# Corrosion on outboard from salt water -paint help



## Mako22 (Feb 8, 2013)

The paint on my 2003 Johnson 25HP outboard is flaking off and has been for about 4 years now. I believe this is due to salt water even though I have always rinsed the boat, trailer and motor off after each salt water use. What I want is advice on how to stop the corrosion and how to repaint the bare surfaces. I'm not looking for a professional looking solution just info on how do I treat and repaint to stop any further corrosion? I'm not really concerned with how a home repaint job would look I just want to protect the motor.


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## 1gr8bldr (Feb 8, 2013)

Is it grounded? This will sound strange but it is true. If you look on outboards, they have a lead looking piece mounted on them for this purpose. I can't explain this. A little research and you will see that it is a big deal as far as corrosion. I studied it years ago but have forgotten the reasons


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## 1gr8bldr (Feb 8, 2013)

google "pro troll" it talks about your boats charge. Is your zinc [lead looking] thing on the foot missing?


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## 1gr8bldr (Feb 8, 2013)

Z, edit; tried to post a pic from another site. did not work


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## 1gr8bldr (Feb 8, 2013)

Here is the caption but sorry, no pic; Zinc annodes are installed on outdrives or motor shafts to protect from electrolytic corrosion. Note the heavily corroded condition of this zinc. When the zinc is more than 50% corroded, it should be replaced.


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## Lukikus2 (Feb 8, 2013)

^^^^^^^

They are correct what caused it. Your sacrificail anode on the motor needs to be replaced. And make sure you don't paint over it.

Any good boating outlet will have the paint for your motor (like West Marine). Just be sure and strip it good if not bead or sandblast it good. I would suggest the whole motor because it's already under the other paint just not visible yet. You can buy the primer and paint at those outlets. A little more expensive but worth it.


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## 1gr8bldr (Feb 8, 2013)

Lukikus2 said:


> ^^^^^^^
> 
> They are correct what caused it. Your sacrificail anode on the motor needs to be replaced. And make sure you don't paint over it.
> 
> Any good boating outlet will have the paint for your motor (like West Marine). Just be sure and strip it good if not bead or sandblast it good. I would suggest the whole motor because it's already under the other paint just not visible yet. You can buy the primer and paint at those outlets. A little more expensive but worth it.


That is a good description.


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## dawg2 (Feb 8, 2013)

You need new sacrificial anodes.  NO paint and they need to contact raw metal.


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## Mako22 (Feb 8, 2013)

Wow I never knew that and I have been running salt water for 20 years.


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## Mako22 (Feb 9, 2013)

Well my anode looks pitted and worn to me so I will be looking to replace it soon. I just wish I had learned this 10 years ago. I have always been careful about my boat in salt water and have always rinsed it off all over with a garden hose after each trip. Now I'm worried about my boat hull since this thread spurned me to do some reading on aluminum boats in salt water. Thanks for the advice.


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## dawg2 (Feb 9, 2013)

You can also accelerate corrosion by not having it grounded properly.  If you ever plug into marina power and another boat has electrical problems, you are now in the same situation as the "bad" boat and will get damage on YOUR boat.  Look up "hot marina."  Also look up "stray current corrosion."  Your case can probably be solved by making sure you have good clean electrical connections, proper grounding and new sacrificial anodes.


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## dawg2 (Feb 9, 2013)

Woodsman69 said:


> Well my anode looks pitted and worn to me so I will be looking to replace it soon. I just wish I had learned this 10 years ago. I have always been careful about my boat in salt water and have always rinsed it off all over with a garden hose after each trip. Now I'm worried about my boat hull since this thread spurned me to do some reading on aluminum boats in salt water. Thanks for the advice.
> 
> View attachment 715017



Also, look up your motor on line and find the owners manual.  It will show you where the anodes are located.  Many motors have more than one.  Lots of times previous owners have removed them and never replace them.


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## Bilge Rat LT 20 (Feb 12, 2013)

Replace anodes.
When the boat is not being used disconnect the the power  or if it has a battery disconnect switch make sure it is turned off. Stray voltage causes damage like yours.

When you paint the motor use zinc chromate primer.


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