The STIHL 4-MIX engine is the first four stroke engine which works on a mixture of petrol and oil. It combines the advantages of four-stroke and two-stroke engines in one. With higher torque and up to 80% less emissions and a deeper more pleasant sound. Combined with a well balanced, loop handle, as a light brushcutter, it makes the FS 100 R a leader in its class. Fitted standard with AutoCut cutting head.
| Displacement | 31.4 cm3 |
| Power output | 1.05/1.4 kW/bhp |
| Weight | 5.5 kg |
| Cutting blade | AutoCut |
| Fuel capacity | 0.53 l |
| Vibration levels left/right | 6.2/6.2 m/s2 |
| Overall length | 1.8 m |
| Sound pressure level | 89.0 dB(A) |
| Sound power level | 100.0 dB(A) |