How Does a Lawn Mower Engine Work?

With the exception of the more affluent of us we all know what a lawnmower is and how they work. But do your truly know how that engine on the mower works? No matter whether you turn a key, pull a rope or push a button you need to know how it operates.  What actually makes it work?

Starting the Mower

What exactly happens when you push that button or pull the rope? No matter a four stroke or a two-stroke engine, they all start the same. There must be a combination of fuel, a spark and air combining together to start running. The starter consists of a flywheel and clutch. The action of pulling the rope or using of an electric motor activates them. The clutch spins the flywheel allowing air and fuel into the combustion chamber and causes a spark to ignite the fuel.

The Carburetor

The carburetor actually controls the flow of air and fuel into the combustion chamber. The throttle of the mower is attached to the carburetor as well, if the mower is so equipped. In many newer mowers the operator must actually “prime” the carburetor by pushing a bulb several times to get the carburetor ready with fuel. They may also have a “choke” enabling quicker starting in colder weather.

Combustion

This takes place in the engine piston and spark plug area. As mentioned earlier in four-stroke engines this takes place with the piston in on the upstroke. In a two-stroke engine, it takes place on both the up and down stroke. This is what makes the mower work. The piston (or pistons) are attached to a crankshaft which powers the mowers parts.

Operation of the Mower

Once the mower has started it is then fully functional. This will include propelling the blades, powering the wheels and other equipment, as the mower is so equipped.