2005 Ski-Doo Tundra, Skandic, Expedition Shop Manual, Page 446Get this manual
Section 08 ELECTRICAL Subsection 02 (SPARK PLUGS)
DISASSEMBLY
First unscrew the spark plug turnClean the spark plug and cylinder head with pressurized air, then completely unscrew
WARNING
Whenever using compressed air, always wear protective eye wear
A too hot plug will result in overheating and preignition, etcA too cold plug will result in fouling (shorting the spark plug) or may create carbon build up which can heat up red-hot and cause pre-ignition or detonation
FOULING
Fouling of the spark plug is indicated by irregular running of the engine, decreased engine speed due to misfiring, reduced performance, and increased fuel consumptionThis is due to loss of compressionOther possible causes are: prolonged idling, or running on too rich mixture due to faulty carburetor adjustment or incorrect fuel andor fuel mixingThe plug 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