Mercury - Composite Carburetor Float Fuel System Component Composite Material 9594. Overview. If you've run a classic Mercury two-stroke for any length of time, you know how much personality these engines have-and how quickly they'll tell you when something's off in the carburetor. A sticking float, a worn pivot, or a fuel level that just won't stay where it should can turn a smooth day on the water into constant fiddling. That's why a dependable replacement like the Quicksilver 9594 Composite F