Isolator Rings and Gaskets can be found between the Carburetor and the Intake Manifold on many 4-Stroke Units. In many cases when suffering from a lack of performance the original isolator ring will be cracked and or the gasket will require replacement. If 19mm Carburetor then you need a 19mm Ring/Gasket Recommendation: It is highly recommended that the isolator ring and gasket be replaced as routine maintenance to ensure proper carburetor idling and operation.
