2008 Arctic Cat 366 ATV Service Manual, Page 33Get this manual
Problem: Engine runs poorly at high speed Condition 12345678910High RPM "cut out" against RPM limiter Valve springs weak Valve timing out of adjustment Camsrocker armstappets worn Spark plug gap too narrow Ignition coil defective Float level too low Air cleaner element obstructed Fuel hose obstructed Fuel pump defective
12345678910Shift into higher geardecrease speed Replace springs Adjust timing Replace camsarmstappets Adjust gap Replace ignition oil Adjust float height Clean element Clean or replace hose Replace fuel pump
Problem: Exhaust smoke dirty or heavy Condition
123456Oil (in the engine) overfilledcontaminated Piston ringscylinder worn Valve guides worn Cylinder wall scoredscuffed Valve stems worn Stem seals defective
123456Drain excess oilreplace oil Replaceservice ringscylinder Replace cylinder head Replaceservice cylinder Replace valves Replace seals