Bravo 3 anodes and mercathode

pursuit2460

Petty Officer 2nd Class
Joined
Aug 24, 2004
Messages
189
So, I recently did a outdrive shift cable change and replaced all the o-rings on the lower and upper units. At the same time I bought the Anode kit which was the 2 rams, front/rear lower anodes. I took it out yesterday for the first time with the new anode. When I came back, I was hosing down the outdrive and noticed that the anodes already had some white to them. I have read on the issues of the B3 and the corrosion issues. I do not have Mercathode system, but there was one previously, I see the wiring. Boat is also trailered, never stays in the water. Unless the rarely over night stay at an island.
 
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pursuit2460

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04fxdwgi25

Chief Petty Officer
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Mar 25, 2022
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2 questions:
1. what kind of water you boating in. Salt, brackish or fresh
2. What material are the zincs. Zinc, aluminum, magnesium or a combination?
Zincs need to matched to the type of water it is normally in.

Suggest having the Mercathode installed, as the B3's are brutal when it comes to corrosion
Also, verify all your bonding wires are installed per the manual and connections are tight and clean.

My B3 shows barely any zinc degredation in the past year. A little white fluff is normal.
 

pursuit2460

Petty Officer 2nd Class
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Aug 24, 2004
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189
2 questions:
1. what kind of water you boating in. Salt, brackish or fresh
2. What material are the zincs. Zinc, aluminum, magnesium or a combination?
Zincs need to matched to the type of water it is normally in.

Suggest having the Mercathode installed, as the B3's are brutal when it comes to corrosion
Also, verify all your bonding wires are installed per the manual and connections are tight and clean.

My B3 shows barely any zinc degredation in the past year. A little white fluff is normal.
Salt. As for the anode material, it came in a 100HR Mercury kit, anodes and some o-rings. I did some searching and it seems they are aluminum. I have all the bonding wires, but the Mercathode is missing. I have read that trailered boats don't really need it. But this is my first B3 so I have no idea. I do know of the serious corrosion issues. I just bought a prop anode also from Boatzincs. My B3 is a 2000, so it didn't come with one like the newer B3s.
 

04fxdwgi25

Chief Petty Officer
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Mar 25, 2022
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Sounds like all is in order. Give it a little time and see if they degrade.

My boat is trailer boat also, but have the Mercathode on it. Can't hurt to have a little extra insurance, especially as costly as the B3 is.

One caviat, does you cav plate have 1 or 2 zincs on it. Mine has 2 since PO replaced the case and had drive rebuilt and has the newer style plate, but the original internals.

I tried that add on prop anode, too, but couldn't get it to fit properly
 

pursuit2460

Petty Officer 2nd Class
Joined
Aug 24, 2004
Messages
189
Sounds like all is in order. Give it a little time and see if they degrade.

My boat is trailer boat also, but have the Mercathode on it. Can't hurt to have a little extra insurance, especially as costly as the B3 is.

One caviat, does you cav plate have 1 or 2 zincs on it. Mine has 2 since PO replaced the case and had drive rebuilt and has the newer style plate, but the original internals.

I tried that add on prop anode, too, but couldn't get it to fit properly
My cav plate has one on the top side in the rear, closet to the transom. It also has one on the underside by the props. 1st and 3rd pics that I posted are the cav plate anodes. Here is the link to the prop anode.
 

pursuit2460

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Ok. So I did some more reading and it seems that the Mercathode system is useless on trailered boats. The system only works while the boat is in a wet slip. There has even been talk about it being less affective if there is a water current where the boat is slipped as this makes the "protection" be washed away. I found a Mercury service bulletin explaining some of the test you can do. It mentions in one of the test that the boat has to be in the water for at least 8 hours. Then when you board the boat, to try to rock it at least as possible because rocking it will give inaccurate readings.
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,322
Aluminum is for salt and freshwater. You are okay with the material and noting that the anodes are working.

Zinc will last longer but is only for salt water, spend a little more but get protection longer if you only cruise salt

Mercathode system works great, feel free to install it for extra protection but the main focus for the mercathode system is for moored boats. Helps protect against stray current from other boats/shore power issues
 

pursuit2460

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Aug 24, 2004
Messages
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Aluminum is for salt and freshwater. You are okay with the material and noting that the anodes are working.

Zinc will last longer but is only for salt water, spend a little more but get protection longer if you only cruise salt

Mercathode system works great, feel free to install it for extra protection but the main focus for the mercathode system is for moored boats. Helps protect against stray current from other boats/shore power issues
I have an issue understanding the Mercathode system. You’re saying to install it for extra protection but from what I have read it does nothing for a trailered boat. My boat isn’t moored. So why install it? As for the anodes, I had done some reading to make sure I got the right one. Are you sure zinc last longer? Everything I read said the opposite, aluminum last longer. Anyways, I have never seen my anodes on my outboards turn so quickly. I guess it has to do with the B3 and their corrosion issues.
 

dubs283

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Jul 27, 2005
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5,322
If you're only salt water, zinc is best

If you're 50/50 salt/freshwater, aluminum is best

If you're freshwater only, magnesium is best

Add the mercathode for extra protection of you want. Explanation was for others to understand fully the purpose of the mercathode system
 

tank1949

Lieutenant Commander
Joined
Apr 4, 2013
Messages
1,893
So, I recently did a outdrive shift cable change and replaced all the o-rings on the lower and upper units. At the same time I bought the Anode kit which was the 2 rams, front/rear lower anodes. I took it out yesterday for the first time with the new anode. When I came back, I was hosing down the outdrive and noticed that the anodes already had some white to them. I have read on the issues of the B3 and the corrosion issues. I do not have Mercathode system, but there was one previously, I see the wiring. Boat is also trailered, never stays in the water. Unless the rarely over night stay at an island.
I don't put much faith in Mercathode. However, I don't leavy my boat in salt water. They will suck a battery down if you don't have shore power and good battery charger. I have a Bravo 1 and my zinks look like yours.
 

04fxdwgi25

Chief Petty Officer
Joined
Mar 25, 2022
Messages
539
My cav plate has one on the top side in the rear, closet to the transom. It also has one on the underside by the props. 1st and 3rd pics that I posted are the cav plate anodes. Here is the link to the prop anode.
MY bad, should have been more specific on the cav plate. Mine has 2 round ones on the underside over the prop area, and the one forward on top.

Yeah, tried that prop nut zinc and it did not fit well. Took it back off, as I didn't want it to be wobbling around.
 

pursuit2460

Petty Officer 2nd Class
Joined
Aug 24, 2004
Messages
189
MY bad, should have been more specific on the cav plate. Mine has 2 round ones on the underside over the prop area, and the one forward on top.

Yeah, tried that prop nut zinc and it did not fit well. Took it back off, as I didn't want it to be wobbling around.
I will let you know how it works out for me.
 

tpenfield

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Staff member
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Jul 18, 2011
Messages
18,040
I'm a salt water guy. The anodes look fine to me. Deterioration means that they are working. You probably should get the Mercathode system, just for added protection.

Since you have only 1 ventilation plate anode (round), it indicates that you have the older B3. Add the prop anode and call it good.
 

pursuit2460

Petty Officer 2nd Class
Joined
Aug 24, 2004
Messages
189
I'm a salt water guy. The anodes look fine to me. Deterioration means that they are working. You probably should get the Mercathode system, just for added protection.

Since you have only 1 ventilation plate anode (round), it indicates that you have the older B3. Add the prop anode and call it good.
Didn’t know there was 2 of the round ones on the newer B3. I figured they were working, I just didn’t think they would change on day 1. I have replaced the anodes on my outboards before and never saw a change from day one. Prop nut is on its way. I am going to skip the Mercathode system. It only works if the boat is moored. My boat is trailered so it wouldn’t do anything to help.
 

ROY WILLIAMS

Chief Petty Officer
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Aug 8, 2022
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400
So, I recently did a outdrive shift cable change and replaced all the o-rings on the lower and upper units. At the same time I bought the Anode kit which was the 2 rams, front/rear lower anodes. I took it out yesterday for the first time with the new anode. When I came back, I was hosing down the outdrive and noticed that the anodes already had some white to them. I have read on the issues of the B3 and the corrosion issues. I do not have Mercathode system, but there was one previously, I see the wiring. Boat is also trailered, never stays in the water. Unless the rarely over night stay at an island.
I was the small wire brush anodes cleaned it .....
the aluminum outdrive painted it ....
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,444
Didn’t know there was 2 of the round ones on the newer B3. I figured they were working, I just didn’t think they would change on day 1. I have replaced the anodes on my outboards before and never saw a change from day one. Prop nut is on its way. I am going to skip the Mercathode system. It only works if the boat is moored. My boat is trailered so it wouldn’t do anything to help.
Yeah they added a second round one to the later bravo 3 because of the corrosion issues seen on the early B3s. they can corrode inside the prop hub where bearing carrier goes in and housing cracks. Happened to a friend of mine in northern Chesapeake which is slightly brackish water. His is slip kept but i wouldn’t discount using a mercathode as it will protect yours while in the water. it is my understanding that the big dual stainless props create some cathodic current while spinning. You may be seeing this by the fast change on your annodes…would just keep an eye on it and remove props to check hub area.

my own experience is with an alpha gen 2 , lift kept boat ( at end of private dock not in marina) on fresh water. On my old boat always ran aluminum props never had any anode wear… never changed anodes in 20 years, never needed to… new boat i got seven years ago noticed a little corrosion when running a Vensura prop. Five years ago switched to a Revolution 4 which is a much bigger heavier piece of SS. Immediately noticed some corrosion around prop hub and annode wear... switched out annodes twice found oem merc seemed to get best results, and added a mercathode. This seems to have stopped corrosion development.

bottom line keep and eye on it as if i can get corrosion in nice fresh water with a big single SS prop you may have an issue given the history of B 3 corrsoion
 
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