Yamaha - Idler Gear 1 Engine Geartrain Component 6P2-15512-00-00. Overview. Inside the engine, idler gears don't get much attention, but they play a big role in keeping everything turning the way it should. I've seen motors develop odd noises or timing issues that traced back to wear on a gear like this. When it's in good shape, everything meshes quietly and runs smooth under load. It's one of those parts you don't notice-until something feels off.. Key Features. • Smooth Gear Engagement - Transfers motion cleanly between connected gear components.• OEM Precision Machining - Built to Yamaha specifications for accurate fit and alignment.• High-Load Durability - Designed to handle continuous engine stress and rotation.• Noise Reduction Support - Helps maintain quiet and stable engine operation.. Engine & Boat Compatibility. Designed for Yamaha outboard engines utilizing internal gear-driven systems. Commonly used across a range of Yamaha outboards where precise gear timing and durability