CARBURETOR FLOAT 80591M

Function and technical context

The carburetor float is an essential component of the fuel delivery system on Mercury and Yamaha sterndrive engines. Its main function is to automatically regulate the petrol level in the float chamber of the carburetor, ensuring that the engine receives the exact amount of fuel necessary for optimal combustion. This mechanism works through a floating lever system that opens and closes the fuel inlet needle as the level of the internal tank varies. A defective float causes imbalances in the air-fuel mixture, resulting in difficult starts, irregular engine operation, excessive petrol consumption and loss of power when cruising.

When to replace this part?

Carburetor floats can deteriorate due to internal corrosion, microcracks that allow fuel to enter, or hardening of the material after years of exposure to petrol with additives. Symptoms of failure include visible petrol leaks from the carburetor drain holes, repeated failed starts, unstable idle speed, and abnormal fuel buildup in the crankcase. It is recommended to check and clean the carburetor annually before the boating season, and replace the float preventively if it shows signs of corrosion, deformation or loss of tightness. Changing the float before it causes failure avoids costly emergency repairs at sea and ensures reliable engine operation throughout the sailing campaign.

Engine Compatibility

Compatible Mercury Mariner Engines

Equivalent manufacturer part numbers