One of the most common features of most gas-powered push mowers is the cord or rope that you use to get it started. But why do they have pull cords rather than some other starting mechanism?
The pull cord on a gasoline lawnmower is part of the recoil starter system that is used to get the engine started. By pulling the cord, the operator turns the engine over and ignites the fuel mixture without the need for a battery.
Read on to find out exactly why the pull cord is such an important feature and why electric mowers don’t have them.
What Does A Pull Cord Do?
Pull cords are a reliable way to start a gas mower’s engine, without the need for a battery or any other form of power. They use the force created by you pulling on the rope to both turn the engine over and create an ignition spark.
To understand why pull cords were invented in the first place, we need to know how a lawnmower engine works.
Most traditional rotary push lawnmowers use internal combustion engines, just like your car. However, unlike your car that relies on an electric starter motor powered by a large battery to get it going, lawnmowers use a far simpler, mechanical method – the pull cord.
The pull cord, also known as a rope start, is part of the recoil starter, an ingenious solution to start the engine. When you give the cord a strong pull, it sets the lawnmower’s flywheel in motion, which in turn spins the crankshaft.
This motion makes the pistons move and create a vacuum, triggering a chain reaction in the engine. First of all the vacuum draws in a mix of fuel and air into the engine’s combustion chamber.
The spinning flywheel has magnets on it that interact with the ignition coil to generate a spark at the spark plug, igniting the fuel-air mix in the combustion chamber.
This ignited explosion generates power, propelling the piston to move and creating a self-sustaining cycle of energy production. This cycle keeps the mower running until it either runs out of fuel or is switched off.
In simple terms, the pull cord is a manual starter that’s simple, reliable, and cost-effective. Due to its mechanical nature, it doesn’t depend on any additional power source, which comes in very handy for a tool that’s frequently used far from power outlets.
How A Recoil Starter Works
A recoil starter mechanism allows you to pull on the starter cord to crank the lawnmower engine, and then automatically rewinds so that you can quickly give it more pulls if needed.
Understanding the mechanics behind a recoil starter, pull cord system, rewind starter, or whatever else you want to call it is quite fascinating.
A brilliant but simple piece of engineering that has stood the test of time, a recoil starter consists of just a few key components: a rope (the pull cord itself), a spring, a pulley, and usually a locking mechanism.
The cord is wound around the pulley, which is also connected to a spring. When the cord is pulled, the movement causes the pulley to spin and the spring to unwind.
Now, here’s where the magic happens. The pulley is connected to the lawnmower’s flywheel via a small set of gear teeth or a similar mechanism. As the pulley spins, it engages these teeth, causing the flywheel and crankshaft of the engine to turn. This in turn sets off the series of events required for the engine to start.
Once the engine starts and the cord is released, the spring recoils, rewinding the cord around the pulley and disengaging the gear teeth from the flywheel. The engine then continues to run on its own until it’s either turned off or runs out of fuel.
To sum it all up, the pull cord system—or recoil starter—is a manually operated device that converts a pulling motion into a rotational force.
It’s a beautifully simple and effective mechanism that combines the basic principles of physics with clever engineering to start your lawnmower with a single pull.
Do Electric Mowers Have A Pull Cord?
The electric motor on corded or cordless electric lawnmowers does not need a pull cord to get it started. These motors jump into action with a simple flip of a switch or push of a button.
They are powered by a continuous supply from a direct electrical connection. You just need to connect the motor and the power through the starter button or switch, and this eliminates the need for a mechanical start mechanism like a pull cord.
This makes electric mowers far more user-friendly for a lot of homeowners. The push-to-start system is straightforward and easy to use for anyone, no matter their skill level.
However, it’s worth noting that electric mowers have limitations, such as less power compared to gas mowers, a dependency on power cords, or keeping an eye on battery life.
Do All Gas Mowers Use Pull Cords?
While most gas-powered mowers in use today come with a pull cord, some modern machines also now come with an electric starter for added convenience.
A key alternative to the recoil starter is the electric start feature found on some high-end gas-powered mowers. These mowers are equipped with a small electric motor and battery, similar to what you’d find in a car but on a smaller scale.
All you need to do is turn a key or press a button and the electric motor will turn the crankshaft, get the pistons moving, and initiate the internal combustion process. It’s a much easier method that’s less physically demanding compared to the traditional pull-cord system.
Still, it’s important to remember that electric start gas mowers require a battery to power the electric motor. This battery needs regular charging, an additional task not needed with a rope start mechanism.
As lawnmower technology progresses, we’re seeing features like electronic starter systems becoming increasingly popular. However, often you will find that these mowers also come with a recoil starter as well, just in case!
So now you know why gas lawnmowers have pull cords. Their simplicity, reliability, and effectiveness have made them an enduring component of lawnmower design that will probably never disappear.
Modern technology may give us far easier ways to start the engine on your mower but it’s unlikely manufacturers will stop including the manual recoil mechanism as a backup anytime soon.