Merc 25 hp 1994 lower unit repair possible?

[mikkop]

Hi,
When i dropped the lower unit of my 25 hp mercury outboard (1994) to replace the impeller I noticed that the part underneeth the plate of the waterpump was in very bad shape. There rubber was old, hard en broken and dificult to remove. Once remove the rubber I saw the golden part (I think the basepump) was in very bad shape. Is it possible to replace this part and how do I get this part out of the shaft.

Thanks,
Michael