1999-2004 Suzuki King Quad LT-300 300F ATV Factory Service Manual, Page 268Get this manual
SERVICING INFORMATION
Complaint Spark plug quickly becomes fouled with oil or carbon
Symptom and possible causes
1Worn piston ring
ReplaceReplaceRebore or replace Replace Replace Change to cold type spark plugTune-upTighten Adjust carburetorRepair, replace or connect properlyReplace ReplaceRepair or tighten Replace ReplaceAdd distilled water to the upper levelReplace batteryReplace batteryReplace Repair or replace Replace ReplaceRecharge or replaceReplaceRepair or replaceReplaceConnect, tighten or repair
2Worn piston3Worn cylinder4Excessive valve-stem-to-valve-guide clearance5Worn valve stem oil seal
Spark plug electrodes overheat or burn