To remove door there are adjustable rollers top and bottom. The adjustment screws are on the LH & RH edges top and bottom. They might be frozen so go slow. Back them off and lift roller out of track with a screwdriver.
Bill Arnold 1988 33 FBC Merc 454 'Retriever' SOLD
37 DUFFY. Extended House 3126 Cat.
One of your best friends on your boat will be Corrosion X. I don't know what the newer B33s have, but I was able to pick up new roller assemblies at Home Depot. They were close enough that with a little judicious grinding they fit right in. Al