted it with a four stroke - but more complex I suspect!
 
Hi i use starbrite outboard descaler, if you can get some put it neat into your thermostat housing and also backflush some through your tell tale hole. If you already have some flow it should work. If you have no flow, forget it you need to strip down.Good stuff it does work and doesnt damage impellers or gaskets
 
steve66 said:
Hi i use starbrite outboard descaler, if you can get some put it neat into your thermostat housing and also backflush some through your tell tale hole. If you already have some flow it should work. If you have no flow, forget it you need to strip down.Good stuff it does work and doesnt damage impellers or gaskets
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Hydrochloric acid based I think you will find.
 
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remove prop stand in large bucket of cold water add about 1 litre of Rydlyme, start engine and run for 1 hour allow to cool repeat, that should dissolve any salts in the cooling system. (You will need to make a stand for OB) also the bleed pipe needs a bit of hose to return to the bucket. This stuff is good and DOES not your affect your skin, any splashes can be wiped off, unlike brick cleaner and acids.
 
pampas said:
remove prop stand in large bucket of cold water add about 1 litre of Rydlyme, start engine and run for 1 hour allow to cool repeat, that should dissolve any salts in the cooling system. (You will need to make a stand for OB) also the bleed pipe needs a bit of hose to return to the bucket. This stuff is good and DOES not your affect your skin, any splashes can be wiped off, unlike brick cleaner and acids.
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ITYWF that Rydlyme is also hydrochloric acid based
 
rbmatthews said:
The website for Rydlyme says that it is biodegradable. Is HCl actually biodegradable? What soaks up the chloride ions? Or is it a false claim?
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I'd think chloride ions would be just about the end of the biodegradable road for materials containing chlorine atoms in the molecule. Quite a lot of chloride ions in seawater already ITYWF.

The MSDS does not say it contains 5% HCl it actaully says < 10%.

Even at 10% it wont dissolve at much scale as they claim ( 2lbs of scale per US gallon) Do the arithmetic and see how much scale you make it for 1 US gallon of 10% HCl.

Also very vague about the pH !

Love to have been able to get some into the lab !
 
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rbmatthews said:
Yes, I see from the spec sheet... that it is 5% HCl, but I think that your stomach juices have only 0.5% HCl, so it is 10x more powerful...
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There is a lot of twaddle talked about such cleaning products being biodegradable, or not. Providing they are allowed to disperse they will become massively dilute, so they will do no harm.
 
Rydlyme might have been worth a try but I can't seem to find any suppliers in the UK and no cost listed anywhere.

After much research and a discussion with a friend who is a biochemist, it sounds like neat vinegar (acetic acid) might be both the safest most effective descaller available.

Next problem is where to buy an industrial quantity of raw vinegar, anyone have any ideas?
 
NickC said:
Rydlyme might have been worth a try but I can't seem to find any suppliers in the UK and no cost listed anywhere.

After much research and a discussion with a friend who is a biochemist, it sounds like neat vinegar (acetic acid) might be both the safest most effective descaller available.

Next problem is where to buy an industrial quantity of raw vinegar, anyone have any ideas?
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Vinegar is a dilute solution ( about 5%) of a fairly weak acid, acetic acid, pKa = 4.76.

Safe? certainly. Safest? possibly.

Most effective? Hardly! 1 litre of 5% acetic acid will dissolve , in theory, only 41.7 g of calcium carbonate scale and it will do so rather slowly compared with an equivalent concentration of a strong acid such as hydrochloric acid.

Cheapest ? Possibly even at around 50p per pint from supermarket
 
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stevebrassett said:
No costs, but here are some stockists in the UK.

http://www.rydlymemarine.co.uk/stockists.htm
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£9.95 per litre
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