Yamaha - Carburetor Assembly 2 Fuel System Component 6J8-14302-02-00. Overview. When a motor starts running uneven or bogging down, the carb is usually where I look first. I've swapped assemblies like this on plenty of Yamahas, and it's one of the quickest ways to bring an engine back to life. Once fuel delivery is steady again, everything smooths out-idle, throttle, all of it. It's a solid fix when the old unit just isn't keeping up anymore.. Key Features. Balanced Fuel Delivery - Provides cons