Flush Raw Water System

I would like to acid flush the raw water systems of my Cat 3208 engines. Does muriatic acid mixed 15 to 1 with fresh water make a good flushing chemical. The commercial flushes seem expensive.

Barnacle Buster is about $80/gal and makes 5 gal after mixing with water. Works great, but I'm sure someone can chime in with a 'homemade' version that works also, using the same chemicals.

I use BB also, worked great.

I'm a Barnacle Buster believer also. I put the mix in a 5 gallon bucket then circulate it though the system with a cheap bilge pump. Be sure to remove any engine / cooler zincs when using it.

I worked in the chemical cleaning industry early in my career. We used a 30% solution of muriatic acid in water for dissolving heavy water scale on heat exchanger tubes, the same thing at work in your raw water system. That dilution gives you a solution that is about 10% HCl by weight as commercial muriatic acid is about 32%.


We found that scale dissolving capability dies off at about 5% HCl by weight or about 6 parts water to 1 of acid.


So 15:1 is way too low.

Barnacle Buster is based on phosphoric acid I think. It doesn't produce the same irritating fumes that muriatic acid does, but it doesn't work as well. But it seems to work well enough.

David

I started flushing the raw water system with fresh water after every use. My hope is that it will reduce the buildup of deposits and rust.

Another voter for Barnacle Buster here- worked wonders on my 3208TAs.

Our engines get flushed with fresh water during the 2 hour trip from the locks to our slip in Lake Washington. This winter I will be removing and checking the heat exchangers, oil coolers, exhaust elbows, and aftercoolers for the first time in their life after 17 years and 2000 engine hours. I'll report on what I find.

My cooling system (raw water side) was completely "cleaned" off the engine in early 2017. Just today, I replaced my gear oil cooler with a new one that has zincs (the old one does not). The saltwater side of my old gear cooler was "spotless", however, I freshwater flush my engine as often as I can, and store the engine with a solution of "salt away" inside for the winter. I have an oil pan heater that runs throughout the winter and freezing temps are rare here in southern (coastal) BC.
I am a big believer in the benefits of freshwater flushing, and it only takes about 10 minutes to do it.
Tom

$29 for a gallon of Barnical Buster or $135 for a kit with descaler solution.


https://www.amazon.com/Barnacle-Bus...c26174ff6a9ba943fead7b8549131d&language=en_US




https://www.amazon.com/Mainstream-M...dd4b9e5f6cffcec9437fce375b173a&language=en_US

I did a Barnacle Buster recirculating flush of my engine several years ago. It did a good job, and it's much cheaper than Rydlyme. For the last couple of years I've been using a product called "Acid Magic". It's a buffered (no skin irritation) muriatic acid product used for cleaning pools. Costs about $10 per gallon. I've been up in a fresh water river slip for the last several years, so I end up doing a fresh water flush coming and going. Now as part of winterization, I pour in a 10:1 solution of Acid Magic into raw water side, let it sit for an hour or so, then flush with 6 gallons of fresh water and a box of baking soda to neutraize any acid, followed by a fresh water flush. Don't forget to plug you're raw water hose going into any dripless shaft seal. Any acid MAY cause damage to the bellows. After 14 seasons, I had a leaking gasket on my Cummins 6BTA heat exchanger. Replaced the end cap and gasket this year and interior of heat exchanger was perfectly clean.

As David said, 15:1 is a weak enough ratio to be pretty much ineffective. He knows chemical stuff.

Muriatic acid is "old school" and was the solution to use for years. I've seen a couple of times where, used wrong, it can actually damage thinner metals. Makes me leary of the stuff.

Barnacle Buster is Phosphoric acid with a couple of other non-corrosive chemicals added in. It dissolves organic matter without damaging metal or rubber. Instead of paying $80 per gallon for Barnacle Buster, I go to Home Depot and pick up a gallon of phosphoric acid in the paint department for about $17. I fill a 5 gal bucket about half full and pour in the acid. It's a little stronger than the recommended mix of BB but it does the trick very nicely on our engines, generator, and a/c units.

John

I haven't done this before and would love to see pics of your setups, adapters for tapping into the cooling systems hoses and such. Heck, bonus if you have Cat 3196 mains? Thanks

Here are a couple of pics of the setup to circulate Barnacle Buster through the raw water system of a Yanmar 6LY.

The first is the bucket with the hose to the injection elbow pulled off and stuck in the bucket. There is a small bilge pump in the bucket which discharges to the clear braided hose in the picture. The hose taped to the injection elbow is a water hose to supply water to it so I could run the engine periodically to keep it warm. Outside temps when I did this were in the mid 40s.

The second pic is of the discharge hose connected to the outlet hose from the removed raw water pump using pvc fittings. Note the mounting place for the pump is blanked off so I could run the engine and not get oil all over the place.

Other engines can be done more or less the same way. If it isn't easy to get to the raw water pump discharge, then remove the impeller, reinstall the outer plate and hook up to the raw water supply hose from the strainer. Make sure and clamp off any raw water hose to the prop shaft gland and remove all zincs and reinstall the brass plugs.

David

Thanks!


Why do you need to clamp off the prop shaft gland, is the flushing fluid bad for the gland?


Btw I like your fresh water adaptor to the top of your raw water strainer.

w8n4sun said:

Why do you need to clamp off the prop shaft gland, is the flushing fluid bad for the gland?

Click to expand...

If you mean the dripless shaft seal hose, it's because the "product" (BB, Rydlyme, whatever) disappears overboard out through the shaft seals if used in a recirculating process.

-Chris

D'oh, that was a dumb question!

It is a PITA to remove my impellers to recirculate the BB so I used a Sea Flush to suck the BB into the engine through the strainer. When the 5 gallons has been sucked in I shut down the engine and let it sit for about 7 hours then start the engine and flush the BB out the exhaust. My engine temps dropped 5 degrees on one engine and 10 degrees on the other engine. Doing it this way takes about 5 minutes to get the BB into the engine.

Comodave said:

It is a PITA to remove my impellers to recirculate the BB so I used a Sea Flush to suck the BB into the engine through the strainer. When the 5 gallons has been sucked in I shut down the engine and let it sit for about 7 hours then start the engine and flush the BB out the exhaust. My engine temps dropped 5 degrees on one engine and 10 degrees on the other engine. Doing it this way takes about 5 minutes to get the BB into the engine.

Click to expand...

My impellers are easy to get to and I still use the Sea Flush approach. So darned convenient!

Yes, the Sea Flush is definitely a great system. I am getting ready to use mine to winterize my engines hopefully on Thursday if the yard gets the other boats in the barn so we can go in last. No affiliation just a really satisfied customer.

The fill and soak method works but not as well as continuous circulation. Circulation brings fresh acid to the site of the scale and removes insoluble organic matter that gets in the way.


In my early career we only used fill and soak on huge central station power boilers. Those never had thick scale, just a lot of it due to their size and fill and soak worked fine.



David

w8n4sun said:

D'oh, that was a dumb question!

Click to expand...

Not so dumb. You can guess how I learned that answer.



-Chris

djmarchand said:

The fill and soak method works but not as well as continuous circulation. Circulation brings fresh acid to the site of the scale and removes insoluble organic matter that gets in the way.


In my early career we only used fill and soak on huge central station power boilers. Those never had thick scale, just a lot of it due to their size and fill and soak worked fine.



David

Click to expand...

Yes the recirculating method is better, but if I have to pull my impellers in order to do it that way, I won’t do it. So I can literally do it in 5 minutes per engine with the soak method then I will do it. I did see positive results from the soak method.

MV Wanderlust said:

...Instead of paying $80 per gallon for Barnacle Buster, I go to Home Depot and pick up a gallon of phosphoric acid in the paint department for about $17.

Click to expand...

Look carefully at the % of phosphoric acid in those HD cleaners. Could be 25% or less. You can buy a gallon of 85% phosphoric acid on Amazon for $40. Still a fraction of the cost of BB and a gallon goes a LONG way if you dilute it to the same concentration as BB.

hey neighbor!

Hey, I know you!

Newbie question here... I have always had by boat "flushed" after going through the locks here in Seattle. Now I am in the salt. This doesnt strike me as an annual flush maintenance item... or is it? This sounds more like a eery 3rd year deal. Trying to figure out if I need another homemade maintenance set for my wife to complain about. ha!

emilanderson said:

Newbie question here... I have always had by boat "flushed" after going through the locks here in Seattle. Now I am in the salt. This doesnt strike me as an annual flush maintenance item... or is it? This sounds more like a eery 3rd year deal. Trying to figure out if I need another homemade maintenance set for my wife to complain about. ha!

Click to expand...

Two things that cause issues are salt build up and marine growth. I'm sure there are others. Depending on how much you use your boat and how fast salt and marine growth builds up, it could be years. Down here in the south east boats need cleaning quite frequently to keep growth off. Monthly at least. I would do a barnacle buster type product at least every spring and maybe again in the late fall, but this is for my area. Your area maybe vastly different.

dhays said:

I started flushing the raw water system with fresh water after every use. My hope is that it will reduce the buildup of deposits and rust.

Click to expand...

The previous owner and I did just that, and three years after I bought the boat, I had a hose burst just downstream of the raw water pump. A BB flush put all kinds of coloration in the bucket. Maybe FW flushing helped, but it certainly did not eliminate it. I will be flushing at least every two years.

Freshwater flushing (as often as possible - after every use is "best") will delay the need for removing all saltwater based cooling items for servicing. If you have an aftercooler, it should be serviced every 2-3 years (off the engine) if you don't FW flush. This off the engine servicing entails: removal of fuel cooler, gear oil cooler, aftercooler, and heat exchanger; acid cleaning of the saltwater side; pressure testing; proper reassembly of the items (especially the aftercooler - new O rings, everything well greased to reduce future corrosion); reinstallation of the previous items; and new coolant.
Just running BB through will not ensure that "all is well" for the long term. All of these items can be subject to "failure" where leaking can occur possibly resulting in raw water in your transmission, or raw water in the coolant, or raw water in the air side of your engine. Pressure testing should find problems before they can cause "real issues". Also, the air side of the aftercooler is not touched at all by the BB solution, and it needs cleaned as well or your engine can become "air starved".

Not saying that BB (or flushing with other products) is a bad idea, just trying to "look at the whole picture".
Tom

porman said:

Our engines get flushed with fresh water during the 2 hour trip from the locks to our slip in Lake Washington. This winter I will be removing and checking the heat exchangers, oil coolers, exhaust elbows, and aftercoolers for the first time in their life after 17 years and 2000 engine hours. I'll report on what I find.

Click to expand...

Keep in mind, fresh water will cause a coating to form on zinc anodes, essentially rendering them inert. The coating can be cleaned off using a ScotchBrite pad, however that requires removal of pencil anodes, at which point you might simply chose to replace it unless it's like new. Hull anodes can of course be cleaned by a diver. Until cleaned their effectiveness will be diminished. Alternatively, you can use aluminum anodes, whcih are immune to this phenomenon.

More on the subject here https://stevedmarineconsulting.com/galvanic-isolators-and-zinc-anode-selection/