"Everyman's Jet Engine" - Why Valveless Pulsejets? Essentially zero maintenance for continued operation over its useful life Since there are no moving parts, there will be virtually no maintenance throughout the life of a valveless pulsejet. The only notable exceptions are (1) the possibility of replacing the spark plug if damaged; and (2) the removal and replacement of the fuel nozzle for cleaning or repair if it ever becomes fouled with foreign matter or damaged in some way. With minimal care, valveless pulsejets are the most trouble-free jet powerplants ever designed.