MerCathode

Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
I just purchased the Mercury Service Manual for my Bravo 3 drive. I was looking thru and I stumbled across the Mercathode information. I boat in fresh water and I get more than the average amount of corrosion on my drive. I am probably going to replace the electrode because I get the feeling that it has been painted by the PO of the boat. I also stumbled across an interesting statement, "In saltwater, a second MerCathode System blue controller may be added in parallel to increase protection to 400mA." I did the reference electrode test and I recall it being around 650mV in fresh water, which is low, and may be causing some of my corrosion issues. For the test, it gives you acceptable levels for fresh water and "Salt, Polluted, or Mineral Laden water". I have a feeling that the rivers that I boat in, The Allegheny, The Ohio and The Monongahela, are either mildly polluted or full of minerals. I do know that there is minerals in the water. I am wondering if I add a second MerCathode controller, would that give me the added protection that I need or would it be a waste of money.
2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
Go Steelers!!!

Comments

  • Handymans342Handymans342 Cape Coral, FLPosts: 4,635Member ✭✭✭✭
    I think Pittsburgh gets rain with the highest acid count on the country
  • TrashmanTrashman New Jersey/ philaPosts: 293Member ✭✭✭
    Try the new mercathode first.  Your old one may have had issues.  I did mine, it's tons of fun.   If you had corrosion issues I'd switch out the hydraulic manifold also.  The wire is quite difficult to fish through.  I used some weed whacker line as a fish tape.   I tied a string to the old one then pulled through but the string came off.   
  • StodgeStodge Lake St. ClairPosts: 1,119Member ✭✭✭
    @Cableguy Greg are you eating up anodes fast?  Could the issue be stray current in the area around your boat?

    2002 FV 342 on Lake St. Clair - Past Commodore SHC - Vessel Examiner USCGAUX

  • TrashmanTrashman New Jersey/ philaPosts: 293Member ✭✭✭
    Good point stodge. And what type?   Also there could be an issue with your grounding wires/ continuity 
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    They never go below 50% in a season. I have disconnected all of the boats at the end of the dock where my slip is at and the numbers never change. I am going to start with a new electrode and test the controller. I am sure that it will be FUN to pull the new wires thru with the engine in place. I do have a fiberglass fish tape, which make pulling wires on the boat easier.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    I use magnesium anodes, which are for fresh water.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • rasburyrasbury Sanford, FLPosts: 3,129Member ✭✭✭✭
    thank the lord I don't have to worry about this as I trailer my boat. I have no clue how all this stuff works!
  • frenchshipfrenchship Québec ,CanadaPosts: 1,053Member ✭✭✭
    Raz,
    even if you trailer your boat, has nothing to do with the mercathode or anodes, if you leave your boat in the water even for a week or a few days damages could happen specially in salt water.
  • rasburyrasbury Sanford, FLPosts: 3,129Member ✭✭✭✭
    @frenchship
    yes, I figure that....I don't see any corrosion on the foot anywhere except right where the lines for the trim go into a manifold of sorts- right there I have a little.  There is one other small area on the foot, I guess it is an exhaust area (?) where the paint had come off and I repainted it...right by the hex nuts that hold the lower and upper foot together. I guess I better start to figure this out, where do I start? I need something that would explain it to a 5th grader.....
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    I checked the electrode and it doesn't look to be in the greatest of shape. I will have to reference the manual to see how to test it before buying a new one. I am still considering adding another controller to beef up the system. My spring project list is growing...
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • Handymans342Handymans342 Cape Coral, FLPosts: 4,635Member ✭✭✭✭
    Greg, got a pic of that electrode?
  • rasburyrasbury Sanford, FLPosts: 3,129Member ✭✭✭✭
    Anyone know a good reading source that explains what the system does and what makes it work? I do not have a clue like I already stated....electrical and me do not speak the same language...
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    @Trashman, the Linkedin post confirms what I was thinking about adding a second controller. It also states about replacing anodes, which I will have to start doing twice a season. Mine were beyond the 25% threshold, but others recommend 50%.  I read the Service Manual #28 which is specific to my drive and that is where I got the idea about the second controller. I will grab a picture of the electrode sometime this week. It may or may not need replaced, or I should replace it for peace of mine.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • TrashmanTrashman New Jersey/ philaPosts: 293Member ✭✭✭
    @Cableguy Greg  glad that helped. I used magnesium anodes with what i think was a successful 5 month season. im in the delaware river and most at my marina use aluminum. I refinished my severly corroded outdrive at the beginning of the season(i have a discussion with many pics you can check out). I just replaced the mercathode and a new continuity kit on mine and im glad I did. 
  • rasburyrasbury Sanford, FLPosts: 3,129Member ✭✭✭✭
    Ouch, that makes my brain hurt..to long a day today to digest that Greg but thanks, will take a look...i only have a meter with the probes, so if I put the alligator clips on then , does that make the testing accurate?
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    Here are a couple of pics of the drive unit.


    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • Michael TMichael T Posts: 5,663Member ✭✭✭✭✭
    @Cableguy Greg. The reference anode test is inaccurate 95% of the time (past Mercury info sheet). If there is any current or slight wave action in/on the water the MAs under-report. The Mercathode module is easily damaged by being hit by anything. Mercuiser has acknowledged this. The system works great but is sensitive. You can gang two together but unless you are boating in the love canal you shouldn't have to. You have done your homework by checking for poor electrical grounds in the boats near you. Is your galvanoic isolator working well - knowing you, I assume you have checked that. I have never let my anodes go below 50%. IMO at less that 50% other surfaces start getting attacked.
  • HamdogHamdog Lee's Ford Marina, Lake Cumberland in KYPosts: 244Member ✭✭
    My anodes lasted 5 years. They were down to about 30% when I changed them. No damage. Magnesium in fresh water lake.
    "Wetted" Bliss 2005 Rinker 342 - Black Hull - Twin Mercruiser 350 Mags - BIII's
  • Handymans342Handymans342 Cape Coral, FLPosts: 4,635Member ✭✭✭✭
    Has anyone replaced their Mercathode Anodes?????
  • Handymans342Handymans342 Cape Coral, FLPosts: 4,635Member ✭✭✭✭
    Hey Greg, Nice steel leader drain plug! Complete with slime! LOL
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    My oil drain hose is on the other end of it. The small cable that connects to the drain plug fell apart so I have to replace it when I get home from Florida.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • Cableguy GregCableguy Greg Pittsburgh, PAPosts: 2,660Member ✭✭✭✭
    I replaced my mercathode anode today. It was a PITA. Hopefully it works better than the old one. The orange wire on the old one was shot.
    2008 280 Express Cruiser, 6.2MPI, B3, Pittsburgh, PA
    Go Steelers!!!
  • Handymans342Handymans342 Cape Coral, FLPosts: 4,635Member ✭✭✭✭
    No pics????
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