Backpack Brushcutters · part-number series 4146
FR 3900
8 exploded views, 181 part numbers.
Factory tuning settings
| Idle speed | 2,800 rpm |
| Max speed | 11,500 rpm |
| LA screw (idle stop) | 2 (LD-SCHRAUBE) turns |
| Confidence | sourced |
Screw figures are turns open from lightly seated. Set the final mixture by ear and tachometer against the machine in front of you — running a two-stroke lean to hit a published number is how pistons get scored.
Parts are not interchangeable across series — check yours before ordering.