Alpha One corroding in the water

[Evinrude Boater]

When I bought the boat last year the outdrive was corroded so I painted it up and installed a new anode. It corroded again, prop, gear case and rams. I checked continuity between everything on the water side and it was all connected so I cleaned the bottom paint off the hull around the outdrive hoping that was the problem and painted the outdrive again with Mercury Phantom Black enamel. It's still corroding. What should I check next in the water or out of the water?

 

[Ruddell]

Re: Alpha One corroding in the water

What type of motor do you have? Is it a mercury with a MerCathode system?

When you said checked continuity on the water side, did you trace the grounding straps all the way back to the engine?

Also what type of water are you running in? Zinc, Aluminum, and in some cases Magnesium are available. They each have their own different applications.

Here's a link with some more information.
http://gulffishing.com/tips_anode.html

 

[Bt Doctur]

Re: Alpha One corroding in the water

Anybody on the side of you with shore power or a regular battery charger ???????

 

[Ruddell]

Re: Alpha One corroding in the water

Thats a good point Bt Doctur. Could be your motor becoming the sacrificial anode for someone else

 

[Evinrude Boater]

Re: Alpha One corroding in the water

Yes, it's a Mercruiser as in my signature line but no cathodic protection. I didn't check continuity all the way back to the engine, but I will. Is that possible now that it's sitting in the water?
The water is fresh water and the next boat is a couple of hundred feet away. It's a cottage area, not a marina. I don't know of anyone with shore power or anyone charging batteries.
I suspected it was a condition that was particular to this boat since it was corroded when I got it and it keeps occuring each time I put in the water for the season. The anode was missing when I viewed the boat so I put on a new one last year, I don't recall which type.

 

[rodbolt]

Re: Alpha One corroding in the water

use the mercury reference electrode and your DVM.
it will tell you if your anodes are under or over protecting.

 

[Don S]

Re: Alpha One corroding in the water

Here is the a Mercruiser service bulletin on checking and preventing corrosion.

http://www.4shared.com/document/ViLRp-nH/02-06_Corrosion_Prefention_and.html

 

[wire2]

Re: Alpha One corroding in the water

Don, do you happen to know specifically what the Quicksilver Reference Electrode (91-76675T1) consists of? I'm going to speculate that it costs more than I want to spend on a test.

 

[Evinrude Boater]

Re: Alpha One corroding in the water

I'm going to speculate that it costs more than I want to spend on a test.

Want to share?

 

[wire2]

Re: Alpha One corroding in the water

Want to share?

Good idea, but, we may need to find some more locals; I just called a T O Merc dealer, it's $160. Ouch!

 

[Evinrude Boater]

Re: Alpha One corroding in the water

All I could check tonight was continuity between the steering arm ground wire and the outdrive anode and trim cylinders and engine. There's continuity.