Sacrificial Anodes

[MolarBoater]

Noticed corrosion on my lower unit, 2002 Suzuki DF140. Sanded and painted with black engine paint(600 degree). Anodes are looking pretty rough too. Should these be replaced every year if boat has been in salt water or should you wait for the tell tale sign of corrosion? I am going to order "RustBullit" paint for some ironwork at the house, may try it later.
Happy to have the boat back, it's a great place to store gas for the generator in hurricane season!
Emery

 

[Cincinnati]

At $4 per anode, I'd replace them. There should be a third 10" or so anode on the stern bracket that may run upwards of $30. If they appear to still be close to the original size, you can sand them down - I'd just put new ones on.

 

[Codfish]

MBoater, Remember that a pitted anode just tells you it is working like it's suppose to. The more pitted, the more surface area, the better it works. I would not necessarily replace the anode until it is loosing defined shape. (Manual defines that as 2/3 gone.) A new anode does not guarantee less corrosion. Keeping the bare areas of shaft housing that corrode painted is your best bet. Corrosion on the lower unit can be an indicator of trouble on the horizon. Don't neglect the signs of corrosion. If your lower unit seal fails from prolonged submersion in salt water then you have major issues and a potentially large repair bill. I would suggest checking your gear box oil just to be sure you do not have a bad seal. This is a good idea every year if you leave the motor in the water for extended periods.

I know my DF140 raises out of the water at full up. Only the transom bracket anode is in the water then. Hope this helps.

codfish

 

[MolarBoater]

Thanks, the anodes look nice and corroded but still mostly all there, I just don't want a sacrificial lower unit before I know better. I just noticed the corrosion on the edge of the housing around where the prop sets into and lightly back down into the housing. Had to get a small wire brush down in there and rinsed it out with alcohol prior to painting. Might replace them in the spring for peace of mind, sounds pretty inexpensive.