This refers to the system that uses a second "start" spring in addition to the normal cord rewind spring. When the cord is pulled, the engine gets harder to turn over as it approaches TDC and this causes the start spring to wind up, then when the piston goes past TDC the spring is released and kicks the engine over through another revolution, if the engine is going fast enough as it hits the resistance of compression again, it will get a spark out of the ignition and the engine will run. There is a critical amount of energy that must be stored and released by the spring, as the FW magnets must be traveling past the coil at or above the minimum speed required to create a spark. A common problem is some of these springs get weaker with use and can no longer drive the engine fast enough to do this, and it just stops when it hits compression. When this happens, the only way to get them started is to revert to drop starting, but this is a technique that is bound to destroy the starter, besides that, drop starting never feels right due to the mushy, lost motion feel of the cord pull. You are supposed to start these with just one smooth, even pull until the spring kicks the engine over, an instruction that is ignored by many owners. Cold starting can be an issue, even if the saw has a "primer" bulb and a good choke , it seems to take a lot of these 1-pop pulls to get a charge of fuel into the combustion chamber. The Poulan PP4218 and PP5020 with their helical spring are the worst, a marginal design to begin with and prone to early failure. I've modified many to return them to normal starting. Another innovation that's great when it works and gets owners swearing when it doesn't.
. No way I would ever recommend one…
