Cleaning Outboard Cooling Water Passages

In this video I experiment with cleaning the cooling passages in three outboard heads using different chemicals. I try using Salt Away, Hydrchloric acid (muriatic acid) and white vinegar.

Dangar Marine

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Cleaning Outboard Cooling Water Passages – Video Transcript

Hey there, Dangar Stu here. Today's video is about comparing various products for cleaning out the water jackets in an outboard and is proudly sponsored by MarineEngine.com.

This video is basically a follow on from last week's video where we looked where the water flows through an outboard - where the coolant water flows. And a lot of people commented in that video asking what you would use to clear the salt away from the water jackets. I've never really done a lot of flushing of outboards other than running it on the muffs here just on fresh water. Because the boats we use on the island live in the water all the time, it's very difficult to get them anywhere to flush them. So, I'm kind of interested myself to see what these products do. Will they make any difference at all or whether fresh water really is just the way to go.

Before we get going though I've received another viewer t-shirt photo. This one's pretty funny. This is Ron here in Smith Creek, which is a local waterway to the Hawkesbury. And he's got his dog there Rex next to him. Apparently the t-shirt actually belongs to his wife, but she was a bit shy to be in the photo so Rex got in instead. Alright so we'll pop Ron and Rex up on the board and we'll get into it. Oh and I always forget to say the link to buy t-shirts is in the description of each video. They're actually printed in Europe and the US now depending on which printing center is closer to you, but the prices in Australian dollars they're actually cheaper than most people think if you're converting to a different currency that's all.

So, the three things I'm going to try today is straight white Vinegar, hydrochloric acid, which I'll dilute, and salt away, which is kind of a commercial product specifically for this purpose. I'm not going to be flushing an outboard. Because it's going to be hard to sort of look at it, take it apart, flush it, test it, etc. So, I'm just gonna be soaking some bits in it. It's not really representative of what a flush would do, but I just thought it's a way to compare the results. I'm going to use the block we looked at last week in the cooling video, so I'm just going to be soaking it. I think I'll decide on about an hour's soaking. I'm not sure whether that's going to be better or worse than say 10 minutes of running with the water moving a lot, but I think it'll just give us some sense of what these chemicals do. Before we get going I've got to say hydrochloric acid can be a little bit hard on aluminum. So, I'm not necessarily going to be advocating any of these things. Even if it gets it looking amazingly clean, which it may do, it doesn't necessarily mean it's the best thing to use. Just be interesting to see what the results are. It's more of an experiment really. I'm also going to grab an impeller and I'm going to put an impeller in as well. Just to see what affect it has on the rubber of the impeller. I think that's kind of a critical part of it. Might get the middle really clean, but dissolve an impeller or something. So, I think it's worth knowing that as well.

I've got three tubs with 10 liters of water in each now. So, I'll just add a recommended ratio of product to each one and then we'll get them soaking. So, for the hydrochloric acid, it actually says that 10 to one is kind of what it recommends for cleaning brickwork and stuff. Maybe that's a bit much for this. I really don't want to cook this element in too much. I mean it's all scrap metal now so I don't really care what the results are. But can't say I'm confident on what I would ultimately put through a functioning outboard. Probably nothing because I don't know if I take the risk, but let's have a look. If it's saying 10 to 1 for cleaning up brickwork and stuff; I think I'm going to go 20 to 1. If nothing else, it will give us one data point to say was it too much, was it too little, whatever. So, in that case, 10 liters here. I'm just going to put 1/2 liter in. Be careful with hydrochloric acid it can burn you and the fumes are actually quite sort of caustic as well so I'll hold my breath. It's also worth noting with the acid that it's sometimes called muriatic acid. Depends where you buy it. So, it's either hydrochloric or muriatic. It's pretty much the same thing. This is the one I'm going to put into the acid. It's probably the worst one so interesting to see how it goes. I'll dump it in later so we put them in all at the same time.

Once again, with the vinegar, it's a little bit of a guess. I think you could easily put a hundred percent vinegar on a head like this, but it would be very difficult to flush a motor with that kind of concentration. You just couldn't get enough of it. So, I'm just going to tip the hole liter in so we're going to have 1 to 20 for the acid and I'm going to have 1 to 10 for vinegar. On the salt-away packet it says that for immersion applications go for 1.5 percent. So, I'm going to put 150 mils into this 10 liters of water. The head I'm putting in the vinegar is this one. Just so you can compare the two as well. And this is the one I'm putting in the salt-away. So, we'll dunk them all in their respective containers and we'll give them half an hour for now. Glad the clocks working. I'll give you a look what's going on. Other than the acids are bubbling away, not much has really changed with the other ones. That's probably due to the fact that it's sort of sitting still. So I might sort of give them a bit of a shake, let them sit for another half hour. After that, I might also give them a bit of a brush just to see whether the solution sort of softened it up at all. I'll give you a quick look what's Happening. I also forgot I'm going to dump an impeller into the acid one. I'm pretty sure the vinegar is not gonna do any harm and the salt-away is obviously designed for this purpose. So, I'm not expecting any damage there. So, I'll pop this impeller into the acid. I'll give you a quick look what they look like now and then we'll wait on the half hour. I'll also give them a bit of a stir up and then we'll pull them out. Maybe hose them off and then see what we see. S

o this is the one in the acid sort of bubbling away a little bit. This is the vinegar which hasn't really done much at all. And this is the salt away which is blue. Can't tell you much more than that. Anyway we'll let them go for a half hour and then we'll give them a rinse off. Predictably I got a bit distracted and it's now probably about an hour later. So instead they've been in for about an hour and a half all up. So what I'm going to do is just, once again, I'll show you what each one looks like. Then I'll give it a bit of a brush while it's in the solution. See how it comes up. Then we'll go and hose them off. This one's hydrochloric acid and its certainly got the most debris floating around in the solution. Here's our impeller. It doesn't seem to have suffered at all from being in the acid. So that's good. That's something we know now. I presume then if it had a good run with fresh water afterwards it would be fine. So, I'm going to put the camera down and just do- see even if I shake this a little bit. Must admit this hasn't done a bad job to be honest with you. So I'm going to give it about three minutes brushing with each one and then we'll see what it looks like. So, this one came out pretty well. Not seeing any signs of damage from the acid. It's certainly pretty clean now. So I'll just give that a quick rinse with fresh now and leave it aside.

So, just to note, this actually had a thermostat gasket stuck to it and it still looks pretty healthy too. This next one is the vinegar, which doesn't seem to have done much at all. But I'll give it a brush and see what happens. Once again, after bit of scrubbing, came pretty clean. But feel like it was the brush that did all the work to be honest with you. So, here's the salt-away one. There's no real debris in the tub. If you look in here, though, it's got similar mud. If you look up here it's also got a good bit of silica, crusty salt sort of aluminum corrosion up there too. So, I'll give this one a brush and see how it compares to the other ones. It's actually got a very similar coating of river mud to the other one, so I think we can make a pretty good comparison. So straight out of the salt away after a soak. This has still got quite a bit of mud on it that's for sure. Some of these sections, like here hopefully you can see, look quite gritty like it's a bit more salt or something. So, I'll give this one a light brush and we'll see how it goes.

Yeah, you know, I gave it a bit of a scrub and the bulk of it came off. It did feel like it was mostly just the brush doing the work, but I would say it was noticeably better than the vinegar. I'll just show you quickly as well. This is the salt away tub after I started doing a bit of brushing. So, it's obviously got some sort of detergent that, with a bit of agitation, sort of foams up as well. Which is interesting to see. I'm not sure what conclusions we can really draw from this rather unscientific experiment, but I guess there's a few things I learned. So I certainly never really used any of these things to try and clean an outboard before. I guess in doing this comparison we also have to look at what we're trying to clean off, which is mostly a sort of a salty aluminum corrosion and a lot of river mud. The water that these boats drive in is very salty and has a lot of silt in it, so I think that's really what builds up over time. I think we can kind of say that vinegar doesn't really do a lot for either. It took a fair bit of sort of scrubbing to get the mud off and you know I think water would have done pretty close to the same job. The salt- away was interesting in that; yeah I think it did do a better job than the vinegar.

I think it was better than just water. But at the end of the day, I think its job is to flush out a bit of remnants of salt if you're in reasonably clean ocean water. Say, for example, at the end of each day. I think by the time a motor has been run in silty, salty water for ten years, like this outboard probably was, I think it's kind of beyond the scope of what that products designed to do. I've got to say that when it comes to flushing a motor every day, I think if you're looking at just getting mud that hasn't set yet or dried yet and salt out. You're miles ahead of the game if you just do a freshwater flush at the end of the day anyway. You're probably better off with some sort of product. And certainly one other advantage to salt-away is the product is designed to be picked up at a very low concentration by a venturi and fitting. So, from a practicality point of view of flushing it kind of wins in that department too.

But don't expect it to unblock a motor that's already got to the stage where the cooling passage is really blocked. I don't know. I'm certainly not seeing it here. Once again it is designed to run through to have that water circulating. So maybe it was circulating and running for quite a while might be different result, but I can't say either way. So this particular cylinder head that we put in the acid was by far the worst and it actually looks quite serviceable now you know. Just to sort of refresh your memory those galleries are actually quite clear now. You know in the extensive two minutes of research I did before filming this video, there were a few people who were very concerned about acid really damaging the structure of the aluminum and weakening it in some way or whatever. I don't know. It kind of sounds a bit alarmist to me given this seems fine.

But am I saying you should run out and go and put hydrochloric acid through your brand new outboard, no. You know I don't know enough about it to recommend it. But if I had an old outboard that was so blocked it kept overheating and I didn't have any other option I think it'd be something I'd try. Particularly interesting to see no damage at all to gaskets, impellers or anything from that twenty to one mix of hydrochloric acid. And it was in there for an hour and a Half. So, you know, I'm not seeing any collateral damage that would worry me. I did notice it was bubbling a lot from the cleaner sections like the threads for the spark plugs, but they actually still look pretty good too. So, I'm not seeing anything would really worry me. But, as I was saying, it's not a particularly extensive test and it's certainly not particularly scientific. So, take with a grain of salt. If you excuse the pun. Alright well thanks for watching.

Really this was obviously just a bit of a follow up to last week. To answer a few questions on what can you do about this sort of corrosion and I certainly didn't know the answer so I was quite keen to do experimenting myself. So, the end result is if you're looking to flush an outboard after every trip, use either fresh water or put a bit of salt away in it. And if you're looking to restore an outboard that is really corroded up over time; I'd recommend the acid, but just be careful. Obviously gloves, glasses that kind of thing because even at 20 to 1 it still can burn skin and you can get fumes inhaling and all that kind of stuff. So make sure you've also got really good ventilation. Alright, well take care and I'll catch you next week.