Mercury - Weber 4-Barrel Carburetor Repair Kit Carburetion System Precision Marine Components 8M0120196. Overview. Anyone who has spent time with a classic MerCruiser 4.3LX knows how rewarding it is when the engine fires cleanly, settles into a steady idle, and responds the moment you lean into the throttle. But when a carburetor starts showing its age-maybe a stumble on acceleration, a rough idle, or a bit of hesitation-you feel it right away. That's when a proper rebuild becomes less of a chor