With false air you suffer from a lean mixture in the cylinders. This is because there is too much air in the mixture, resulting in a malfunctioning engine. The false air is sucked in after the carburettor. False air causes, among other things, a non-idling engine at high revs. In short, the engine runs poorly, your cylinder gets too hot and a jam can occur.
False air can form at the spark plug, between the carburetor and manifold, the manifold and cylinder, and at the left crankshaft seal. Examine carefully and avoid further damage.