99101-ZH7-0780 Jet, Main (#78) - Overview. The 99101-ZH7-0780 Jet, Main (#78) is a precision-engineered main jet designed for Honda marine engine systems. It controls the flow of fuel to the carburetor during high-speed engine operations, ensuring reliable and efficient combustion. Manufactured to meet exact factory dimensions and tolerances, it guarantees seamless integration with existing parts, maintaining optimal performance and durability.. Key Features. Controls fuel delivery in Honda carb