Why does Huck's conscience bother him throughtout the novel? What is so troubling to Huck, and how does he finally overcome it?

Huck really likes Jim the "escaped" slave. Although buck is a product of the South, he seems to develop his own moral compass. He struggles with the expectation that he turn Jim in but his own moral code tells him it is wrong. Huck finally does the right thing by springing Jim out of jail.