Yarmar 6LY-STE engine

[Iggy]

I have a question on zincs. I bought my boat last year so all this is new to me.

The past owner left me with two sizes of zincs. The smaller one comes from the heat exchanger that uses three of them. The bigger ones, I can not find them on the engine or in the service manual. Would anyone know?


The other pic, is comes from the starboard side of the engine. Is that a plug or a zinc? I am thinking that its a plug.



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[DavidM]

You have a question? I know that engine pretty well.

David

 

[Iggy]

You have a question? I know that engine pretty well.

David

Yes I do. Sorry about that, I posted the message before I finishing it. I was not sure that the pics would upload.

 

[Lollygag1]

That larger one is a zinc on the starboard side. Very easy to access. If I recall there are 3 of the smaller ones on port and two on the starboard.

 

[DavidM]

There are typically five zincs: Two on the forward end of the main heat exchanger, 1 on the aft. One on the after cooler which is the one your arrow is pointing to and one on the lube oil cooler underneath and forward. There is sometimes a sixth one on the transmission cooler.

I generally got 1/2 year out of the after cooler zinc which wastes the fastest, about a year out of the lube oil cooler zinc and 1-2 years out of the main heat exchanger zincs. This was in fairly salty bay water.

You can buy the brass plugs with zincs or just zincs for much less money. When you screw in a new zinc into the plug use pliers to get it tight because if you don't they sometimes fall out of the threads and get left in the cooler.

If you wait too long (and you should replace when half gone) and one corrodes to pieces but leaves a stub in the brass plug there are a couple of ways to get it out. One is to drill a hole in the zinc and use an easy out. The other way is to put it in a jar of Barnacle Buster, Rydlime, etc and let the acid eat it up.

Good luck.

David

 

[Iggy]

There are typically five zincs: Two on the forward end of the main heat exchanger, 1 on the aft. One on the after cooler which is the one your arrow is pointing to and one on the lube oil cooler underneath and forward. There is sometimes a sixth one on the transmission cooler.

I generally got 1/2 year out of the after cooler zinc which wastes the fastest, about a year out of the lube oil cooler zinc and 1-2 years out of the main heat exchanger zincs. This was in fairly salty bay water.

You can buy the brass plugs with zincs or just zincs for much less money. When you screw in a new zinc into the plug use pliers to get it tight because if you don't they sometimes fall out of the threads and get left in the cooler.

If you wait too long (and you should replace when half gone) and one corrodes to pieces but leaves a stub in the brass plug there are a couple of ways to get it out. One is to drill a hole in the zinc and use an easy out. The other way is to put it in a jar of Barnacle Buster, Rydlime, etc and let the acid eat it up.

Good luck.

David

First off, Thank you!!

I don't have an arrow in the pic. In the first pic dead center, thats a zinc?

Ok, I will need to really look for that 5th zinc!!

 

[Bacchus]

Here are the pages from the manual relative to zincs.

 

[DavidM]

Yes, middle of first pic. I looked closer and what I thought was an arrow was a bright yellow wire or something.

David

 

[Iggy]

Yes, middle of first pic. I looked closer and what I thought was an arrow was a bright yellow wire or something.

David

Thanks! What you saw was the dip stick to the transmission.

That zinc, I though it was a plug and all I could think of since the oil filter was above it. That by removing it I would would oil running down the side of the engine.

 

[Iggy]

For the next boater having the same problem. In replacing the 2 zincs that I don't know about. I found two more for the Twin Disc transmission cooler.

 

[Bacchus]

For the next boater having the same problem. In replacing the 2 zincs that I don't know about. I found two more for the Twin Disc transmission cooler.

I believe the tranny coolers are selected & added by the builder and won't show or be accurate in any engine or tranny manuals. Builders documentation varies all over the lot and may or may not be there.

 

[Iggy]

I believe the tranny coolers are selected & added by the builder and won't show or be accurate in any engine or tranny manuals. Builders documentation varies all over the lot and may or may not be there.

Forgive me, thats way I mentioned Twin Disc. You're right, you must treat it as two different units.

I will say, I went to two different trusted people that told me only the heat exchanger had zincs. After finding different size zincs I know something was wrong. IT WAS THIS FOURM THAT SET ME STRIGHT!

Thank you everyone.

 

[rgano]

On my Yanmar 6LPA-STP I have adopted the practice of pulling all five ANODES (since I use Secure Core AL instead on ZN) every 90 days because regardless of whether AL or ZN, they swell as they corrode and can stick in there and break off right at the threads of the brass holder leaving you a big chunk of anode in your cooler and a stub in your holder. I wrap the removed anodes in a paper towel and tap them with a hammer to remove the corroded parts. If they are over fifty percent intact, I will reinser them. Muriatic acid in a small jar will eat old broken off stubs out of a brass holder in a very short order, been doing it for thirty or more years when necessary.