Sorry if this repeats, I posted it once, but Yahoo seems to have sent it into the cyber ether...
I am a little ahead of you on this project.
If you look under the drive pulley, you'll find a cotter pin through the stainless steel drive tube. Pull this pin, and the drive tube and pulley will lift out of the lower Delrin bearing in the stanchion base. Pull it to one side, and then it will drop down out of the upper bearing at the top of the stanchion. Now you have it in hand.
I have attached a photo of the drive tube with the pulleys removed...
On the pulleys as installed on my boat, the holes in both the upper and lower flanges were threaded. On the new pulleys we just received from Amel, only the lower holes are threaded. It will be a lot easier for you if yours are like the new ones! The new ones have a keyway cut in them which is not used in the assembly on my older boat.
The following assumes that the existing pulley flanges are not worth saving. Mine certainly were not!
I used a cutting wheel in my angle grinder to cut the bolts between the two halves of the pulley. Be careful not to cut into the drive tube! That released the lower pulley flange. If the holes for the machine screws in the upper flange are NOT tapped, you should now have an easy time of it, some tapping and prying and the upper flange should come off.
If the upper holes are also threaded, you are only half way there. I could not figure out a way to cut the screws without risking damage to the drive tube, so I needed to unscrew them.
Get a torch. MAPP gas would be the best, propane will work, but a bit slower. Not a little pencil torch, a big one. Everything is metal, so you can't hut it.
Heat the aluminum pulley flange. Heat it HOT. When you think it is hot enough, heat it more. You likely can't get it to glow red, but if you could that would be great! Now, plunge it into a bucket of cold water. Be careful of hot steam and splashing water. Try to remove screws. Repeat. It WILL eventually work. Might take three or four heating/cooling cycles.
Be sure your screwdriver fits the slot in the machine screws exactly. If you mangle the slot, you will have made this harder. This is one case where if the head twists off, it actually counts as a win!
Alternatively, you can drill/grind the heads off the machine screws. When the heads are thin enough, you can use a center punch to drive them down with the screws still stuck in the pulley flange. This is tough to do without marring the stainless drive flange.
When reassembling, be sure to use lots of Tef-Gel or Lanocote, or whatever flavor of corrosion inhibiting anti-sieze you swear by. Be sure to coat every place two metal parts touch. If you do, it will come apart--without drama--in 10 years.
Aren't boats FUN???
Annapolis, MD, USA