get rid of them soon
If you do a search in the archives here for seacocks or gate valves, you should come across a wealth of discussion on this topic. I won't re-invent the wheel here, but I recommend, on the STRONGEST possible terms, that you replace any gate valve type seacock with a modern ball-type seacock NOW. It's hard work, but it will save your ship. In short, gate valves tend to fail from the inside out. There is a very very high probability that original gate valves on a 1985 boat are either already shot or near death. I am not being over-dramatic on this topic.