A spark plug seals the combustion chamber. It conducts a spark that is generated in the ignition coil into the combustion chamber and provides a gap for that spark to jump across. Finally, it conducts the heat it picks up in the combustion process to the cylinder head and into the cooling system. Since 1936, NGK has built itself to be the world's leading spark plug manufacturer. NGK's spark plugs have a triple-gasket sealing process which helps them to withstand the roughest ride. A solid copper core increases spark and heat transfer and the longer insulating nose prevents fouling. The double dipped zinc-chromate shells resists corrosion and rusting.
Over time jet ski spark plugs can deteriorate from producing the spark. When this happens, it changes the spark plug gap causing irregular spark and missing. You don't have to wait to change your plugs. When you do change them, however, wait for the engine to be cold. Do notchange them when the engine is hot or warm because it could cause you to cross thread it by putting a cold spark plug in an heated up expanded hole.
2003 STX 12F
2004 STX 12F
2004 STX 15F
2004 STX-15F
2005 STX-12F
2005 STX-15F
2006 STX-12F
2006 STX-15F
2007 STX-12F
2007 STX-15F
2007 Ultra LX
2008 STX-15F
2008 Ultra LX
2009 STX
2009 STX-15F
2009 Ultra LX
2010 STX-15F
2010 Ultra LX
2011 STX-15F
2011 Ultra LX
2012 STX-15F
2012 Ultra LX
2013 STX-15F
2013 Ultra LX
2014 STX-15F
2014 Ultra LX
