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Honda 225 Exhaust Anodes longevity

chawk_man

Silver Medal Contributor
This is just a piece of information for y'all. Before my scheduled back surgery on 17 July, I took my boat to my dealer and had him pull the 400 hour maintenance and check several other items not on the maintenance schedule. One of those was the exhaust anodes. Yesterday, he told me that the anodes were still serviceable, but showed considerable wear. So he is replacing them. This is after 1600 hours of constant saltwater use, but a fresh water flush after every use. Boat is stored on a lift when not in use, except for two months or so in the winter at Hatteras.

Just thought this was a good data point for other 200/225 owners.
 
That's good to know Bill, did you replace them with original aluminium anodes or the more sacrificial zinc pattern ones?

Bob
 
Aluminium Anodes ?? i never seen it. zinc is the best active mettle for sea.

BF 225 got 4 small Zinc anodes in exhaust manifold 2 pcs in the lower unit 1 big pcs under the trim unit.

BF 250 got 4 small zinc anodes in the exhaust manifold 6 pcs in the sides of block 2 under the block.and big 3 pcs same in lower unit and under trim unit.

those small anode should replace every 1000 hrs or 2 years.
it is better to replace them then only can protect the engine from corrosion.



wajira
 
I presume all genuine Honda anodes are aluminium as they are a lot lighter than zinc anodes, and seem to last well.
Some aftermarket/pattern part anode manufacturers offer the option of aluminium or zinc(for salt water) or magnesium (for fresh water), but zinc seems most commonly sold by these non-genuine manufacturers.
here are the specs and charcteristics
http://www.freedomlift.com/pdfs/Aluminum Anodes.pdf

Bob
 
That's a very interesting article. Thanks for sharing.

I assumed the dealer who is doing the work is installing zinc anodes in the manifolds. However, when I pick up the boat I will confirm that and let you all know. I do know that the external anodes are all zinc. So, given the caution in the article to never mix anode types, it's logical that the internal anodes are also zinc.
 
I thought the factory anodes were aluminum. I replaced mine and they didn't look like zinc, and they were oem.
 
I'd be surprised if they mixed anode types, but let's see what the dealer says when I get my boat back - the folks I use are VERY experienced and very good - Whelan's Marina in Farmham, VA.
 
OK all got 2450 hrs on my 2002 225 HP . Our these exhaust anodes hard to get to ? Would I be able to change out myself ? Chawk got me worried if you didn't do yourself ? I see another winter project coming

Thanks
Jamie
 
Jamie,

You can definitely do it yourself. Disconnect the hoses on the exhaust manifolds and move a couple things out of the way, then unbolt each manifold. The anodes are inside and held on with philips screws. I had to use an impact driver to break them loose but did get them out. Make sure you buy the anodes for each side, the seals at the bottom of the manifolds, manifolds gaskets, and I would suggest buying the screws that hold the zincs, to save you some time trying to get them free from the zincs and cleaned up.
 

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Jamie - didn't mean to get you worried. I had back surgery scheduled, so before going under the knife I took my boat to the dealer and had him pull a 400 hour maintenance plus check out a bunch of other things that I would not have the time and inclination to handle anytime soon. One of those was to pull the exhaust manifolds and check the state of the anodes. That's why I started this post.

Ep4 gave you the correct procedure - see pages 5-117 to 5-119 in the Helm shop manual. It gives the step-by-step procedure. To re-enforce what he said, replacing the seal (big O ring) on the bottom of each manifold is real important.

Anyway, I think it would add to the info on this thread if you do the replacement, post the state of the anodes after 2500 hours. It would be a nice second data point.
 
Well folks, I picked up my boat yesterday and asked about the replacement exhaust anodes. They thought they were zinc, but were not sure, saying they were simply the OEM replacements. They gave me a box with all the old parts that were replaced, and I dug out the old anodes. They definitely were highly corroded. BUT, they were also very light, more like aluminum instead of zinc. I'm going to cut one in half today and see if I can make a definitive determination.

They also said something to the effect: "I just don't understand those Japanese anodes - instead of just eating away like regular anodes, they just seem to stop working at some point." That statement is more consistent with the way aluminum anodes act instead of zinc. So it looks like there is a distinct possibility that those exhaust anodes are, indeed, aluminum. Surprise, Surprise!
 
Just a follow-up. Those four anodes inside the exhaust manifolds are definitely aluminum alloy. I cut one in half and inspected it closely. Besides being much lighter in weight than an equal amount of zinc, once I cut through it, you could easily see the aluminum metal.

I imagine that Honda is using the aluminum alloy anodes because they work reasonably well in all applications saltwater, brackish, and fresh - and last about 50% longer than zinc.

The anodes that were removed did not show a lot of structural deterioration after 1600 hours, unlike what you would expect from a zinc anode. However, the aluminum anodes were extremely light - more than one would expect from a standard piece of aluminum of the same size. I suspect that these anodes deteriorate internally and may just stop working without showing the wasting away we are all used to seeing from zinc anodes.

I would like to hear from folks who have had a lot of experience with the aluminum alloy anodes to see if my speculation is true about difference in wasting appearance.
 
Lots of good information here guys.
I have a 06 bf225 with 2000 hrs.
Will be changing manifold anodes next service.
Have read the honda workshop manual on this and it stated to loosen off the 8x 30 ,8x100 , 6x 120 flange bolts to the water jacket prior to lightening the manifold bolts when befitting the exhaust manifolds.
Is this necessary of is it just another example of the workshop manual making things more painful than need be.
Any advise from the techs or guys that have done this before much appreciated
 
It's my understanding that you loosen the bolts on the water jacket in order to get the manifold back into it's seat easily and correctly with a new O ring. I've not had to do this myself, so just speculation.
 
It's my understanding that you loosen the bolts on the water jacket in order to get the manifold back into it's seat easily and correctly with a new O ring. I've not had to do this myself, so just speculation.



Thank you chawk_man,makes perfect sense the way you descibe so the manifolds bottom out on their seat .
Is there a seal on the the water jacket that will need to be replaced if I undo the flange bolts ?
 
Not sure. The manual says to not reuse, but is says that about every gasket and seal. Personally, I would error on the side of caution and replace them.
 
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