Yanmar 3YM20/SD20 saildrive - sea cock question

[VicS]

I guess that the Yanmar original is bronze but I would use some grease I was fitting a new valve. I'm not sure whether that's classed as direct contact or not but unless one can find an aluminium or "plastic" valve it's probably the best one can do I suppose.

Richard

Why bronze ?

I think if I could not insulate the valve ( grease wont do it) Id opt for stainless steel on the basis that it will lose its passivation in contact with aluminum and the potential difference between it and the aluminium will then be less than that of bronze or brass.

 

[blxm]

Looking at other threads and the earlier post on this thread SS seems to be the norm for the conversion. Thanks VicS.
The ball valve conversion will make life simpler as access to the gate valve was awkward.

 

[RichardS]

Why bronze ?

I think if I could not insulate the valve ( grease wont do it) Id opt for stainless steel on the basis that it will lose its passivation in contact with aluminum and the potential difference between it and the aluminium will then be less than that of bronze or brass.

Because it looks like bronze or it could be brass.

But now you seem to have opted for stainless steel which has left me confused. However, that would also be my choice as a replacement ball valve with a good dollop of ally grease.

Richard