Welcome to the Ranch
You have some design problems there. As a general rule,
you should make all fields (except those used as global constants)
private, and provide access to them
via getXXX or setXXX methods as required. Those methods will probably have
public access.
Since you probably don’t intend horsepower ever to change, you would do well to set it up in the constructor, and provide only getXXX methods for it. Make sure only to write constructors which take horsepower as a parameter.