Abstract: A fuel system is provided for a combustion-powered tool having a self-contained internal combustion power source with a combustion chamber, and constructed and arranged for driving a drive blade to impact a fastener and drive it into a workpiece. The tool includes a housing having a main chamber enclosing the power source and having a first end adjacent a nosepiece wherein the fasteners are positioned prior to driving, and a second end opposite the first end and adjacent the combustion chamber. A fuel cell chamber is in communication with the main chamber and has a first chamber end corresponding to the first end of the main chamber and a second chamber end corresponding to the second end of the main chamber.