yanmar fresh water pump Identification

[Badsanta]

I have a 3GM30F. I bought an extra fresh water pump for a spare. I bought a rebuild kit for it but it is much to small for the pump. The only identification on the pump is a stamped number 4D-378 What I need to know is what this pump fits. It looks to be the same pump but I cant compare to mine as travel is not possible at this time. The part number for the rebuild kit is K28270-42000 and is supposed to be the right part, So either I have the wrong pump or Kit. I have contacted the Yanmar help but had no response.
any suggestions much appreciated. Alan