Troubleshooting welding issues is an important skill for welders, and recognizing when it's time to change the liner can help ensure optimal weld quality. In the scenario you mentioned, where the liner had drag and resulted in sooty welds, along with identifying a long arc length, here's some troubleshooting guidance:

Liner Condition: If the liner has drag or excessive wear, it can affect the wire feed and lead to inconsistent or poorquality welds. Drag can occur due to accumulated debris, kinks, or excessive wear inside the liner. If you notice drag or resistance while feeding the wire, it's an indication that the liner needs to be replaced.

Sooty Welds: Sooty or dirtylooking welds can be caused by a variety of factors, including improper shielding gas flow, contaminated base material, or insufficient wire feeding. However, in this case, the drag in the liner could be a contributing factor. A worn or dirty liner can disrupt the smooth feeding of the wire, leading to erratic arc behavior and poor gas coverage, resulting in sooty welds.

Arc Length: A long arc length refers to the distance between the electrode (wire) and the workpiece. An excessively long arc can lead to a weak and unstable arc, increased spatter, and poor weld penetration. To address this issue, it's recommended to decrease the synergic voltage or adjust the welding parameters to achieve a shorter and more controlled arc length.

When troubleshooting welding issues, it's important to consider various factors that can impact weld quality, including equipment condition, settings, and technique. Regular maintenance, such as replacing worn liners, can help maintain consistent wire feeding and improve overall welding performance.

Although complete pictures of the welds would have provided additional context for troubleshooting, addressing the liner drag issue and adjusting the arc length are important steps to improve weld quality.