My 2006 150 yamaha with 200 hours on it in the last year and a half has been showing a lot of signs of electrolysis on the sacrificial anode steering skeg. the other main block anode under the outboard looks normal. but why would the steering skeg anode be deteriorating so quickly? What are some tests to be sure I am wired properly? I do have a perko switch and I use it.
I have the same motor, same year, and just replaced that anode recently. I think it’s probably normal - the anode corrodes so your motor doesn’t, and that’s the one that is submerged the most, plus it gets subjected to a lot of turbulent flow that tends to erode any soft spots faster.
I’m sure a real mechanic will chime in but doesn’t seem too unusual to me.
Angler 204 FX
Yamaha 150
I wouldn’t worry about it, that’s why it’s called a sacrificial anode.
As wolfie said, it’s right behind the prop and gets a lot of turbulent water flow which causes cavitation burns, making it erode faster.
If the boat spends much time in marinas around other boats plugged into shore power, that will also increase the corrosion. All it takes is for one of them to have reversed polarity and you get a lot of stray currents flowing through the water.
I’d just replace it and not give it a second thought. Both of those zincs are bolted directly to the motor, so they have to be at the same ground potential.
Capt. Larry Teuton
Cracker Built Custom Boats
Marine Surveying & Repair