I am working on my cousins 91' 85hp and on the lower unit there are three flat headed screws, one says "wash" one says "Fill" and the other is just the drian plug for the gear lube. I am mostly unsure of what the "wash" hole is for, any help is apprecaited. I loosened the screw and there was a little water in there but thats about it. I know of the other two holes functions, I changed the gear lube in them.