There are at least two main reasons why there were more slave revolts in the colonies outside of North America.
First, we can look at the conditions in which the slaves worked to understand this phenomenon. In the Caribbean and South America, slaves were frequently worked much harder than they were worked in North America. It is said that slave owners in the Caribbean felt that it was more economical to work slaves to death and then buy new ones than to treat the slaves in ways that would allow them to live longer. This can be seen in part by the fact that the slave populations in the North American colonies actually grew by natural increase while those in the Caribbean did not. What this factor means is that slaves in the Caribbean had more of a reason to rebel.
Second, the slaves in the Caribbean represented much larger proportions of the population. In North America, there were some colonies where slaves predominated, but the colonial population as a whole was overwhelmingly white. By contrast, white populations were quite low in the Caribbean and South America. This would have given slaves more of a feeling that they could prevail in slave rebellions.