Yanmar 3GM30F Engine Electrolysis

Xtofinooic · 25-03-2008, 13:10

Hi, I recently picked up a Hunter with a Yanmar 3GM30F eng. The eng is equipped with a heat exchanger. So it is running fresh water in the engine and Salt water is supplied to the heat exchanger for cooling. My concern is that there are no zinc anodes in the heat exchanger where there are a number of dissimilar metals and saltwater. As this is a recipe for Electrolysis I was wondering has anyone experienced this problem with this type of eng. The only way to remedy this that I can think of is to custom build a end cap for the heat exchanger that can accommodate an anode without interfering with the core.
Also, The manual is not very clear but seems to indicate that the engine block zincs (2) and the eng. head zinc (1) are not used when the eng. is fresh water cooled. This makes sense to me. It does not make sense that the heat exchanger does not have a place for a zinc .

By Invitation · 25-03-2008, 13:15

I am not an expert on this particular engine but I do seem to recall a similar thread discussing this exact same issue with some Yanmar engines.
Gord May most likely will give you some kind of a link to this issue - it's what he does and he does it well.

roverhi · 25-03-2008, 14:17

Yanmar uses cupronickel heat exchangers. Extremely low to non existant corrosion factor so no zincs fitted. Most engine mfg use copper heat exchangers which need a zinc to keep corrosion at bay.

Aloha
Peter O.

never monday · 25-03-2008, 15:16

If it needed a zinc, Yanmar would have designed an end cap to use one. There are many thousands of these engines in use and none have internal corrosion problems.

Inlet Marine Services · 25-03-2008, 17:27

Dont overthink the issue, Yanmar does not use a zinc in any fresh water cooled small hp motor

Chief Engineer · 25-03-2008, 20:36

All to often, owners are their own worst enemies when it comes to "re-engineering" things......

One of my favorites is the guy who put two racors (500 series) in-line along with an algae-x on a 1GM Yanmar.....

Quote:

Originally Posted by Inlet Marine Services

Dont overthink the issue, Yanmar does not use a zinc in any fresh water cooled small hp motor

GordMay · 26-03-2008, 03:15

There’s numerous CruisersForum discussions about Yanmar Zincs, which can be searched at “Google Cruisers & Sailing Forum” (type yanmar zinc): Cruisers & Sailing Forum

As others note, I've never experienced any corrosion problem with my 2GMF, sans zinc.

Xtofinooic · 26-03-2008, 06:18

Thanks all for the info. Glad to hear that the cupronickel alloy in the heat exchanger doesn't appear to require zincs. My fears have been put to rest.

25-03-2008, 13:10	#1
Xtofinooic Registered User Join Date: Mar 2008 Location: Salt Spring Is. BC, Canada Boat: Hunter 35.5 "Irie" Posts: 4	Yanmar 3GM30F Engine Electrolysis Hi, I recently picked up a Hunter with a Yanmar 3GM30F eng. The eng is equipped with a heat exchanger. So it is running fresh water in the engine and Salt water is supplied to the heat exchanger for cooling. My concern is that there are no zinc anodes in the heat exchanger where there are a number of dissimilar metals and saltwater. As this is a recipe for Electrolysis I was wondering has anyone experienced this problem with this type of eng. The only way to remedy this that I can think of is to custom build a end cap for the heat exchanger that can accommodate an anode without interfering with the core. Also, The manual is not very clear but seems to indicate that the engine block zincs (2) and the eng. head zinc (1) are not used when the eng. is fresh water cooled. This makes sense to me. It does not make sense that the heat exchanger does not have a place for a zinc .

25-03-2008, 15:16	#4
never monday Commercial Vendor Join Date: Jun 2005 Posts: 1,442	If it needed a zinc, Yanmar would have designed an end cap to use one. There are many thousands of these engines in use and none have internal corrosion problems. __________________ www.inlandmarinediesel.com

26-03-2008, 03:15	#7
GordMay Registered User Join Date: Mar 2003 Location: Thunder Bay, Ontario - 48-29N x 89-20W Boat: C.L.O.D. (Cruiser Living On Dirt) Posts: 12,576	There’s numerous CruisersForum discussions about Yanmar Zincs, which can be searched at “Google Cruisers & Sailing Forum” (type yanmar zinc): Cruisers & Sailing Forum As others note, I've never experienced any corrosion problem with my 2GMF, sans zinc. __________________ Gord May ~~_/)_~~ (Gord & Maggie - "Southbound") "If you didn't have time/$ to do it right in the first place, when will you get the time/$ to fix it?"

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Yanmar 3GM30F	Badsanta	Engines and Propulsion Systems	37	07-04-2008 20:59
Yanmar 3GM30F - followup-IP/cutoff cable	calphi27	Engines and Propulsion Systems	1	05-09-2007 12:10
Yanmar 3GM30F Raw Water Intake Size	Cadence10m	Engines and Propulsion Systems	8	15-11-2005 00:31
Yanmar Engine Zincs	Strygaldwir	Engines and Propulsion Systems	9	15-02-2005 11:55

25-03-2008, 13:15	#2
By Invitation Registered User Join Date: Feb 2005 Location: Wakefield Rhode Island Posts: 266	I am not an expert on this particular engine but I do seem to recall a similar thread discussing this exact same issue with some Yanmar engines. Gord May most likely will give you some kind of a link to this issue - it's what he does and he does it well.

25-03-2008, 14:17	#3
roverhi Registered User Join Date: Aug 2005 Location: Kona, Hawaii Boat: Pearson 35 #108 Posts: 739	Yanmar uses cupronickel heat exchangers. Extremely low to non existant corrosion factor so no zincs fitted. Most engine mfg use copper heat exchangers which need a zinc to keep corrosion at bay. Aloha Peter O.

25-03-2008, 17:27	#5
Inlet Marine Services Commercial Vendor Join Date: Jan 2008 Location: Olympia, WA Posts: 73	Dont overthink the issue, Yanmar does not use a zinc in any fresh water cooled small hp motor

26-03-2008, 06:18	#8
Xtofinooic Registered User Join Date: Mar 2008 Location: Salt Spring Is. BC, Canada Boat: Hunter 35.5 "Irie" Posts: 4	Thanks all for the info. Glad to hear that the cupronickel alloy in the heat exchanger doesn't appear to require zincs. My fears have been put to rest.