Like many Enlightenment thinkers, Franklin believed that knowledge ought to be useful, and if possible, profitable. Many of his more famous ideas were thus aimed at reforming some aspect of society in such a way as to make it more efficient or effective. His efforts in science, which yielded important findings about electricity, for example, he put to work in creating the lightning rod, a major advance during a period when mostly wooden cities were periodically gutted by fires started by lightning. So he was in this sense very much of that strain of the Enlightenment eschewed abstract metaphysical reasoning for no concrete purpose.
Franklin also held a worldview heavily informed by Enlightenment concepts of reason. After a controversial pamphlet he wrote and published in the 1730s, he generally avoided public comment on religion. But his claims in a newspaper article written in his youth that "a virtuous Heretick shall be saved before a wicked Christian" seem to encapsulate his views on the subject. As one biographer puts it, his views on religion were basically utilitarian:
His respect for the various religions in eighteenth century America came to depend solely on their contributions to virtue or morality.
Franklin's views on government, which emphasized balance and limitations on the sovereign power, were also highly attuned to the Enlightenment thought of such luminaries as Montesquieu and especially Voltaire.
Source: Gordon Wood, The Americanization of Benjamin Franklin (New York: Penguin, 2004) 29-30.