I am going to winterize my boat myself.  Do I change the oil now, or in the spring?  Do I blow out the water after draing, I don't want to spend 7 gs on a new block.  I looked at the maintenance page, but it said something about looking at the owners manual.  I don't have one. Is there anything else I can do for precaoutionary wories.   Thanks Bart  (boat will be stored outdoors)