Quackser Fortune has a Cousin in the Bronx
(1970)

Eccentric young Irishman Quackser Fortune (Gene Wilder) makes his living collecting horse manure from the streets of Dublin and selling it for fertilizer. His family wants him to get a "real" job at the factory where his father works, but he prefers his own work.

He meets Zazel Pierce (Margot Kidder), a young American exchange student at Trinity College. She loves Irish literature and history, things Quackser never knew or cared much about, and she shows him all the places where famous Irish authors (like James Joyce) lived, and all the places where Irish heroes lived and died. Quackser falls in love with her, and is heartbroken whn she returns to America.

Worse yet, almost all the horses and wagons used to make deliveries in Dublin are replaced by automobiles and vans. There will be no more horse manure in the streets, so Quackser's business is doomed. His father insists that Quackser come to work at his factory. Quackser agrees, but is miserable there.

Suddenly, word comes from America that Quackser's distant cousin the Bronx, New York, has died and left him a few thousand dollars. He buys a minibus with the money and starts his own business shuttling tourists around Dublin. Quackser makes an excellent tour guide, since he remembers all the places Zazel had shown him and all the interesting stories she had shared about important Irish authors, artists and statesmen.

Thanks John L!

IMDB