An even pull with two fingers is sufficient. Compared with conventional starters, the STIHL ErgoStart not only needs less effort but also allows the starter rope to be pulled two-thirds slower. The even pull on the starter rope tensions the spring against the compression pressure. Stresses caused by jerky movements are avoided. The spring automatically releases the stored energy to the crankshaft, starts it moving and ensures that the engine will start reliably.
A spring housing with the spring and two drive lugs is fitted between the rope rotor and the crankshaft. The force used to pull the starter rope tensions the spring against the opposing force created by the piston during compression. If the energy of the pretensioned spring is greater than the opposing force created by the piston during compression, the crankshaft starts to turn and the engine fires.