Hi Felipe,
Yes, without all 3 pieces: name, date, and freguesia, the archive isn't helpful at all. They have been that way for years and years.
However, you think they are from either the city of Ponta Delgada proper or somewhere in the council of Ponta Delgada. That's about 45,000 people to search! The Azores have their passaportes leaving the country, but the port of Ponta Delgada has gaps and 1891 is one of the gaps (they are missing a number of years in the early 1890s).
You're going to have to make a list of all the freguesia in Ponta Delgada and go through them one by one. If your Manuel was the oldest, it may be easier to search for his parents' marriage in 1886 or before. I'd start with the 3 main churches in Ponta Delgada: São Sebastião (the Matriz), São José, and São Pedro. Then I'd start hunting through 20 churches in the other freguesia in the council of Ponta Delgada.
Good luck,
Cheri Mello
Listowner, Azores-Gen
Researching: São Miguel island: Vila Franca, Ponta Garca, Ribeira Quente, Ribeira das Tainhas, Achada