Need to cut the grass but having trouble starting your lawn mower? There is nothing more frustrating than pulling on your mowers rip cord trying to get the engine to start while standing in the summer sun and not hearing the motor roar to life.
There are many reasons why your lawn mower won’t start, the most common problems are with the carburetor, starter or gas system and have a variety of causes from wear and tear to malfunctioning parts! If your Toro, Husqvarna or BLACK+DECKER lawn mower engine is not starting see what our lawn care experts recommend!
In This Guide
Out Of Gas
One of the most common reasons your lawn mower might not be starting is your tank is running on empty. If your rip cord is pulling but the motor will not fire you might be out of gas! Unscrew the gas cap and look inside the tank, if you can’t see any gasoline you need to fill up your tank!
Sometimes the gas in the engine will become stale and create a gunk that prevents the engine from firing. If you haven’t changed your fuel in a while drain out the old gasoline, replace with fresh gas and try starting your mower again!
Prime The Engine
If there is gas in the tank then you might just need to prime the engine. After sitting for a long period of time the gas in the carburetor starts to evaporate. Pump the plastic primer a few times to manually push gas into the carburetor and your engine should start right up!
Can’t find the primer? Most lawn mower primers are red plastic bulbs found on the side of the engine, near the carburetor.
Priming the engine is important because it helps the engine start after a long period of sitting, without priming you might find your engine not starting at all!
Clogged Air Filter
If there is gas in the engine the problem might be with the air filter. Grass, leaves and other lawn clippings can clog the air filter and other parts of the engine and prevent oxygen from flowing to the engine. If your engine is not starting or only runs for a few seconds before stopping try to clear any clippings from the underside of the engine and check the air filter.
A clogged air filter can be fixed by replacing it with a new one. New air filters are cheap and easy to install, check your owner’s manual for specific instructions and the right model for your mower.
Dead Battery
Not every lawn mower runs on gasoline. Many green friendly mowers are now battery powered. If your electric lawn mower is not starting make sure the batteries are charged! Most battery powered lawn mowers come with 2 batteries so you can charge the spare in your garage while you are working!
Sometimes batteries will become drained if left too long and won’t charge up. If your batteries are not holding their charge it might be time to replace them!
Another common problem is if the batteries are left in the cold. Cold temperatures can really drain the power from a battery powered mower so if you are having trouble starting your electric mower in cold weather put it somewhere warm and try again.
No Power
Some electric lawn mowers are powered by extension cords. If your electric mower is not starting after turning the “On” switch make sure your extension cord is plugged in at both ends! If everything is plugged in check the length of the line for faults or places where you might have run over the cord with the lawn mower!
If your extension cord looks good try switching the cord and using a different power outlet to isolate the problem. If the extension cord is not the problem then you might have a faulty switch on your mower! If this is the case it is best to contact a lawn care professional for help!
Bad Starter
Sometimes the Starter will go bad or disconnect from the electrical system from wear and tear. A bad starter is difficult to diagnose but a quick trip to your local repair store should provide a diagnosis.
The starter is responsible for delivering the electricity to the spark plug that in turn ignites the gas and air mixture in your lawn mower engine. If you can’t get your mower to start it might be time for a new starter!
Full Bag
Many lawn mowers have clipping bags that hang off the side or back of the mower. If your clipping bag has not been emptied it might be disrupting the airflow and causing your engine not to start. Try emptying your bag and try starting the mower again, it should also be a little bit easier to push!
Some people prefer to mulch their clippings instead of collecting them in a bag. If you have been mulching your lawn it is possible the grass clippings are blocking the air filter or other parts of the engine and preventing it from starting. Try brushing away any clippings from the mower and check for any blockages!
Overheated Engine
If you have been using the mower for awhile in the Summer sun it might be overheated. Take a break and leave your mower in the shade or the garage for a little bit and take a break. Too much heat can cause a number of problems for gas powered engines, while they are designed to work outside sometimes it can be too much!
Don’t try to cool your mower with a garden hose! Blasting water at the engine will cool it down but the water can cause other problems inside the engine. Allow the mower to cool naturally in a shady spot before trying to start it again.
Stale Gas
Untreated gasoline can go bad if unused over a long period of time. If your mower or gas has been sitting in the garage or shed for over 6 months try running to the gas station and filling up on new gas!
Gasoline tends to last longer and perform better when treated with a fuel stabilizer. If you use your mower infrequently it is always recommended to treat the gas with a fuel stabilizer or empty the gas tank after each use!
Check The Oil
Lawn mowers, like cars, need regular oil changes. Check how clean your oil is by unscrewing the oil cap! If you can’t see any oil it might be time to change the oil. Lawn mower use SAE 30 weight oil rated rated SF, SG, SH, SJ or higher.
Oil is important for any gas powered mower because it lubricates the engine and helps reduce heat. Change your oil every 50 hours of use or once a year before winter storage!
Starter Rope Won’t Pull
There are a number of reasons why your starter cord might not pull. The first thing to check if you have a brand new lawn mower is that all the plastic safeties have been removed and that you properly followed the assembly instructions.
If your lawn mower is not new make sure the throttle is engaged and the brake has been disabled.
Starter ropes can become increasingly difficult to pull over time as they get worn down from use. If the rope is frayed, stuck or broken you might need to replace it.
Check The Safety
Many modern lawn mowers require the user to hold down the handle safety while pulling the starter cord and keep it held down while in use. If your safety bar is not going down or the wires have become disconnected your engine might not start!
Not every mower has a safety – and sometimes they can be hard to find so look closely! Double check that the safety bar has been engaged and wires are connected to make sure your mower is safe to start.