An internal combustion engine includes an engine block including a cylinder, a piston positioned within the cylinder and configured to reciprocate within the cylinder, a crankshaft driven by the piston, a fuel system for supplying an air-fuel mixture to the cylinder, a starter motor configured to initiate rotation of the crankshaft to start the engine, a cover having a vent opening, a blower housing located between the cover and the engine block for directing cooling air toward the engine block, wherein the blower housing comprises a receptacle electrically coupled to the starter motor, a fan configured to draw the cooling air into the blower housing through the vent opening in the cover to cool the engine block, and a rechargeable battery pack removably attached to the receptacle, wherein the rechargeable battery pack is configured to power the starter motor to start the engine.