Possible Galvanic Corrosion?

[TruDaddy]

I opened my doghouse today and i noticed that my carb, fuel pump , and alternator pulley had what appears to be corrosion going on. I have a few questions:

• Is this corrosion?
• Can i simply clean it up and possibly seal?
• How can I fix prevent?

Boat Specs:

• 1989 Sea Ray 200BR
• Mercruiser 4.3LX
• Alpha One Drive Unit
• What else is needed for assistance?

 

[harringtondav]

Looks like corrosion. Make sure your drive zincs are good, and the ground wire between the transom plate and engine is connected & clean.

 

[TruDaddy]

The zincs are going on their second year. How often are those supposed to be replaced? I will check the wire/ground connection. Are there any addition grounds or wire related issues I should check?

 

[harringtondav]

My boat has been in fresh water for 22 years, and mine are still good. But they need to be tight & in good contact. There is another ground wire between the steering arm and transom plate

 

[TruDaddy]

Assuming it is just topical can I just clean those up and coat with something? Or is coating pointless?

 

[Bondo]

Assuming it is just topical can I just clean those up and coat with something? Or is coating pointless?

Ayuh,..... I believe yer just seein' corrosion from a moist environment, not galvanic corrosion,....

That said,.... Clean up the stuff, 'n paint 'em with something like Rustoleum industrial enamel to stop it from happenin' again,.....

 

[dingbat]

The zincs are going on their second year. How often are those supposed to be replaced?

The anodes should be changed when 1/2 consumed.
You should be running magnesium or aluminum anodes in freshwater.

 

[garbageguy]

+1 on the above (bondo's post).

Does your boat sit in an environment with moist (salty?) air? How often is the boat used, how often is the doghouse opened?

 

[harringtondav]

You should be running magnesium or aluminum anodes in freshwater.

I used zinc because I heard a gray beard member use the term, and it rolls of the tongue easier than 'Sacrificial Anode'. Mine are Merc. original, and have only generated a little dusty sacrifice in 22 yrs of fresh water use. I assumed they are alum., but only worry about their being tight.

 

[TruDaddy]

+1 on the above (bondo's post).

... How often is the boat used, how often is the doghouse opened?

This is a good point. My winterized canopy failed slightly allowing the more than usual Spring rainfall into my boat more than usual and it sat for a longer than usual. I bet the closed doghouse is the main culprit. I will clean, coat, and check all ground connections. Thanks all.