Phosphoric Acid

[Hugz]

I'm thinking of phosphoric acid as 1 to 1 solution with water and doing a flush of the cooling system after use whenever I'm not going to use the motors for a while.... any thoughts? Panelbeaters use it as a rust retardent.

http://www.metalwebnews.com/howto/rust/rust.html

[Vic]

Its an idea but i dont think I go to that much trouble. How are you going to do it? Presumably not by running it in bucket of the stuff I just flush mine through with a hose

[niander]

Please stop playing with the colours...my eyes dont like it!

[Vic]

Some colours would be quite gay

[pistnbroke]

I dont think this is worthwhile as the acid does not penetrate scale rust very well at all.. Flooding the inside of the block with diesel would be a good idea particulary if you could incline the engine to let it soak

[Horsley-Anarak]

If I cant read it easily I just dont bother.

I agree please stop playing with the colours

It you flush the engine with phosphoric acid, the surface layer of rust will be converted to iron phosphate.
A thick wet rust layer underneath the iron phosphate layer will still continue too corrode if there is moisture present.

I think that the method that I would use would be to flush out any salt in the engine, then blow it out with an air line followed by a good squirt of WD40.

Then store the engine in a dry enviroment, hanging them on the radiators works well

H-A

[Hugz]

You would think there would be some product that can seal the surface inside the water jacket that would be a barrier between water and iron. Interesting an owners manual for the aussie built outboard (riptide) recommends running the motor dry for a few minutes to burn off the moisture.

[chris]

colours are hard to read, yellow is impossible
I flush mine in water with dishwashing liquid in the water, makes lots of froth but it seems to work, if I used clothes detergent I could probably do my washing at the same time. I always store mine standing up in a shed. They can go a very long time without being used with no worries if they are flushed properly

[Collector Inspector]

Phosphoric Acid

NO!

Others are better, see my previous.

C.I.

[rosbullterier]

It appears the recognised cleaning elixir for marine engines cooled by raw water is termed Muriatic acid.

Having recently spent many internet hours in many related marine forums to search various aspects in restoring two large elderly OMC engines, it seems the recognised US swimming pool cleaner is what is universally used for their annual boat flushing /soaking service.

It is hydrochloric acid. So it won't convert your rusty clag into iron phosphate like phosphoric acid.

I havn't used it. I spent two days per engine with varied shaped chisels chipping out the clag through the water galleries around the cylinders. They were solid.

I will be interested in a review of this less physical method of creating water flow.

[Horsley-Anarak]

Hydrochloric acid, HCl or spirits of salts will readily dissolve lime scale.

Have used it to clean out my steam cleaner, but am not sure if it will help with rusty engines.

I find the best way to buy it is as spirits of salts from the local ironmongers, It is quite concentrated ( it smokes) so use with caution.

Does a fantastic job of descaling the bog

H-A

[rosbullterier]

So does caustic soda - what's that?

[Horsley-Anarak]

Sodium Hydroxide (NaOH)

H-A

[rosbullterier]

Does that make it alkaline rather than an acid?

[timberman2004]

interesting one this

I'm a bit leery of the chemicals and logically you'd want one that specifically attacks iron oxide, FeO2, rather than just iron ?
but all this stuff would have to sit and fizz for quite a while for the proper result

either way I think much of the problem is loose bits floating about and blocking the exit ...specially on old 102s

Had a satisfactory result in removing ALL brass work from the 102 block so apertures as big as possible
a good old poke about with flexible wire as much as poss and then air line or pressure jet to blow / flush out the gubbins ...
amazing what can come out

similarly a back and a frontways blasting for the square block models

my intrepid 'Seagull Test and Evaluation Tank is particularly oily as I seldom change the water
probably not scientific, but believe that this oily flushing through a warm / hot engine helps to coat the insides and prevent recurrence
I guess that's right up there with eye of bat, and skin of newt remedies, and wafting a sprig of St Johns Wort over the powerhead

I ALWAYS flush thoroughly after contact with seawater