Not been one of my better weekends.... When I bought the boat, the clamp anode had dissappeared, and the trim tab anode had half gone. They were duly replaced, but I found out the hard way this weekend just how corrosive the stainless - ally connection that occurs at bolt threads on the bolts holding a water jacket on becomes when the anodes dissappear (lots of warm salt water floatting around there too!)
In short I managed to strip the freshly cut thread in my cylinder head water jacket bolts using nothing more than a helicoil on it's insertion tool!
The corrosion has turned the alloy of the cylinder head very, very soft.
So, the Moral of the story is don't ignore your anodes, especially if the engine stays afloat (as mine used to in a previous life).
Now for the scroungey grovely bit - does anyone have a spare cyl head for a 2 cyl Yam 45/50/55/60 that is slightly more solid than mine isn't and may want to swap it for some brown drinking vouchers? If not there will soon be a flood of spares for this engine appearing in the "for sale" section soon!