W25SBK Weed Eater Trimmer - Instructions

Remove the 4 screws holding the rear motor casing. Then you can take the easy route and drill through the front motor housing with a 3/8 to 1/2 bit in order to access the front muffler screw. If you want to work harder you must remove the motor from the shaft, remove the clutch assembly (this requires a long 15t torx bit, removing the spark plug to stuff the piston with rope or rag to seize up the piston, and then removing the front motor casing to access the front muffler screw). Once you access both muffler screws remove them with the t20 torx driver. Install the new muffler with the small gasket inside the housing, and the larger gasket/heat shield between the muffler and the motor.