Engine Flush

[Hookshurt]

Is there any chemical that is Coast Guard, I mean eco friendly that can be run through a raw water cooled engine to clean scale, rust, and all the other nastys that like to call themselves home in the cooling system? I flush with fresh water each time I run them, but from the looks of the risers I just replaced, that ain't cutting the mustard. Thanks

[CaptPatrick]

Muriatic acid, the swimining pool stuff... Fairly weak acid, will dilute into the bay water rapidly. About as eco friendly as can still get the job done.

Br,

Patrick

[Hookshurt]

Thanks Capt. I thought about the idea of using a measured dilution system. Like what you would use for spraying fertililzer or weed killer on your lawn. Would that be the best means to introduce the chemical if I modified the "sprayer" to work in line as I suppose I'd need to start the motor to incorporate whatever chemical I used into the motor? Does the acid need to sit in the motor for a long period of time, how strong a solution would it take, and how will the acid affect the cork gaskets on the strainer baskets? Am I pushing my luck yet? Thanks again!

[Charlie J]

ive heard people putting in a clorine tablet thats used for swimming pools. they put it in there raw water strainer and let it disolve

[hubris 1]

ive heard people putting in a clorine tablet thats used for swimming pools. they put it in there raw water strainer and let it disolve

does that work? great idea.......somehow I think it cant be this easy. But I like the way you think!

[Hookshurt]

I thought it was a great idea too! I'm not sure about your strainers, but mine open when I loosen two wing nuts. Shouldn't be much more work or complication than throwing tabs in a a pool system. Wait...as easy a time as I've had on everything else on the beast...I suspect they don't make a tab that will fit in the strainer basket.

[hubris 1]

I thought it was a great idea too! I'm not sure about your strainers, but mine open when I loosen two wing nuts. Shouldn't be much more work or complication than throwing tabs in a a pool system. Wait...as easy a time as I've had on everything else on the beast...I suspect they don't make a tab that will fit in the strainer basket.

LMAO! I bet your right. take a bite out of it..............argh,

[CaptPatrick]

Chlorine isn't going to do anything but kill germs.

Organic scale and calcium build up has to be removed either mechanically or with acid. Muriatic acid is a hydrochloric acid solution and, as with all acids, common sense and precaution are essential. That includes proper dress, rubber gloves and full eye protection. Have a large box of baking soda on hand in case of a spill or splash.

Commonly called boiling out, the acid must fill the system or individual item, and must not be capped off. The reaction between the acid and calcium, (a base), will cause gasses to be formed. A capped system will build pressure.

The muriatic acid needs to work for several minutes before rinsing out the system or part.

Some other acids and acid mixes will also work, but most are more expensive than muriatic and may take longer to get the job done. Alspho will work and CLR will work.

All of this takes place only on the raw water side of the exchanger system. Not the fresh water side. Usually there is no gasketing on the raw water side since it is a non-pressurized system. The only gasket would be at the water pump. The acid will only be contacting the inner edge of the gasket and for a short period of time, so little or no gasket damage will occur.

The exchange core is copper and the outer shell is iron or steel. It would take hours for the muriatic acid to eat through any metal, unless the exhangers are very old and already corroded from improper bonding. Rubber impellers will not be affected.

Mix one part muriatic acid to two parts water. Afterward, reverse flush the system using air pressure to blow hot water through the plumbing in the opposite direction of its normal flow.

You can flush the system directly overboard, or if you feel the need to be Green, the acid can be collected, (for the most part), via the hose from the raw water system that finally dumps into the exhaust, and disposed of after neutralizing with baking soda.

There are flush additives that will reduce salt, but they do nothing to stop future scale build up. Boiling out is just one of those routine, but infrequent, maintenance items.

.

[Charlie]

I flush my 3208Cats every two years with straight muratic acid. I remove the zinc on the raw water side an PUMP one gallon in. Make sure you do not the stuff on anything except the inside of your exchanger! Let it sit for 15 min. and start the motor. I do both and take the boat for a nice run getting up to operating temp. To avoid any spillage I have rigged up a bucket that I pour the acid in and after the 15 min I chase the acid with a couple gallon of water. Be careful, the fumes will burn you nose and eyes. After all it is HCL hydrochloric acid.

[randall]

when i had my abalone boat in santa barbara harbor it started to run a bit warm so i gave it the muriatic acid flush. a bright green plume started trailin off from the stern down my slip row. i look up and the harbor master is lookin at me "um, son............"

might be eco friendly but not invisible

[Capt Dick Dean]

Before my Bertram life began, I use to fill up my heat exchanger with muric acid and let it sit 15 minutes. To do this I took the exchanger off the engine, took off one end plate, put the thing up right and filled it up. Viola! It worked great This application was on an I/O. This is how I got the Bertram. Dam little I/O ran poorly. Told my wife,"We need a better boat. A 30 footer."

[Glen Snader]

I would not use the chlorine tablets. In fact they are calcium hyprochloride. They will put calcium into your system. This will vary depending on the water PH and minerials in the water + hardness. Also, chlorine is corrosive. It will not do the cast iron manifolds any good over the long haul. Acid works great and it is cheep. Be careful and wear gloves and eye protection as a minimum. It almost goes without saying (yes, I am still going to say it) never mix acid with chlorine. They make several products that are designed to flush motors, boats, rods and reels etc. One is called salt away. I have never used it but plan to use it if and when I finish my boat and it ever gets to see the water. I have used a water softener in the past to rinse salt water.

Glen.

[Hookshurt]

On the use of the acid. Will it harm the exhaust hoses, fiberglass couplings,muffler, or cooling hoses that run from the water pump to the motor? Capt. Pat said it won't harm the impeller which is rubber, so I assume that it won't harm rubber components like the hoses, but I have to ask. Secondly, if I introduce the acid via a freeze plug for instance, how do I create enough pressure to push the acid up into the manifolds and ultimately the risers? The common theme I hear is that it does need to sit for a little while prior to flushing the acid out. Will the simple fact that there is an agent in contact with the corrosion be enough or does it need to be fully immersed? Am I making this more complicated than it should be?

[CaptPatrick]

On the use of the acid. Will it harm the exhaust hoses, fiberglass couplings,muffler, or cooling hoses that run from the water pump to the motor? Capt. Pat said it won't harm the impeller which is rubber, so I assume that it won't harm rubber components like the hoses, but I have to ask. Secondly, if I introduce the acid via a freeze plug for instance, how do I create enough pressure to push the acid up into the manifolds and ultimately the risers? The common theme I hear is that it does need to sit for a little while prior to flushing the acid out. Will the simple fact that there is an agent in contact with the corrosion be enough or does it need to be fully immersed? Am I making this more complicated than it should be?

Please, please, don't take this comment as a personal insult, I don't mean it as such.

From everything you've just ask, I really don't think you're qualified to tackle this chore and need to get a qualified marine mechanic to do it for you. But you need to be on hand and watch what he does and how he does it so that the next time you'll have the knowledge to do it yourself.

Br,

Patrick

[Hookshurt]

No offense taken whatsoever. THAT is one of the reasons I am here. I know there are limits to what I can and should do, but it does take the experienced to point it out to me sometimes because what may appear to be a simple task will quickly turn into a true fiasco. I've been there and done that more than once on this girl. Thanks for yours and the others' frank advise, regardless of what it is. I will contact a couple of the locals around here for some advise on who to use. Thanks!!!