Engine hunting, shot

A. The air inlet system: ① if air filter elements clean or not; ② if it is loosened between these spare parts: air filter, carburetor,insulation board and their gasket;

B. The oil level;

C. If the tensioner spring,including the governor spring and idle spring, work or not;

D. If the exhaust vent of silencer be blocked or not;

E. If governor lever, throttle linkage and other related parts be blocked or not;

F. Test again after change a new carburetor.