Lower Unit Corrosion

fredbrillo

Recruit
Joined
Mar 26, 2011
Messages
4
HI there....I have a 1994 Pro50 Yamaha on a Boston Whaler....Recently I noticed some corrosion spots on the lower unit....about the size of a quarter...one on each side of the gear case....any suggestions on repairs/?? Can this be cut out and welded? Any ideas what would cause this?
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Lower Unit Corrosion

A photo would be helpful. Is "quarter-sized" corrosion clear through the case, a hole? If it's not through the case, you could clean/wire brush it, patch it with JB Weld, file, sand, paint. Is it a saltwater motor? :)
 

fredbrillo

Recruit
Joined
Mar 26, 2011
Messages
4
Re: Lower Unit Corrosion

Yep a saltwater engine....South Florida.....Ive already put some JB Weld on it...but didnt clean it well enough the first time and its bubbling under the JB Weld...Im off to Harbor Freight to get some Nylon and/or Brass brushes to see if I can get it clean before I reapply the JB Weld again..

I suspect that the older Pro50 engines werent saltwater protected...as they were designed for Bass Boats...and were extra light weight.
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Lower Unit Corrosion

After you wire brush it, clean it with something like Acetone to remove all oil/grease so JB Weld will hold good. Maybe use a spray Primer before you paint. I use some spray paint from Advance Auto called something like "Automotive Grey/Blue Metallic" that's a darn good match for the Yamaha paint color. Take your motor shroud with you to match the color. Are your Zinc Sacrificial anodes good and clean?...maybe wire brush/sand them so they help with corrosion.:)
 
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