-my mother-in-law knows i like old outboards and purchased a mark 10 mercury. It was complete but when I took it apart to clean the carb and fuel system and look at the water pump and lower unit I was astounded! Either I'm an idiot or changing the water pump impeller is impossible. Is there any way for this to be done? The gear system was bizarre. What is the value of one of these in non-working condition, if any. I'm thinking that this is a "throw-away" motor. Is there any value in the parts for one of these or does everyone basically cringe at the sight of this monster?