Yamaha - Carburetor Case Fan Set Cooling Component 99999-04316-00. Overview. When you're running your Yamaha hard, especially in hot conditions, heat buildup around the carb area can start affecting performance more than people realize. I've seen engines that run fine at idle but struggle once things heat up under load. The Yamaha Carburetor Case Fan Set 99999-04316-00 helps keep airflow moving where it matters, so the carburetor stays cooler and more consistent. It's one of those upgrades that