O.K gentlemen, just bought< well a week ago, a 1987 270 TM in a so so condition, a few gel cote cracks on the liner corners and a very bad electrical work, all works good but not a sign of marine wire and connectors. Anyway, that would be after season project for me.
I do have a question, and I am sure will be more to come

, is about the "valve" that is used for overboard discharge. I want to close it but it will not turn.
Is this a regular valve or is it something more than a valve. Why am I asking? because it does not look like any other overboard discharge valve I've seen.
This is like a small barrel on which on one flat end is a yellow handle and on the other flat end there is a T handle. On the side where the yellow handle is there is also two bolts and a cap which looks like the cap of an inboard engine strainer. The boat is still on the hard so if i have to remove everything i can still do it.
Oh, there is another thru hull with a regular ball valve up in the front starboard side right under the head sink, there is nothing connected to that seacock, is shut, but i don't know the use of it.
Thank you very much in advance.
P.S Any boat manuals on the 270 TM out there that we can download?