I just replaced my bilge pump, so I'll describe my experience in case it helps others.
My boat is a 2004 H230, but from reading here it sounds like most of the Four Winns are very similar in this regard.
Facing aft and looking straight down the front of the engine compartment, I have a well where there is always a little water. Just aft of that is a mostly white rectangular box with 2 gray wires. That's the float switch.
In this picture, you can see the float switch under the nose of the engine. It has blue writing on the top.
Just aft of the float switch is a small cylinder (a little smaller than a 12-oz drink can) with a red top, white middle, and blue bottom. It has a brown and a black wire. That's the pump.
The base of the pump is screwed into the boat, and the main body of the pump is clipped into place on that, so the trick is to squeeze the clips and pull the pump out without damaging the base. Once it's free of the base, you can work it over to the starboard side of the engine where you can get at the hose clamp holding the drain line in place. Once it's out, you can take the pump to the marine store and probably find one that uses the same base, making the job much easier, since unscrewing the base under the engine would be tough! I was able to find the identical pump at West Marine for about $30.
My float switch looked a little dirty, so I pulled it out. A little stretching with a long philips was needed, but it's only 2 small screws. There was enough crud in there that I'm glad I pulled it out. As an aside, it looks like any dirt that ends up in the ski locker gets washed back to the bilge area, and can get to the switch and pump, so it's worth NOT putting dirty stuff down there.
The wiring was tie-wrapped into a bundle and fastened to the boat with 2 screws just below the starboard corner of the engine. All 4 wires from the float switch and pump came together into one 4-pin connector that was easy to disconnect (squeeze the sides and pull apart). However, I didn't have the right pin-extractor or replacement pins to swap in the new pump, which came with just the wire (no connectors). So, I spliced the new wires to the old with a soldered joint.
The toughest part of reassembly for me was tie-wrapping the wires back together because it really needed two hands and I could only get one down there. Be careful to not overtighten the hose clamp or overstress the plastic nipple it goes over--my old pump was cracked there, and while researching the job on this board I read other stories of cracked nipples.
If you disconnect the wiring first (at the 4-pin connector), you probably can get by without disconnecting the battery, but it is never a bad idea to pull the cables off of one side of the battery when working in the engine bay since there are a few "always hot" wires in there and if you slip and short something out it could turn a small job into a big one real fast.
Take your time being careful to not drop parts. If they roll back under the engine, you'd better hope that Helen Parr (aka Elastagirl) lives down the street...
When you're done, you can test the helm switch and hear the pump humm, and then "just add water" to test the float switch (drain plug in if you're out of the water). It takes more water than you might expect to activate the float switch. Using actual water is important so you can make sure the hose is well attached and not leaking. If all is well, you'll see:
Good luck!
Rich
Does an 1100GPH need a bigger hose/hole? I wouldn't want to burn out the pump from too much back pressure. Clearly a second pump would need an additional hole and hose.
