My boat came with a foot pump to pull water out the bottom of the icebox. It failed within two weeks of my owning the boat, which resulted in about 8 inches of foul-smelling, murky harbor water filling the bottom of the fridge. Yuck!

I thought I'd share my learnings / tips 'n' tricks for fixing / removing / replacing the pump, which on my 2003 Mk II was a Galley Gusher Mk III by Whale Pumps (UK).
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[*]Access to the pump is from beneath the stove. You have to remove whatever is underneath the stove, and this can be the tricky part. On my boat, the PO had installed one of the exchangers for the hydronic heating system here (I think out of the factory there's storage of some sort?). Once pulled away, however, getting at the pump is pretty easy.
[*]There's a pretty comprehensive repair kit available for this pump, with all new rubber and plastic components. You want Whale Water Systems AK0553. Best price I found was on Amazon: [url]http://www.amazon.com/gp/product/B0064N0SV8/ref=oh_details_o00_s00_i00[/... (~$26 after shipping and no sales tax) but you may find a better price elsewhere (West Marine wanted $32 plus shipping and tax; none of my local stores stocked it).
[*] The Whale Water Systems web site has a great schematic of the pump, which was extremely helpful for the rebuild: [url]http://www.whalepumps.com/marine/siteFiles/resources/docs/resource-libra...
[*] If you have to replace the pump, the one installed on our Catalinas (at least my 2003 mk II) is the "right handed" version. The cheapest place I found it is from a mail-order supply house in Georgia called "Liquid Waste Industries." When I ordered it from them, just a month ago, it was $64, but they've since upped the price to $80; it was about $10 to ship UPS ground. Not sure if it will come back down, but other places (e.g., boatstore.com, Defender) all have it for around $100 after tax and shipping. YMMV but you could save 10% ordering through LWI. Note that they require you to call in your credit card number, no online payment processing, so it is a bit of a pain.
[*] If you do buy a new pump, note that the new ones don't come with backing nuts for the screws. However, the plastic is soft enough that with a decent ratchet/screwdriver and some elbow grease you can basically tap into the plastic with the bolts that held the old pump in place. I pre-screwed about 1/4 of an inch before I installed the pump, which made the process much easier.
[*] Finally, a word of caution: after an hour or two disassembling, cleaning, and re-building the pump, I managed to crack the housing when I was reassembling it! The problem is getting the in/out assemblies together with the rest of the housing, as the o-rings make it a really tight fit. To avoid the mistake I made, assemble the side of the pump with the spring [B]first[/B], making sure to tighten the screws evenly (1-2 turns per screw at a time) as you put the casing together. Then put the in/out assemblies in and do the same (1-2 turns per screw at a time, moving around the pump). You can use the force of the screws to push the in/out assemblies into place. If you take one of these apart, or look at the schematic, it should be clear what I'm talking about (PM me for more info / help if you need it).
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Hope this is helpful! It was a relatively easy and simple repair but the first one I did on my boat, and I thought others could benefit from the experience. I'm happy to answer any questions if anyone else has to do this. Good luck!