2004 Skidoo ZX Series Service Manual, Page 373Get this manual
Section 07 ENGINES MANAGEMENT (4-TEC) Subsection 02 (COMPONENT INSPECTION AND ADJUSTMENT)
Disconnect the wiring harness from the ignition coilRemove the ignition coilFirst unscrew the spark plug one turnClean the spark plug and cylinder head with pressurize air then completely unscrew
Spark Plug Installation
Prior to installation make sure that contact surfaces of the cylinder head and spark plug are free of grime Using wire feeler gauge, set electrode gap according to the following chart Apply anti-seize lubricant over the spark plug threads to prevent possible seizure Hand screw spark plug into cylinder headThen, tighten the spark plug clockwise an additional 14 turn with proper socket