Jigflinger is right ,serial number reveals the year and other info.Changing the impeller is not hard.Suggest buying the "kit" as that gives you the impeller,seals,and housing--everything you need .The guys on CDC can nurse you through doing the job if you want.....Youtube videos help also..There are parts supply houses that can be helpful .Many on the web.an example is one I have used a few times is Marine Parts Plus and there are lots more...