Easy start recoils

[Old2stroke]

In these starters the central hub that connnects to the flywheel pawls is driven by a spiral spring from the rope drum. I guess the spring winds up as piston is pulled up to compression and after TDC it accelerates the piston on the downstroke? How does this make an engine easier to start? I know they work so what am I missing?

 

[Franny K]

No shock loads to the arm at max compression. Distribute peak load over longer pull stroke. Must minimize shock if a kickback occurs. I think lots have smart coils now.