31204-KS5-901 Carbon Brush Spring - Overview. The 31204-KS5-901 Carbon Brush Spring is a critical component within the starter motor of Honda marine engine systems. This spring supports the electrical system by maintaining consistent contact between the carbon brushes and the commutator, ensuring a reliable flow of electrical current essential for smooth starter motor operation. Designed to match precise factory specifications, the spring ensures seamless integration with existing parts, maintai