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Old 11 September 2008, 18:52   #1
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Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
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Lower Leg Aids ?

Hello

This engine used in salt water has been experimenting some strange problems, looks as a surface primer base & paint corrossion and maybe has reached metal already. The engine is completely rinse with fresh water and water flushed with engine on for about 10 minutes. The corrossion is begining to appear at the tail lower ground nut and engine water indicator & exhaust water port.

All anodes are in good shape have been removed and sanded for a better contact, were found not full of salt and still making good contact, will remove cable grounding to have a look, maybe doing a poor electrical contact from engine body to lower leg.

Would appreciate any ideas, thoughts about this kind of problem and what to do ?

Happy Boating
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Locozodiac is offline   Reply With Quote
Old 12 September 2008, 08:47   #2
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Country: USA
Town: Oakland CA
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Well, I'd say it's definitely surface corrosion under the paint, but I couldn't tell you what's causing it. Sounds to me like you're doing everything right.

jky
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Old 12 September 2008, 13:25   #3
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Country: Other
Town: Lima-Peru
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Engine: Tohatsu 18 /30 HP
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Quote:
Originally Posted by jyasaki View Post
Well, I'd say it's definitely surface corrosion under the paint, but I couldn't tell you what's causing it. Sounds to me like you're doing everything right.

jky
Thanks JKY, will remove engine lower leg ground cables and have a look, sand them and see if the corrosion continues, would you advise to sand the 2 problem parts, base primer and repaint ?
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Old 12 September 2008, 16:47   #4
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Country: Other
Town: Lima-Peru
Boat name: Nautile
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Length: 4m +
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Join Date: Sep 2007
Posts: 764
Have removed all ground cables and bolts, bolt threads were a little fouled with salt, have cleaned with thinner all bolst & engine bolts threads, greased well threads, adjusted bolts back, will see if the corrosion continues or stops there.
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Old 12 September 2008, 19:44   #5
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Country: Ireland
Town: Dublin & Enniscrone
Boat name: K'adó
Make: Redbay
Length: 7m +
Engine: Suzuki 300
Join Date: Oct 2004
Posts: 603
weight of anodes

Locozodiac

Be not decieved by the surface of the anodes. I am told the big thing is the weight of the anodes. Sometimes they look all right but will have shed a lot of their weight and are effectively useless. If in doubt replace.

Have you had someone check for leakage of corrent from your electrical system?

Best of luck.
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Old 14 September 2008, 14:24   #6
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Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 764
Quote:
Originally Posted by Ezgoing View Post
Locozodiac

Be not decieved by the surface of the anodes. I am told the big thing is the weight of the anodes. Sometimes they look all right but will have shed a lot of their weight and are effectively useless. If in doubt replace.

Have you had someone check for leakage of corrent from your electrical system?

Best of luck.
Ez, Anodes are perfect, no difference with new ones, not even hard corroded, just slight normal wear that look like brand new after the sanding work to justify a change.

Is there a method to check/look for this current leakage, the engine is performing at it's best at all throttle range. Will see if after the anodes and ground clean up, the corrosion continues. Thanks
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Old 16 September 2008, 19:25   #7
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Country: Other
Town: Labutes City
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Length: 3m +
Engine: Yamaha 25
Join Date: Aug 2008
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Hello
I Am new to the forum but not new to boats.
I live in portugal and work at a cobalt/jeaunau powerboats importer, and I see this tipe of problem every day especialy on inboards and sterndrives.

I have found this problem quite often with outboards( especialy with older suzuki's)
Check if you have alot of stainless parts in the water near the engine, Weaker metal erode much quiker, check to see if you have the correct anoedes recomended by the manufacture. There are 3 types.
The other problem is bad aluminum and bad painting/plating process.

I now you can take measuments of the electrical current around the boat to check for bad continuaty or possible current loss or excess or current. Have done it several times on Mercruiser drive units.

Cumps Fernando
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Old 16 September 2008, 21:12   #8
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Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 764
Quote:
Originally Posted by tsnando View Post
Hello
I Am new to the forum but not new to boats.
I live in portugal and work at a cobalt/jeaunau powerboats importer, and I see this tipe of problem every day especialy on inboards and sterndrives.

I have found this problem quite often with outboards( especialy with older suzuki's)
Check if you have alot of stainless parts in the water near the engine, Weaker metal erode much quiker, check to see if you have the correct anoedes recomended by the manufacture. There are 3 types.
The other problem is bad aluminum and bad painting/plating process.

I now you can take measuments of the electrical current around the boat to check for bad continuaty or possible current loss or excess or current. Have done it several times on Mercruiser drive units.

Cumps Fernando
Thanks Fernando for the imput, a relief to read that this is kind of "comon/normal" issue to happen to outboards & stern drives, in my case all 3 anodes are factory originals with just 1 constant year engine use, prob a bad quality plating/painting on that area. Will sand, prime and repaint that area.

Is there a way to check current loss or too much of it, please advise method to check.

Happy Boating
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Old 16 September 2008, 23:01   #9
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Country: Other
Town: Labutes City
Make: bombard
Length: 3m +
Engine: Yamaha 25
Join Date: Aug 2008
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Quote:
Originally Posted by Locozodiac View Post
Thanks Fernando for the imput, a relief to read that this is kind of "comon/normal" issue to happen to outboards & stern drives, in my case all 3 anodes are factory originals with just 1 constant year engine use, prob a bad quality plating/painting on that area. Will sand, prime and repaint that area.

Is there a way to check current loss or too much of it, please advise method to check.

Happy Boating
It“s not normal to happen, the aluminum will just rot away or get pourous!!! Be carefull and try to treat and find the cause,

What is happening is this
http://en.wikipedia.org/wiki/Galvanic_corrosion

Dont now if it is possible to read any galvanic currentwith a small outboard
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