Car Honda GX120 carburetor fired when accelerating

Sometimes the engine can work normally at idle and medium speeds, but at the moment of sudden acceleration, the carburettor fires and fires.
 

Honda GX120 carburetor The cause of this failure is mainly due to the lean mixture. The mixture is too lean, making the combustible mixture burn slowly, so that the combustion process continues until the intake air starts, the intake valve opens, and the mixture in the cylinder is still burning. Due to the high pressure in the cylinder, it is burning. The combustible gas mixture rushed into the carburetor, ignited the combustible gas mixture in the carburetor throat, and the ignited combustible gas mixture slammed into the carburetor due to rapid expansion, making an explosion sound, and sometimes flaming out.

   The mixture becomes leaner when accelerating, which is mainly caused by the failure of the carburetor accelerating device..The specific reason is: the acceleration pump piston is worn, damaged or too tight. Acceleration pump inlet / outlet valve is not sealed or blocked by dirt, and the acceleration nozzle is blocked.