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-   -   zincs for Yanmar 2GMF (http://www.sailnet.com/forums/gear-maintenance/38470-zincs-yanmar-2gmf.html)

Julie303 11-13-2007 04:07 PM

zincs for Yanmar 2GMF
 
Does the Yanmar 2GMF (fresh-water cooled) engine, including the heat exchanger, have anticorrosion zincs? If so, where are they?

SailorMitch 11-13-2007 04:12 PM

The 2GM20F has no zincs. :)

sailingdog 11-13-2007 04:36 PM

Are you sure SailorMitch? I'd imagine the raw-water side of the heat exchanger would have a zinc to protect it.

SailorMitch 11-13-2007 08:06 PM

Dawg -- The fresh water cooled engine does not have a zinc. The raw water version of the engine does. Common for fresh water cooled Yanmar's not to need a zinc anywhere.

lbdavis 11-14-2007 01:16 PM

I second the opinion (fact) that 2GMF's have no zincs.

AjariBonten 11-14-2007 01:58 PM

I'd take a good look at the heat exchanger though.

That should have a zinc.

Oops, doubled Dog's point.

SailorMitch 11-14-2007 02:16 PM

Quote:

Originally Posted by AjariBonten (Post 222650)
I'd take a good look at the heat exchanger though.

That should have a zinc.

Oops, doubled Dog's point.

The reason Yanmar techs have given me for no zincs is that Yanmar did not use dissimilar metals in the heat exchanger for the 2GM series. Trust me, my boat has a 2GM20F and I was going nuts trying to find the zinc when I first bought it. I then bought a Yanmar service manual clearly showing that the fresh water cooled engine does not have a zinc, but the raw water version does. I double checked my reading of the manual with the kind folks at both Torresen Marine and Mack Boring, as well as a couple of guys I trust online.

AjariBonten 11-14-2007 02:22 PM

Hmmmmmmmmm,

I may be way off, but it has been my experience that having dissimilar metals on the individual piece of equipment is only part of the problem.

I thought having dissimilar metals at alll in contact with seawater could be a problem.

Of course they may need to be electrically connected for it to be an issue; but in my experience, every piece of metal is electrically connected!

For instance, the heat exchanger might be bronze, the shaft stainless, the prop bronze, etc. etc. Even though the heat exchanger may not have direct connection to the engine, the potential (pun intended) is there.

I would retrofit a zinc in the heat exchanger if there is not a place for one.

Fred

SailorMitch 11-14-2007 03:03 PM

Fred -- Sorry, but I'm going with Yanmar on this one. If the engine needed a zinc, they would've installed one at the factory. If you ever own a 2GM20F, fell free to install a zinc. Mine is 20 years old and surely would've fallen apart from galvanic corrosion by now if it were an issue.

AjariBonten 11-14-2007 03:06 PM

No, I wouldn't argue with you. :)

How about the heat exchanger though? Isn't that separate from the engine?, or am I misunderstanding the layout. My experience is mostly with BIG Cats (4108's, etc.), or marineized automotive gas engines.

It seems to me that I replaced the heat exchanger zinc more often than any.


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