Thank you for your feedback. We are glad to hear the trimmer has the power you were expecting, but we understand how frustrating it can be when the line does not advance properly during use. A few things may help improve auto-feed and bump performance: first, confirm the spool is installed correctly and seated fully in the head, with the line routed cleanly through the eyelets. Check that the line is the correct diameter (.080" is typically recommended for this model) and not tangled, crossed, or wound too tightly, as this can prevent proper feeding. It can also help to remove the spool and rewind it evenly with light tension, ensuring the line follows the directional arrows on the spool. During operation, make sure to bump the head on a firm surface while running at full speed, as insufficient RPM can prevent the mechanism from advancing the line. Additionally, inspect the bump knob and spring for wear or debris that could restrict movement. For helpful visual references, we recommend checking our Greenworks YouTube channel for instructional videos and additional tips that may assist with trimmer head maintenance and line replacement. If the issue continues after these checks, our support team would be happy to assist further and help identify any potential defects or compatibility concerns. They can be reached either using the online chat function, on Greenworks Tools page, or by calling 1-888-909-6757. We appreciate your patience and your feedback.