One day a mysterious person comes to stay at an inn ran by a boy and his mother. It is obvious that this stranger led a rough sea going life. What was not obvious is that events with his previous associates would eventually lead to adventure and "Treasure Island."
Of course nothing can replace the book "Treasure Island" by Robert Louis Stevenson. However this movie comes closest. I also have a copy of Treasure Island (1934) because that is what I watched as a kid and thought of it as a classic. But Wallace Beery can not come near Charlton Heston as Long John Silver.
What you do not want to waste your time on is Treasure Island (1950) with Bobby Driscoll. This version is chopped up. People are missing. And the story is so sweet that you don't recognize the plot.
If you are or have kids you do not want to miss "Muppets Treasure Island" with Tim Curry (1996).