Lawnmowers consist of a set of rotating blades, a basic combustion engine, wheels and a handle. Even a new mower can fail to start. To determine the cause of your mower failure, run through a checklist of what could be wrong. Always begin by reading the manufacturer's instructions for starting your machine.
New mowers have never been started before. Fuel has never made its way through the inner workings of the engine. For this reason you must prime your engine prior to starting, or it may not work. Priming the engine pushes a small amount of gasoline into the cylinders where it can ignite when you pull the starter cord. The primer is most often a small rubber button that looks like a ball and that should be pressed the amount of times recommended by the manufacturer.
If your new mower has been sitting at the retailer's or in the garage for some time without being used, it may contain stale gas. If it has been rained on or the tank has been left open, there may be water in the gas. Either drain and replace the gas, or use a gas-line antifreeze or dry gas additive to correct the issue. Ensure there is enough fuel to feed the engine properly.
If you have a 2-stroke lawnmower, you will have to mix your gas and oil before placing it into the tank. Four-stroke machines require only normal gasoline, but 2-stroke mowers need a blend specific to each machine as instructed by the manufacturer. If you have too much oil and too little gas, the engine may not start.
Open the Choke
When starting a carbureted engine, you must often open the choke. The choke allows more air into the carburetor -- and, by extension, the engine cylinder(s) -- than normal. This increase in airflow causes the fuel to burn hotter and faster and helps to get the engine started. Once the engine is running and warm, you should normally close the choke most of the way to maintain a clean and efficient engine cycle.
Examine the engine for a fuel cutoff switch. Some mowers are equipped with such a switch as a safety precaution to prevent leaks. Many mowers are also equipped with electrical cutoff switches so that the person using the mower may kill the power whenever necessary. Cutoff switches are also installed by manufacturers to prevent accidental starts on machines with electronic or key starters.