Lower Unit Pitting

[Solittle]

It is time to paint my 17 year old OMC V-4s. I removed the deacals just above the cavitation plate and there was some moderate pitting in the metal. It is relatively easy to scrape off the surface corrosion but impossible to get the crud out of the pitted areas. These are salt water motors and the crud is like a caked on white powder.<br /><br />Is there a chemical that will clean it out so that the new paint will adhere?

 

[Bradster941]

Re: Lower Unit Pitting

Kwik Tek makes such a product. Spray on, rinse off.<br />Available through Land n Sea in Pompono.<br />Part number 253-SX10 is a 10 oz. spray bottle.<br /><br />Keep in mind once clean, you'll need to use an aluminum primer such as zinc phosphate chromate.<br /><br />I have to wonder why they are so pitted?<br /><br />Do you leave it in the water?<br /><br />One major mistake people make is when they bottom paint their boat with anti fowling paint, they use the same paint on their lower units.<br />This is a big No No as that paint for the hull has copper in it. When applied to the aluminum lower unit, electrolysis starts and since the copper is denser than the aluminum, the aluminum breaks down causing the pitting you described.<br /><br />They do make a anti fowling paint for aluminum, available most anywhere.<br /><br />Hope this helps.<br /><br />

 

[Solittle]

Re: Lower Unit Pitting

Bradster - Do you have the name of the product you mentioned and either a web site address or a phone number for Land n Sea?<br /><br />Nice job on your motor. I have a pair of 1987 1.6L SeaDrives on the back of my 1988 23' Wellcraft CC. Great rig!<br /><br />My motors have never seen bottom paint. My rig sits on a trailer & I have had it for 10 yrars. The pitting started underneath the decal that is just above the cavitation plate. The corrosion is not real bad but if I'm going to the trouble of painting it I want the paint to stick.

 

[Bradster941]

Re: Lower Unit Pitting

Land n Sea<br />3131 N. Andrews Ave. Extension<br />Pompano Beach, FL 33064<br />954 792-5436<br /><br />SoLittle, I'm not sure if they will sell over the counter, they are a wholesale supply house.<br />If not, any of your local marine shops should be able to order it for you.<br /><br />You might also do a search here on iboats. Not sure if they cary it or not?... <br /><br />Since you trailer your boat, you won't need the anti fowling paint.<br /><br />By the way, how is the Dolphine fishing in your area right now? Was thinking about going to the Keys next weekend...<br /><br />

<br /><br /><br />

 

[Solittle]

Re: Lower Unit Pitting

Thanks Brad - Can't help with the Dolfin as I'm not a fisherman. When serloin steaks grow fins I'll go buy a pole.

 

[quantumleap]

Re: Lower Unit Pitting

Several soakings of vinegar will remove the deposits that you describe.