Yanmar - flushing the enigine? mixing elbows?

[Elizabeth Ann]

Dear Group,

There has been a lot of traffic here lately concerning mixing elbows and engine flushes. Like many of you, our Albin was bought used with little hours (under 500 when purchased). So it makes sense that the elbow is something that would be a concern to us.

I've been to two Yanmar certified mechanics in our area and, not surprsingly, I have heard two different opinions.

Mechanic A, says he can take a 'quick look' at the elbow to see if he thinks it's nearing the end of its lifetime. However, the guy keeps jerking me around as to when the'quick look' will actually happen. Yet, he won't let us make an appointment for service until he looks at it. Mechanic A says he's seen some elbows last 8 years.

Mecahinc B, says you need x-ray vision to tell if its 'going bad' and will gladly let us make an appointment for a replacement....though he's booking 3 weeks out.

The questions become,

(1) do I wait for the part to fail before replacement? Wht are the horror stories? Mechanic A claims a failed elbow can result in a blown engine, the manual says potential fire. Niether are good.

(2) do I wait for mechanic A to inspect and trust his judgement?

(3) do I allow mechanic B to do the job? A man who may just seem eager to take our money.

Finally, on a related note. Engine Flushing? Our sea strainer has a garden hose attachment fitting that t's off the strainer. Is this for flushing the engine with fresh water? Is there a proper procedure? I assume I shut the raw water intake?

Will flushing increase the life of the elbow? And other parts of the engine and cooling system? Will RydLyme help this situation, or does it only clean the exchangers?

I apologize for all the confusion folks, I'm trying to get all this straight and hoping to prevent some serious misfortunes.

Thanks in advance.


I've provided the following links as references:

http://albinowners.net/aog/viewtopic.ph ... t=flushing
http://albinowners.net/aog/viewtopic.ph ... t=flushing
http://albinowners.net/aog/viewtopic.ph ... t=flushing
viewtopic.php?t=1033
viewtopic.php?t=892&highlight=rydlyme

[chiefrcd]

Been there done that...don't wait for it to fail, depending on your situation youare are dead in the water and pumping sea water and 900 degree exhaust into your engine compartment. Mine failed after I had a Yanmar Certified Service Center check it out....it looked good, it didn't last. My recommendation is to change it out per the service manual. It is very cheap pot metal and when it snaps, it snaps as clean as if you had sawed it off. In fact when my let go, I though it had slipped out of the mixing portion but in actuality it had broken off clean at the flange. I have no idea how long the actual mixer will last. It's the elbow that goes bad, but since it all seems to be made from the same material, I changed out the elbow, the mixer and all the clamps to the tune of about $1270.00 if memory serves me. (Thats parts only). As far as flushing, I'm sure it will help the over all condition of your sea water cooling system. It will have no effect on the elbow in question as sea water does not flow into that area. The sea water mixes with the exhaust coming out of the turbo, through the elbow and into the mixer. The sea water is down stream from the elbow.

[Elizabeth Ann]

Thanks for the quick response Chief!

[RicM]

I have a very smart,young, Yanmar certified mechanic with a degree in mechanical engineering:

My question:

> Thanks very much. At least we know they were changing the zincs, but
> just as I feared, things like the zincs in the heat exchangers that
> "don't show" are where the danger usually lies. What do you think about
> flushing systems for the heat exchanger? I have heard about both fresh
> water and Salt-a-Way flush systems to flush the raw water side, usually
> installed on the sea strainer, and would be curious to find out what you
> think about them. Have you ever installed one?

His answer:
The flushing systems are for salt formations and do not attack the zinc accumulation. They may be a good idea on a raw water cooled steel engine block, but all of your engines salt water exposed parts are cupru-nickle or aluminum. Its up to you, but I believe that a thorough flush/cleaning when needed will produce better results because the daily flushing additive just isn't strong enough to remove the hard deposits.
JP

[Elizabeth Ann]

Its up to you, but I believe that a thorough flush/cleaning when needed will produce better results because the daily flushing additive just isn't strong enough to remove the hard deposits.

Thanks Ric. When he said 'daily flushing additive', is he refering to the Ryd-Lyme (salt away or salt-ex)?

[chiefrcd]

I think Ryd-Lyme is more of a annual flush. I'm not sure I'd want to flush that through my system too often. I did it last year and got a ton of brown gunk out of my saltwater side cooling system. It's a pretty strong acid solution.

[RicM]

My take-away was that the additional cost, effort, and probably the ecological impact of flushing acid into the Bay after every trip is not really that helpful in a fresh-water cooled system. The whole salt water side is somewhat sacrificial in an effort to protect the more expensive machinery on the enclosed coolant side. Not so on a raw water cooled machine.

[Merry Kate]

Routine engine flushing (after each use) is just running fresh water through the raw water side. There are modified sea strainer lids available for most strainers like Perko and Graco that have a garden hose fitting with a ball valve to run water through at the dock, or you could make one if you have a little fabrication skill. Flushing after every run in salt water doesn't as much remove deposits as lets the system sit idle for days & days with fresh water in the system vs. seawater, which is where most of the deposits and corrosion will be produced. Doing this every time you come in is probably a PITA, but will add years of life to the cooling system.

An acid flush is a (very) periodic maintenance procedure to remove any & everything built up in the raw water side. Old fashioned way is muriatic acid, which is very dangerous to humans, the environment, and metallurgy. Ridlyme is some kind of organic acid (citric or something) that works absolute wonders and is (supposedly) environmentally friendly. They make a marine formulation that is (also supposedly) kinder to marine cooling system metals, like cupro-nickel heat exchangers. I did this after something like 5 or 6 years of mainly freshwater use, and it took 5 deg off my running temperature.

Here is a thread from last year relating to this topic and the set-up I used:

http://albinowners.net/aog/viewtopic.ph ... highlight=

[Elizabeth Ann]

Thank All!

Can someone confirm - should the engine be running while the raw water side is flushed? Also, if running should it be at idle or a fast idle?

Cheers.

[chiefrcd]

I'd say run it...only because some exhaust systems will allow water to build to a point that it will back up into the turbo/exhaust/valves/piston's of your engine...and of course that is NOT a good thing.

[Merry Kate]

Elizabeth Ann -

Definitely with the engine running. A fresh water source connected at the sea strainer would'nt make it past the raw water pump impeller anyway without the engine running.

Check on boatdiesel for much info about the flushing procedure.

[Elizabeth Ann]

Thanks all - you've been a great help!

[DrNickS]

Has anyone done this on a Yanmar? I spoke with a Yanmar tech and he said not to run the engine. Also he said the engine does not have to be warm. He said to remove the hose on the engine side of the raw water pump and remove the hose on the mixing elbow and run the solution through using a small bilge pump. He said not to run in through the sea strainer. This would have been easier for me since I have a garden hose fitting for fresh water flushing after each use.

If anyone has photos of your setup on a Yanmar I would appreciate seeing them.

Also does it matter which direction I pump it? It seems that it would be easier to start from the mixing elbow and let gravity take it to the engine side of the raw water pump, catch it in a bucket and then let the small bilge pump circulate it back up to the mixing elbow. Any thoughts?

[Elizabeth Ann]

DrNickS,

Are you talking about the RydLyme? Chief has a Yanmar and he's done it, I'm sure he'll chyme back.

For now I was asking about the fresh water flush....I have the hose adapter too. How have you done the fresh water?

I plan to use the RydLyme in the fall (or next spring) since the boat is in the drink all ready.

[Merry Kate]

Elizabeth Ann -

Definitely with the engine running. A fresh water source connected at the sea strainer would'nt make it past the raw water pump impeller anyway without the engine running.

Check on boatdiesel for much info about the flushing procedure.

PS: Wanted to be clear: the routine fresh water flush is done with the engine running. The rydlime flush is a more elaborate procedure that requires an external circulating pump with the engine stopped & cool. For the rydlime flush I rigged, I went in at the inlet to the marine gear cooler and out at the outlet of the engine heat exchanger, just before the exhaust elbow.