Bombardier SeaDoo 1992 factory shop manual, Page 167Get this manual
Section ELECTRICAL Sub-section 07 (SPARK PLUGS)
DISASSEMBLY
First unscrew the spark plug one turnClean the spark plug and cylmder head with pressurize air then completely unscrew
FOULING
Fouling of the spark plug is indicated by irregullar running of the engine, decreased engine speed due to misfiring, reduced performance, and increased fuel consumptionThis is due to loss of compressionOther possible causes areprolonged idling, or running on too rich mixture due to faulty carburetor adjustment or incorrect fuel andor fuel mixingThe plulg face of fouled spark plug has either dry coating of soot or an oily, glossy coating given by an excess either of oil or of oil with sootSuch coatings form conductive connection between the center electrode and ground
HEAT RANlGE
The proper operating temperature or heat range of the spark plugs is determined by the spark plug ability to dissipate the heat generated by combustionThe longer the heat path between the electrode tip to the plug shell, the hotter the spark plug operating temperature will beand inversely, the shorter the heat path, the colder the operating temperature will be