What should you check on needle valves?

When checking needle valves, it is crucial to look for burns, grooves, or bent needle tips because these physical conditions can significantly affect the valve's performance. Needle valves are designed to control the flow of fuel or air in small engines, and any damage to the needle itself can lead to improper sealing or flow regulation. If the needle is burned or has grooves, it may not seat correctly, leading to leaks or inefficient operation. A bent needle tip could prevent the valve from closing fully, which again may cause operational issues like flooding or poor engine performance.

While other factors such as lubrication, color discoloration, and carbon buildup can be important in the broader context of maintaining small engines, they are less directly related to the immediate functionality of needle valves compared to the physical integrity of the needle itself. Ensuring that the needle tips are in good condition is essential for reliable engine performance and proper fuel or air management.