i just got this 2725 and the line advance bump feed doesn't seem to work at all, what am i doing wrong

Diagnosis

The failure of the bump feed mechanism on the Milwaukee M18 FUEL 2725-20 is almost always a result of "spool binding" or improper line seating within the Speed-Load head. Because this head relies on a precise centrifugal release, any friction caused by overlapping line or an incorrect line diameter prevents the internal spring and clutch from releasing the spool when you strike the bump knob against the ground. If the line is wound too loosely, it will "nest" and jam; if it is wound too tightly or with the wrong gauge, the spool cannot rotate freely enough to advance. To confirm the root cause, remove the battery and attempt to pull the trimmer line by hand. If the line does not budge or feels "stuck" despite the bump knob being depressed, the line has likely jumped its track inside the spool or was not locked into the anchor notches during loading. If the line pulls out easily but does not advance during operation, the centrifugal force isn't triggering the release, usually due to using a line diameter thinner than 0.095", which lacks the necessary friction to grip the spool's drive mechanism.

How to Fix It

To restore the bump feed functionality, you must perform a complete reset of the Speed-Load head. Follow these exact steps:

1. Remove the M18 battery for safety. Remove the bump knob by unscrewing it counter-clockwise from the head assembly.
2. Extract the spool from the housing. Inspect the line currently loaded; ensure you are using 0.095" diameter round or twisted line. If you are using 0.080" or 0.065" line, it will likely slip and fail to advance.
3. Completely unwind the existing line. Cut a fresh piece of 0.095" line exactly 20 feet in length. Any longer and the spool will overfill and jam; any shorter and you will run out of line before the spool completes a full rotation.
4. Locate the anchor notches on the interior hub of the spool. Push one end of the line firmly into the notch until it clicks or seats fully. This is the critical "lock" point that prevents the line from spinning inside the spool.
5. Wind the line clockwise around the spool, keeping the wraps tight and neat. Ensure the line stays within the flanged guides of the spool and does not overlap or cross over itself.
6. Leave approximately 5 inches of line extending from the spool. Slide the spool back into the housing, aligning the notches with the head's internal drive.
7. Thread the line through the eyelets and cut it to length using the integrated blade on the guard. Reinstall the bump knob and tighten it firmly.

If That Didn't Work

• Check for debris buildup inside the head housing. Grass clippings and wet dirt can pack into the spring mechanism of the bump feed. Use compressed air or a stiff brush to clear the cavity around the spool to ensure the bump knob can travel its full distance.
• Inspect the bump knob for wear or cracks. If the plastic knob has deformed or cracked, it may not be applying a centered force to the release pin, meaning the "bump" never actually triggers the spool release. Replace the knob if the center pin is skewed.
• Verify the line material. Some "soft" or "premium" nylon lines stretch under high RPMs. If the line stretches too much, it can lose the tension required to trigger the centrifugal release. Switch to a high-density copolymer line to see if the grip improves.
• Check the spool for warping. If the tool was dropped or the head hit a concrete wall, the spool may be slightly ovalized. A warped spool will bind against the housing walls, preventing rotation regardless of how many times you bump the head.

Heads Up

• Avoid "over-bumping." Striking the head with excessive force can damage the internal spring or crack the housing, leading to a permanent failure of the advance mechanism.
• Never use line thicker than 0.095". Using 0.105" or thicker line will put excessive strain on the M18 motor and can physically jam the Speed-Load mechanism.
• Periodically clean the cutting head with a damp cloth after use. Dried grass paste acts like glue inside the spool housing and is a leading cause of "stuck" bump feeds.
• Ensure the battery is fully seated. Low voltage can occasionally cause the motor to run at a lower RPM, which may not provide enough centrifugal force to release the line in some head configurations.