"flushing" a sea water cooled engine ?

[rogerroger]

Whenever I can I run my tender's outboard in a dustbin of fresh water to remove the salt that builds up.

Should I do this with my inboard direct cooled Yanmar YSM ? - taking the inlet pipe off the seacock and sticking it in a large bottle of fresh water?


Roger Holden
www.first-magnitude.co.uk

 

[ccscott49]

Re: \"flushing\" a sea water cooled engine ?

It definitely would not do the engine any harm, thats for sure, but I would use a hose pipe on the inlet, but start engine then turn on hose imediately, then trun hose off and stop engine imediately, what I mean is do not run hose without engine running, as it may build up back pressure and force water into engine or, put hose in big bottle, bucket and allow engine to draw from that, have I made sense?

 

[Paulka]

Re: \"flushing\" a sea water cooled engine ?

I do this on a regular basis, usually when changing oil, or on rainy "maintenance day".
I just use a bucket rather than a bottle, ..... and keep the bottle of corrosion inhibitor for me!

;-)

Paul

 

[rogerroger]

Re: \"flushing\" a sea water cooled engine ?

thanks - can you recommend a corrosion inhibitor ?



Roger Holden
www.first-magnitude.co.uk

 

[rogerroger]

Re: \"flushing\" a sea water cooled engine ?

Thanks Colin

Do you think I should have done this when I took her out of the water last winter ?

Could salting up explain why I had a blocked thermometer at the weekend?

Roger Holden
www.first-magnitude.co.uk

 

[ccscott49]

Re: \"flushing\" a sea water cooled engine ?

Could well have caused it, but it should be ok now, I would do it before lay-up. I've found that soluble oil, used as cutting fluid, on lathes milling machines etc, mixed with antifreeze and water flushed through, inhibits rusting and the antifreeze protects from freezing, in any water left in there. a good flush never did anybody/thing any harm!

 

[vyv_cox]

Re: \"flushing\" a sea water cooled engine ?

If I can jump in on this, fresh water flushing and corrosion inhibition on a cast iron engine is a good idea but not the end of the world if you don't. Cast iron is a wonderful material that takes almost everything thrown at it. (except impacts!) What flushing does do is help to remove salt deposits from small passageways and clearances, but if these are in hot parts they will be calcined up anyway so it may not make a lot of difference.

The most convenient inhibitor is antifreeze. Most people use the "once-through" principle but I doubt that this really does much. Here's a really good idea, not mine, for circulating it. Get a plastic five-gallon bottle and cut a big hole in it, near the top, that will take the coolant flow from your exhaust. Hang this bottle over the transom or wherever to catch the water coming out of the exhaust. Mix up a couple of gallons of water and antifreeze at about 25% concentration. Take a hose from this bottle to the suction of your water pump. It's usually best to pre-fill this hose to make sure that the pump primes but it doesn't need to be completely air free. Run the engine for 10 minutes or so. Exhaust gases escape through the hole in the bottle and coolant is recirculated. Keep an eye on coolant temperature as it should not boil but getting it up to 80 degrees or so will help to remove unwanted deposits. If you really feel that there is a blockage, add some radiator flush or similar product as well. For really bad cases a pint or so of hydrochloric acid will not normally do much harm and is very effective at removing rust, but don't try it if there is much non-ferrous metal in the engine. For most small marine engines it is quite safe. If you used acid flush with fresh water afterwards, otherwise leave for the winter or carry on as normal.

 

[Paulka]

Hmmm!
For the engine, car antifreeze.

For you .... and me : Rioja!

;-)

 

[rogerroger]

Re: \"flushing\" a sea water cooled engine ?

I do find that over Rioja-ing tends to result in engine misfires some 8 to 10 hours later...

Roger Holden
www.first-magnitude.co.uk

 

[WayneS]

Re: \"flushing\" a sea water cooled engine ?

Flushing with a lot of water before switching off for the night does help but does create a problem where you have to get things fired up quite regularly to pump the bilges.

Golden rule though, Rioja-ing after Liebfraumilche-ing is OK but never, never do it the other way around. Causes total system collapse.

 

[oldsaltoz]

Re: \"flushing\" a sea water cooled engine ?

G'day Roger.
A Very Old Salt told this old salt, that half a cup of brake fluid on top of the cooling water just prior to a vary slow draining of the block (just a fast drip rate). Would provide a coating on the internal cast iron thus preventing rust during the lay up and for some time after as brake fluid migrates into steel. Come to think of it, I have never seen a brake fluid container on a car go rusty and the new paint peels off 6 months after you buy a new car. Has anyone else heard this, or is it just old salt?
Though I’m not sure how you would get water into a salt water cooling system, perhaps remove an anode bolt. No, can that idea, you would have to remove the old oil from a salt water cooled engine or cause more polution than we have now.

Avagoodweekend Old Salt Oz……

 

[Twister_Ken]

Brake fluid probably not

Having seen what brake fluid does to paintwork (one learns from one's mistakes!) I'm not sure how good an idea this would be. One of the proprietary rust inbitors might be a be a safer bet.

 

[kgi]

Re: \"flushing\" a sea water cooled engine ?

be careful using acids if your raw water strainer is plastic as it cracks them up .....been there done that....

 

[ccscott49]

Re: \"flushing\" a sea water cooled engine ?

Brake fluid is agroscopic, it absorbs water, (not the slicon type) and actually causes brake pipes to corrode, from the inside out, so I wouldn't use it as a corrosion inhibitor!

 

[Guest]

Re: \"flushing\" a sea water cooled engine ?

I took on this job a couple of weeks ago for my raw water cooled, atomic four gasoline inboard engine. I mixed 1/3 u.s.gallon of muriatic acid (muriatic acid is a 30% solution of hydrocloric acid sold in hardware stores) with 5 u.s. gallons of freshwater. I used a cheap Jabsco pump which fits on the end of an electric drill to power the acid soultion through the engine block with the discharge of acid and goop being directed onto a large bucket. As I got towards the bottom of the 5 gallons of the clean acid solution, I let the acid just sit in the engine for 15 minutes.

I then rigged a garden hose to the marina fresh water supply and flushed the engine with the fresh water flowing in the usual direction through the block as well as then back flushing the engine with the water under pressure flowing in the reverse direction.

Lots of scale, black stuff and other crud came out in both directions.

Thereafter I ran the engine and was pleased to note that the basic operating temperature was 25 degrees f lower than before the flush. (I use a manual thermostat which allows me precisely to control the operating temperature.)

If you have access to pressure water, the job really is pretty quick and easy.

krgds

pearlfish

 

[longjohnsilver]

Dromus B?

Read about this stuff made by Shell a few years back, article said it was made to break down salt deposits, only problem being that I have never found any or anybody else that's even heard of it.

Has anyone out there used it? If so did it work and where did you buy it?

 

[vyv_cox]

Re: Dromus B?

Dromus B is a soluble cutting oil used for machining processes. I cannot see that it has the slightest use in flushing an engine, but what do I know?

 

[ccscott49]

Re: Dromus B?

Thats the stuff, I reccomended for preservation, earlier in the thread, I can't see it being any use either for actual flushing of salts/calcification away, but preservation, yes. But are you sure it's dromus, that name doesn't ring a bell. Used to use gallons of the stuff, when I was an apprentice fitter/machinist.

 

[vyv_cox]

Re: Dromus B?

I have the book in front of me as I write.

 

[ccscott49]

Re: Dromus B?

Well done! Now I know, I will make a note of it, its useful stuff.