Optimized carburetor kit designed for Stihl FS-series trimmers and compatible small engines. It helps the engine burn fuel more efficiently by tuning the fuel air mixture, reducing waste and emissions, and improving overall performance. Key benefits - Easier starting, smoother idle, and steadier RPM with improved throttle response and acceleration. - Durable construction using corrosion resistant materials built to withstand tough outdoor use and deliver reliable service for years. - Reliable fuel flow control that minimizes fuel starvation and leaks to support stable operation. Specifications and compatibility - Fits Stihl FS120, FS200, FS250, FS300, FS350, and FR450 string trimmers. Confirm compatibility with your model before purchase. - Includes carburetor unit, primer bulb, and essential fuel line components to complete a rebuild. Use scenarios - Restoring an older FS series trimmer that struggles to start or stalls under load. - Maintaining a lawn mower or string trimmer for consistent idle and throttle response after seasonal storage. - DIY maintenance to improve fuel efficiency and reduce emissions during regular lawn care. Notes - Installation requires basic mechanical knowledge and the correct tools.