Why is it that chainsaws need a pull cord to start? Couldn’t they just be turned off or on with a switch?

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Why is it that chainsaws need a pull cord to start? Couldn’t they just be turned off or on with a switch?

In: Engineering

The pull cord on a chainsaw (or a lawnmower, for that matter) starts turning the engine over, which produces the energy needed to kickstart the engine into motion.

If you had a switch…you’d close an electric circuit, but where would the electricity come from? What would make the engine turn on to produce the electricity?

In order to do that it would need to have a battery, an electric starter motor, and a coil to generate electricity to recharge the battery, all of which would add a bunch of weight which you don’t want with a handheld tool.

I see all the stuff about electricity, which is true, but also a switch can easily be accidentally flipped or flipped by an unsupervised child.

You could build in an electric starter to your chainsaw but then you’d have to haul around the electric motor and the battery, which adds a lot of weight and bulk (and cost). An engine that small is easy enough to start that getting it going by hand usually isn’t an issue, so it’s not worth the headache that a self-starting unit would have.

To add to other answers, in the beginning cars didn’t have starters either, and had to be crank started. This was dangerous since once the motor started, the crank would turn with it…