I am also researching an ancesstor from Italy that changed his name to Adams. I learned from a post similar to this one that persons with the name, Adamo, usually changed their names to Adams upon arriving in the USA. You might try locating him with that surname and then go forward from there. I wish you the best of luck in your search.
I managed to find my great grandfather Frank Raphael "Raffaela" Adams "Adamo" after he arrived here in the states(census 1910), but I am having trouble finding his gravesite when he died in 1912 in Lafayette Co., Arkansas.