2008 Suzuki LT-A400/F, LT-F400/F ATV Service Manual, Page 192Get this manual
1H-2 Ignition System: Condition Spark plug quickly becomes fouled with oil or carbon Possible cause Worn piston ringWorn pistonWorn cylinderExcessive valve-stem to valve-stem to valve-guide clearanceWorn valve stem oil sealsIncorrect spark plug (Hot type)Overheated engineLoose spark plugExcessively lean airfuel mixtureCorrectionReference Item ReplaceReplaceRebore or replaceReplaceReplaceChange to cold type spark plugTune-upTightenAdjust carburetor Spark plug electrodes overheat or burn
No Spark or Poor Spark
Troubleshooting NOTE
B827H21804002
Check that the transfer is in neutral and the engine stop switch is in the "RUN" positionCheck that the fuse is not blown and the battery is fully-charged before diagnosingStep Action Check the ignition system couplers for poor connections2 Yes Go to step 2No Poor connection of couplers Faulty ignition switch Faulty wire harness Broken wire harness or poor connection of related circuit couplersGo to step 5