Pencil Zinc location for Yanmar 2GM - SailNet Community
 2Likes
Reply
 
LinkBack Thread Tools
post #1 of 11 Old 04-04-2014 Thread Starter
Junior Member
 
Join Date: Jun 2011
Posts: 4
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Pencil Zinc location for Yanmar 2GM

I am moving my boat to salt water this Spring and want to inspect/ install new pencil zincs in the Yanmar (if there are any). Where are they located on the engine? and how often should I inspect them once in the Gulf of Mexico?
drharvell is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 11 Old 04-04-2014
Senior Member
 
JimsCAL's Avatar
 
Join Date: May 2007
Location: Glen Cove, NY
Posts: 3,400
Thanks: 2
Thanked 116 Times in 108 Posts
Rep Power: 10
 
Re: Pencil Zinc location for Yanmar 2GM

My 3GM30F has no zincs due to the heat exchanger material (Cu-Ni). I suspect your engine is the same.
JimsCAL is offline  
Quote Quick Reply Share with Facebook
The Following User Says Thank You to JimsCAL For This Useful Post:
drharvell (04-13-2014)
post #3 of 11 Old 04-05-2014
Senior Member
 
Join Date: Jun 2004
Location: western LI sound, L.I., N.Y.
Posts: 514
Thanks: 1
Thanked 15 Times in 15 Posts
Rep Power: 13
 
Re: Pencil Zinc location for Yanmar 2GM

a 2GM raw water cooled motor, will have zincs in engine.
My 3GM raw water cooled motor has 2 zincs on starboard (fuel
filter/dip stick) side and 1 in back.
The 2GM raw water should have 2 zincs, 1 in the block on the dip stick side, just behind/above it . A second is on the rear side of the head. Check manual, should be available free on line.
...(1 could be hiding behind fuel filter like my 3GM)
uaglt likes this.
HUGOSALT is offline  
Quote Quick Reply Share with Facebook
The Following User Says Thank You to HUGOSALT For This Useful Post:
OPossumTX (04-05-2014)
post #4 of 11 Old 04-05-2014
Don't call me a "senior"!
 
Puddin'_Tain's Avatar
 
Join Date: Feb 2014
Posts: 968
Thanks: 0
Thanked 32 Times in 29 Posts
Rep Power: 3
 
Re: Pencil Zinc location for Yanmar 2GM

http://j30.us/files/Yanmar-2GM20-Parts-List.pdf

Figure 1, part 18 is the zinc. Part 16 is the plug that holds it; it has a fairly large hex head on it and screws directly into the stb side of the block (in a standard installation).

Figure 11, part 24 is the zinc. Part 22 is the plug; it screws into a cast iron plate (part 19) that attaches to the back of the head.

Don't be surprised if you need penetrating oil, a cheater bar, and some choice language to get the plugs out. You can get the zincs at West Marine, or on-line from a number of sources.
uaglt likes this.

"If a man must be obsessed by something, I suppose a boat is as good as anything, perhaps a bit better than most." --- E.B. White
Puddin'_Tain is offline  
Quote Quick Reply Share with Facebook
post #5 of 11 Old 04-13-2014 Thread Starter
Junior Member
 
Join Date: Jun 2011
Posts: 4
Thanks: 1
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Re: Pencil Zinc location for Yanmar 2GM

Quote:
Originally Posted by JimsCAL View Post
My 3GM30F has no zincs due to the heat exchanger material (Cu-Ni). I suspect your engine is the same.
After lots of reading in this any other places, I agree that the Yanmar 2GM20F (fresh water cooled- has antifreeze canister) indeed has NO zincs in it - due to the unique corrosion resistant alloy used in the heat exchanger (the only part of the engine to contact sea water). The 2GM20 (entirely sea(raw) water cooled) does have the pencil zincs since the sea water contacts various parts of the engine block during its cooling cycle.

I ran across this info during my research. . . There is a lot of controversy surrounding the proper use of zincs and electro galvanic corrosion in general and I encourage everyone to be aware that there is a huge difference in the high quality marine Bronze (which is copper+Tin alloy) through hulls and fittings and some BRASS (which is copper + Zinc alloy) thru hulls and fittings/ adapters being sold. Attaching a brass fitting to even an excellent bronze thru hull or valve creates a high potential for corrosion and catastrophic failure even if you electrically bond everything together. The Zinc in the alloy acts just like a zinc should !! Just sayin' -- know what is on or being put on your boat!
drharvell is offline  
Quote Quick Reply Share with Facebook
post #6 of 11 Old 04-15-2014
Junior Member
 
Join Date: Apr 2014
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Re: Pencil Zinc location for Yanmar 2GM

yes - one of the anodes is hidden behind the fuel filter - a really dumb location because you will probably have to take the fuel system apart to get proper access with a ratchet wrench with a 25mm (or very close imperial equivalent) socket - dont try anything else - it takes a lot of torque to get these puppies out and I see several posts where people have "rounded" the anode holder hex head (presumably using a monkey or pipe wrench) and now cant get them out.........

Last edited by uaglt; 04-15-2014 at 08:29 PM.
uaglt is offline  
Quote Quick Reply Share with Facebook
post #7 of 11 Old 08-21-2015
Junior Member
 
Join Date: Aug 2015
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Re: Pencil Zinc location for Yanmar 2GM

Quote:
Originally Posted by drharvell View Post
After lots of reading in this any other places, I agree that the Yanmar 2GM20F (fresh water cooled- has antifreeze canister) indeed has NO zincs in it - due to the unique corrosion resistant alloy used in the heat exchanger (the only part of the engine to contact sea water). The 2GM20 (entirely sea(raw) water cooled) does have the pencil zincs since the sea water contacts various parts of the engine block during its cooling cycle.

I ran across this info during my research. . . There is a lot of controversy surrounding the proper use of zincs and electro galvanic corrosion in general and I encourage everyone to be aware that there is a huge difference in the high quality marine Bronze (which is copper+Tin alloy) through hulls and fittings and some BRASS (which is copper + Zinc alloy) thru hulls and fittings/ adapters being sold. Attaching a brass fitting to even an excellent bronze thru hull or valve creates a high potential for corrosion and catastrophic failure even if you electrically bond everything together. The Zinc in the alloy acts just like a zinc should !! Just sayin' -- know what is on or being put on your boat!
I have been going nuts trying to locate the Zincs on my 2GM20F, your post is the first I have found that says there are none. But since the manual simply says they would be behind a cover labeled with a sticker that says "Anticorrosion Zincs" and no such sticker is on my 1988 engine, I'd say you are correct.
GansettSailor is offline  
Quote Quick Reply Share with Facebook
post #8 of 11 Old 08-21-2015
Senior Member
 
Join Date: Apr 2012
Location: Tasmania
Posts: 122
Thanks: 0
Thanked 12 Times in 12 Posts
Rep Power: 5
 
Re: Pencil Zinc location for Yanmar 2GM

Post #3 above is correct for locating the zincs in a raw water cooled 2GM.

As mentioned, they can be a mongrel to remove. The one on the side near the dipstick is a bit tricky because the socket wrench that you will need may foul the high pressure fuel line. By grinding metal away from the cheek of the socket you should be able to wriggle it in and use a short extension to a very long bar that you will probably need to get enough leverage.

I have found that running in salt water but giving the cooling system an occasional flush out with fresh water, I get a good 18 months before the zincs are down to about 50% . But what you get will depend much on your own installation, as no two boats are the same in the way they are wired up and how well metal components are isolated. I would certainly recommend that you check zincs after the first year in salt water until you know for sure. Don 't be alarmed if they are almost gone - that shows that they are doing their job.

If your engine has a closed cooling system (fresh water cooling), while the engine itself won't have zincs, it is possible that the heat exchanger will have at least one in the salt water jacket (and maybe not very obvious). Same advice - check it after a year. Also consider setting up a method to flush the heat exchanger itself.
arvicola-amphibius is offline  
Quote Quick Reply Share with Facebook
post #9 of 11 Old 08-22-2015
Senior Member
 
Join Date: Apr 2008
Posts: 635
Thanks: 25
Thanked 27 Times in 27 Posts
Rep Power: 9
 
Re: Pencil Zinc location for Yanmar 2GM

I had a 2GM20 with a Sendure heat exchanger. There was a zinc on the heat exchanger, one aft on the head and another on the starboard side of crankcase.
Hudsonian is offline  
Quote Quick Reply Share with Facebook
post #10 of 11 Old 08-22-2015
Junior Member
 
Join Date: Aug 2015
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Re: Pencil Zinc location for Yanmar 2GM

The problem here is the original poster simply said a 2GM. This engine has come in so many variations over the years. While Post number three indeed answered the original question for the engine specified, the conversation has drifted.

The 2GM raw water cooled (sea or fresh water pumped in from the body of water the boat is in) does have two zincs. The 2GM20F, fresh water cooled (as in antifreeze and water that is changed annually) does not have any zincs on the engine nor the heat exchanger(as confirmed by the dealer when I returned the zincs I had bought without fully identifying my engine).

If you add a Sen-Dure heat exchanger, an after market addition made for many different engines, it may or may not have a zinc since they make both copper (zinc required) and Cupronickel (no zinc required) models.

The Yanmar 2GM20F heat exchanger is made of cupronickel. According to Wikipedia, "Cupronickel or copper-nickel is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater. Because of this, it is used for piping, heat exchangers and condensers in seawater systems..."

Hope this helps those that were as confused as I was.

Last edited by GansettSailor; 08-22-2015 at 04:16 PM.
GansettSailor is offline  
Quote Quick Reply Share with Facebook
Reply

Tags
yanmar zinc

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Yanmar 2GM HELP loup30s Diesel 12 02-17-2012 11:50 PM
Zinc pencil on Yanmar 3GM30F jgsteven Gear & Maintenance 17 11-14-2011 09:45 AM
Yanmar 2GM zfactor Boat Review and Purchase Forum 5 06-08-2009 10:00 AM
location of pencil zinc on Yanmar saildrive SD50 levenezia Gear & Maintenance 2 04-18-2009 09:07 PM
Looking for a Yanmar 2GM knotslo General Discussion (sailing related) 4 03-04-2009 07:12 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome