Need to convert a 2002 merc 5.0 carb engine which was coupled to a Bravo drive to fit with an Alpha drive.
What parts have to be replaced or taken out?

Iknow the seawater pump has to be removed. And you might have to change out the fuel pump also.

The entire transom assembly, inside and out, has to be replaced. The Alpha will not bolt up to a Bravo assembly. You'll aso need to set up the Alpha shift interupter which briefly kills the ignition as the Alpha changes gears. You may need new shift cables too. The cooling lines are different and will require modification.
With the Alpha you don't need the engine mounted water pump, it's built into the drive.

Question: Why would you change from the Bravo to Alpha???? The Bravo is much stronger than the Alpha.
There are more people switching up from Alpha to Bravo than the reverse.

Perhaps he bought the engine to install in an Alpha boat?
Also fwiw as far as engines go, as long as the alignment is good and the proper coupler is installed, they don't know what drive they're bolted to.
So depending on exactly what the situation is, you need to swap the control pieces from the old motor, possibly the coupler/bellhousing, properly rig up the raw water cooling.

[QUOTE=handfulz28;2240971]Perhaps he bought the engine to install in an Alpha boat?
QUOTE]

Yes, engine came out Bravo drive boat and goes now in Alpha drive boat
Thx for all replys

One thing to watch is the bravo coupler may interfere with the water inlet hose coming off the drive. It did on mine (Merc 383 to Alpha gen 1)

I needed to add a thru- transom pickup and seastrainer for the bravo pump. I capped the alpha pump off

I had to cut the nipple down and use a 5/8" hose, ditching the adaptor (the 5/8 hose clamped directly to the nipple) I have to bend the hose immediately off the nipple. It is still close, abouut 1/4 from interfering.

You could avoid all this mess and trouble by using an alpha coupler. I would have had I known before hand.