Can anyone shed some light on the repair or replacement of the seacock for the DD 671 on a 1982 Viking 44'
I'm not the Viking expert but handy with most sea cocks. Without a brand or model description in your comment and not wanting to 20 question drill you, Do you have a couple of pictures and explanation of why it needs replacing?
If it's stuck, in the majority of cases it can be unstuck. If it needs replacement, google Buck Algonquin. If it needs replacement due to a bonding issue that will have to be addressed also. As already mentioned more detail is needed.
I would NEVER recommend buck algoquin. They mate a stainless handle to a bronze seacock and the handle eats the stud on the seacock it's mounted to.....I like Apollo or groco.
+ 1 Buck doesn't compare to Groco metallurgy wise or in their sand castings / 1st choice Groco & Apollo 2nd .