Cooling Water Valve on a SD20

[Sailorman Ed]

the cooling water SO valve on my SD20 will not shut off. In preparation of being hauled, what is the likely issue and can it be repaired as opposed to being replaced? And how often do these zincs need to be replaced?
thanks,
Ed

[Wanderlust]

I have one the same.

Last haulout the mechanic removed it and worked on it for a while because it was very stiff. Now it turns OK but I can't turn it it off hard enough for it to fully close, and it still dribbles water. So I plan to replace it shortly.

There was a thread about this a couple of years ago and it seems a common solution to replace it with a ball valve.

http://www.cruisersforum.com/forums/...es-106818.html

I plan to do the same, but using bronze instead of stainless. The original seacock is bronze.

[Dulcesuenos]

We have hauled relaunched many times and never an issue not closing the valve. Not being able to close it is handy if you need to service the strainer or raw water pump at sea or in the water.
AS for Zincs on the yanmar SD20 there are No zincs on the engine or the drive except for the zinc at teh front of the prop. The manuakls are all wrong, not sure why they drew them their.

[mfeene01]

I have a pair of SD20s and both valves are stuck open. If I need to service a raw water strainer in the water I disconnect the hose at the strainer end and plug it. If you have a plug ready to go, not much water gets into the boat.


Both of my SD20s have a pencil zinc on the side opposite the water valve. I check them when I check my prop zincs and replace as needed.


MikeF

[Wanderlust]

Originally Posted by Dulcesuenos

....... there are No zincs on the engine or the drive except for the zinc at the front of the prop.

As MikeF noted they do have zincs. Here is a photo. They seem to last pretty well as I haven't replaced mine in 3 years.

[Sailorman Ed]

Wanderlust - thanks for the great link to the earlier discussion and the post by Kiltym - I had never heard of the DZR CR material - I learned something. Now to see if I can find a source in the US for that. I like the idea of a ball valve as reaching over the hot exhaust is not my idea of fun in a cramped space. This was very helpful.
Ed

[Dulcesuenos]

Holy cow i must admit I was wrong and mislead by the yanmar dealer. My buddy I got the boat from was also was mislead, I guess this isnt bad for 9plus years old mine has about 75 percent left



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[wiekeith]

I replaced mine with a stainless steel ball valve on my SD50 - pic attached. Need to make sure you use some anti-corrosion barrier on the thread into the saildrive casing though as aluminum and stainless are not good partners!

[ggray]

Every haulout (used to be every other year, but I couldn't get hauled last year, having trouble this year, so am pushing 3 1/2 years now) I remove and lubricate the kingston cocks on my SD20s. Still the originals, and 15 years old now.

They can be right tight at the end. I usually only operate them when winterizing and in the spring. I say this just to indicate that my lube jobs must be effective.

One thing I have done to help operate the valve w/o wringing something off should the valve be extra tight is to modify a socket (I think a 9/16 12 point is the best fit) by cutting slots on opposite sides that slide over the handle rod. With that and a nice extension you can then put a good symmetrical torque on the valve.

[GrahamHO]

Originally Posted by Dulcesuenos

We have hauled relaunched many times and never an issue not closing the valve. Not being able to close it is handy if you need to service the strainer or raw water pump at sea or in the water.
AS for Zincs on the yanmar SD20 there are No zincs on the engine or the drive except for the zinc at teh front of the prop. The manuakls are all wrong, not sure why they drew them their.

Maybe you haven't found the anodes yet? How long have you had the engine?
If yours is a heat exchanger engine I can't advise but:-

My Yanmar raw water cooled 1998 2GM 20 SD has a zinc in the block on the exhaust side, another zinc at the rear of the cylinder head, and another zinc on the right hand side looking aft in the water passage from the sail drive intake. They are all accessed by unscrewing large about 1" hex plugs. The zincs are rods about 1,1/2" long by about 1/2" dia. screwed into the inside of the hex plugs. The hex plug in the block side is a taper thread and the other 2 have copper washers. The one at the rear of the head is easy to overlook but it's there.

I put a smear of grease on the threads of the anode hex plugs to prevent them corroding in place. It also prevents salt deposits bleeding to the outside. A fairly long 1/2" drive bar and socket are best to remove the anode housings.

Also of course the prop anode which has been redesigned in the last year or so as two pieces, made of aluminum alloy. It's no longer necessary to remove the prop to change it.

I have the bronze type of shutoff valve for the raw intake that takes around 18 part turns to open fully. I always close it when the boat is not in use. I also regularly spray some lanoline around the engine and on that valve. This gets inside the barrel and keeps it free. Keeping using it also keeps it free.

A neighbouring vessel has the same motor and the owner says he never closes the water intake and he can't now as it's stuck in open. Imagine it's just salt deposits and some gentle work could free it. A bit of WD40 and some working with a 10" crescent on the T should do that.

There is a replacement shutoff lever type valve available but I've found no need to change it.

Caution. There is an oil line from the right hand side (looking aft) of the block running around and under the zinc anode plug behind the cylinder head. The oil line supplies the valve rocker gear in the head. When changing that anode, some sea water inevitably dribbles over that painted steel oil line. I also spray that oil line with lanoline and check by hand for corrosion. I have replaced it once as a precaution as it had some pitting.

If your Yanmar is raw cooled and has no zinc anodes maybe it's a Chinese copy....Are your manuals written in Chinese? Sorry just kidding.

[Dulcesuenos]

I posted that I found the large zinc on the side of the upper gear housing. It was in good shape for o plus years old but replaced it anyways. My engine is fresh water cooled. There are zero zincs on the engine kr heat exchanger That may have been the confusion yanmar telling me no zincs

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[GrahamHO]

Originally Posted by Dulcesuenos

I posted that I found the large zinc on the side of the upper gear housing. It was in good shape for o plus years old but replaced it anyways. My engine is fresh water cooled. There are zero zincs on the engine kr heat exchanger That may have been the confusion yanmar telling me no zincs

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Fresh water cooling will be the reason for no zincs. You don't have any zincs in your car cooling system do you. And I'm sure you use an antifreeze type of corrosion inhibiter coolant rather than plain fresh water.
Likewise my zinc on the upper gear housing doesn't wear much. I clean it with a brass brush and replace it occasionally observing the caution to be out of the water.

My main regret with my Yanmar is not buying the fresh water cooled version. I completely overhauled mine after 15 years and considered replacing but that was 2 X the cost. It runs beautifully anyway.
Fresh water cooled engines last longer due to being able to run at a higher more beneficial temperature.

[makana]

I had to replace one if the valves on my SD20 saildrives last fall due to not closing completely. They coast around $60 and the part number is 196420-02290. In opened and closed them each a few times each season but after 8 years the starboard would not completely close.

The zincs on the saildrive block I replace every other year when hauled, part # 128370-13201. Last year I replaced the mixing elbows, there was corrosion on their inside, their outside was spotless (3000 hr on engines, 3YM30) part # 128397-13530

Cheers

[Dulcesuenos]

Originally Posted by GrahamHO

Fresh water cooling will be the reason for no zincs. You don't have any zincs in your car cooling system do you. And I'm sure you use an antifreeze type of corrosion inhibiter coolant rather than plain fresh water. .

Actually I have owned 6 Westerbekes and a few volvos that were all FWC and all of them had pencil zincs on the saltwater side of the heat exchanger. Not so with the yanmar 2gm2O w FWC system. I guess if your experience
Was limited to Raw water cooled only you wouldn't have known would you...

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[GrahamHO]

Originally Posted by Dulcesuenos

Actually I have owned 6 Westerbekes and a few volvos that were all FWC and all of them had pencil zincs on the saltwater side of the heat exchanger. Not so with the yanmar 2gm2O w FWC system. I guess if your experience
Was limited to Raw water cooled only you wouldn't have known would you...

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The discussion was specially about zincs in Yanmar 2gm 20s. They are shown in the manual in the block and head and someone said his didn't have any. We were specifically discussing those zincs in the block and the head. There is either sea water or freshwater coolant there depending on the model. The seawater cooled does have zincs. The fresh cooled doesn't need zincs THERE any more than your car does.

Obviously there will be zincs in the saltwater part of any heat exchanger.