A fuel delivery system which includes a fuel cell (60) with an outer shell (68) having a closed lower end and an open upper end (72), a closure (70) crimped over the upper end (72) and defining an opening for accommodating a reciprocating valve stem (64), a fuel cell adapter (80) frictionally engaging the closure (70) and including a flange (90) configured for suspending the fuel cell (60) in a tool fuel cell chamber. The adapter (80) includes a collar (96) configured for receiving the valve stem (64) and being suspended for restricted vertical movement relative to the flange (90). A stem receiver block (100) is connectable to a cylinder head frame and includes a stem engagement portion (106) configured for directly and sealingly engaging an end of the valve stem (64), the stem engagement portion (106) being in fluid communication with an internal receiver passage (110) constructed and arranged for delivering fuel to a combustion chamber.