“Why is my lawn mower turning over but not starting?” is a question we get a lot from lawn owners. This is a common problem that may arise for a number of reasons.
The good news is that it is very easy to figure out why a mower is not starting despite it turning over. Read our comprehensive list of all these lawn mower faults and their easy solutions in this guide.
Contents
Why Is Your Lawn Mower Turning Over But Not Starting?
Your lawn mower turning over but not starting due to several reasons, such as a faulty or disconnected plug, a disconnected spark plug wire, a clogged air filter, or a contaminated fuel tank. A faulty carburetor, a dirty cutting deck, or a dysfunctional flywheel brake can also cause this.
– Problematic Spark Plug
The most probable cause of a mower not starting properly might lie in a problematic spark plug. This plug is responsible for producing the spark that ignites the fuel in the engine.
This plug usually stops working when it becomes loosened or disconnected and cannot generate a spark. Over time, it can become coated with carbon or water residue and stop working properly. It is very easy to fix a faulty plug – you simply have to take it out and visually figure out where the problem lies.
– Wire Not Connected to Spark Plug
If the spark wire is not in close contact with the plug, the lawn mower naturally will not start, regardless of how hard you try. If the rubber cover over the plug is not placed properly, then this will also prevent the wire from contacting the plug. You will need to check the plug and the wire without removing either of them to see if this is where the problem lies.
– The Air Filter Might Be Dirty
The purpose of an air filter is to let air inside the engine so that the oxygen in it can help combust the gas and start the engine. Over time the airflow into the engine gets compromised because of a dirty filter.
The filter naturally collects things like dirt, dust, and other impurities. Eventually, it becomes so clogged that it stops all but a little air from entering the engine.
Usually, this filter is located near the top of the filter and is covered by a plastic or metal coating. You will have to unscrew the coating to get access to it.
– An Empty or Contaminated Fuel Tank
An empty gas tank can commonly cause this problem. Also, if the gas in the fuel tank has been left standing for too long without changing, then such a fuel tank will not catch a spark either. Even if the gas is just one month old but is being used without a fuel stabilizer, you will face this problem.
Similarly, a gas that has somehow been contaminated with dirt or moisture is useless and will not work.
– A Faulty Carburetor Filter
Another common reason why push-type or riding lawn mowers do not start despite turning is a carburetor that’s filled with too much residue. That is why it is recommended that carburetors be cleaned up at least once a year as part of regular maintenance.
This is not such a common problem. That is why you must first check that the ignition switch, air filter, etc., are working properly.
Another common sign of a clogged carburetor is that the engine might turn and start stalling. There might be black smoke emitting from the muffler. There will also be increased fuel consumption by the machine or weird noises from the engine.
Weird sounds like something splashing in the engine also means something is wrong with the carburetor. Other signs are the engine backfiring or being unable to accelerate.
– The Mower Deck Might Need Cleaning
The concept of a cutting deck is that it collects grass clippings and prevents them from spraying into the air. However, these clippings eventually clog up the mower and prevent the blade from cutting grass.
This especially happens when you habitually mow wet grass because such grass clumps together. That is why mowing dry grass is better for the lawn and the lawn mower over the long run.
– The Flywheel Brake Might Not Be Working
The purpose of a flywheel brake is to keep the engine running smoothly. They also help cool the engine and maintain the speed of the power strokes.
When the riding mower hits a hard spot, the brakes help absorb some of the damage. If your flywheel has been damaged, the mower won’t start but will, in fact, turn.
How To Fix a Lawn Mower That Is Turning Over But Not Starting?
To fix a lawn mower that is turning over but not starting, you can fix your spark plug, clean the airway filter, clean the fuel tank, fix the carburetor fuel filter, clean the mower deck, and repair the flywheel brake.
– Fix Your Spark Plug
First of all, find where the faulty plug is located. Usually, it is present at the front of the mower. Disconnect the plug wire to reveal the plug present underneath. You will likely need a wrench to unscrew the plug and take it out for observation, especially the insulator and the electrode on the plug.
If it is dirty with residue build-up, then only an easy clean-up is needed. Use a brake cleaner spray on this build-up, let it stay there for a few minutes – so the dirt gets dissolved – and then wipe it off with a clean cloth. Reinstall the plug in the machine and see if the problem has been resolved.
In some cases, you will need to change the plug with a new one. See if the electrode is missing or burnt or if the plug coating has been compromised. You can easily find new spark plugs at a reasonable price at any hardware shop.
– Connect the Spark Plug Wire Properly
If the problem lies in the wire not contacting the plug properly, then all you need is to connect the two. See if the rubber coating on the plug appears loose and pushes down in that case.
Tighten the rubber covering and also make sure that the wire is exposed enough to make adequate contact. If the rubber covering has been burnt, torn, or damaged in any way, then order a new one and replace the old one.
– Clean the Dirty Air Filter
If your machine won’t start because of a clogged air filter, then all you have to do is to clean it. Before unscrewing and removing the covering to the filter, you must disconnect the spark plug first. Then remove the metal or plastic encasing protecting the filter.
Take the filter out and inspect it carefully before cleaning. In the case of a paper filter, tap it gently on a flat surface to remove dust and dirt. Hold the filter up to a light source and see if it is blocking light from it. If so, replacing the filter with a new one is best.
In the case of a foam filter, use water and any dishwashing soap to cut grease and remove dirt. Squeeze it to remove all extra water, and then dry it thoroughly. Apply oil to your hands and use it to lubricate the filter thoroughly. Ensure that the oil is not dripping off the filter but only lightly wetting its surface.
Before reapplying for a clean filter, you should also cover the fitting with which the filter will be attached. Only use dry cloth because using compressed air or solvents might damage it. Replace it carefully and then cover it with its covering that has been cleaned as well.
– Clean Your Fuel Tank
If the problem lies in bad gas within the fuel tank, then you need to take it out. Use an oil siphon pump to drain the old gasoline out. Use the good old gravity method if you do not have a pump. Disconnect the carburetor from the fuel tank and place a container underneath to collect the gas.
Be careful not to spill the gasoline anywhere because this can lead to several problems. After your tank is emptied, it is time to clean any impurities. First, use only boiling water to wash the inside of the tank, and then use water mixed with a good quality fuel detergent.
Use a brush to scrub the inner walls if impurities are stuck. Give a final wash using clean water, dry the tank, and then refill it with fresh gas. This time add a fuel stabilizer to the gas to keep it from going bad.
– Fix the Carburetor Fuel Filter
Before cleaning the dirty carburetor, it is better to clean the outside of the mower beforehand. In most riding mowers, the carburetor lies on top of the air filter, and you will need to disassemble it and take it out in order to gain access to the carburetor. For other mower types, use the instructions manual to find out where and how to gain access to it.
You can use a carburetor cleaner to clean the insides of the carburetor bowl while it is still attached to the mower. To clean it thoroughly, however, you must take the carburetor out. Unscrew the nuts first and then disconnect the cables attached to them.
Before disconnecting the fuel cable, put something underneath to collect the draining fuel. Notice the carburetor’s position so you know where to put it back.
One way is to spray carburetor cleaner all over it and allow it to soak for a while. Give it an hour until all the grime and grease get dissolved, and then rinse off with clean water. You can then allow the carburetor to dry in the air or speed up the process using a blow drier.
Please do not put the carburetor back until all its parts are completely bone dry. Make sure that everything is back exactly how it was beforehand.
– Clean the Mower Deck
If your blades seem unable to rotate and cut properly, it might be time to clean them. In fact, the deck needs to be cleaned at least twice during each regular mowing season. Cleaning the deck is a piece of cake, but you must do it properly.
Either run the mower or the lawn tractor for as long as it takes for the fuel to run out. Otherwise, you can drain the fuel yourself by collecting it into a can. Disconnect the plug that starts the engine because you should not risk the lawn mower starting accidentally while cleaning the blades.
Tip the mower on a flat surface over its side, making its blades easily accessible. The easiest method is to use a hose to blast the blades at full speed. Most of the grass clippings and dirt will be forced off by this alone. Then use water, soap, and a sponge to scrub off all the rest of the dirt stuck on the deck and the blades.
Wash everything off using clean water and allow the deck to dry. A clever hack we employ is to spray some vegetable oil all over the deck lightly. Move the mower back into the standing position and reattach the ignition plug. Start the mower to see if it has started working now.
– Repair the Flywheel Brake
First, check the brake pad to see if it makes adequate contact with the flywheel. Also, check if something is blocking the cutting blade and preventing the flywheel lever from moving freely.
Sometimes the flywheel brake’s covering gets torn when something particularly hard gets tangled in the cutting blades. You will need to change the brake in this case. In order to do that, the entire mower will need to be taken apart.
Frequently Asked Questions
– How Do You Clean a Lawn Mower Carburetor Without Removing It?
You clean a lawn mower carburetor without removing it by getting a commercial mower carburetor cleaning solution. However, in order to gain access to the carburetor, the filter that cleans the air going into the engine must be unscrewed first.
Make sure you have removed the gasoline from the fuel tank beforehand and disconnected the ignition plug. After gaining access to the carburetor, spray the cleaning solution into it. Allow at least an hour, so the cleaning solution dissolves all the grease.
Use a sponge or a brush to scrub the insides of the bowl as thoroughly as you can. Then use hot water to clean off the cleaning solution and all the dirt.
– How Do You Know if Your Lawn Mower Fuel Line Is Clogged?
You know if your lawn mower fuel line is clogged if the engine will take a long time to start after significant spluttering. The overall performance of the mower engine will drop drastically, and you will experience a lot of random stopping or braking while using the mower.
Especially while driving at low speeds, your mower will frequently come to a halt by itself. This naturally happens when the fuel line randomly blocks the fuel supply to the engine.
– How Do You Get Your Lawn Mower To Start After Sitting All Winter?
You get your lawn mower to start after sitting all winter by charging your battery. If the battery has rusted over the winter, use hot water to clean it up first and then charge it. You’ll also need to empty the gas tank if you haven’t done it before winter.
So if your gas tank still contains fuel, the new spring season is the time to empty it. The carburetor will need to be unscrewed first, and then you need to disconnect the line connecting it to the fuel tank. Collect the old gasoline dripping down from the carburetor into a container.
Next, you must fill the fuel tank with fresh and clean gas. Smelling carefully is one of the easiest hacks to check if the gas is fresh. Check the oil in the mower and refill it with clean oil. Lastly, we suggest you clean the mower thoroughly before starting it after a long break.
Conclusion
Congratulations, this marks the end of our complete article regarding why your mower might not be starting properly.
Here is a summary of all the reasons and their quick fixes:
- A faulty or disconnected spark plug is the number one reason why lawnmowers might not start. All you have to do is to fix it or have it exchanged in case it is beyond repair.
- If the air or fuel filter is not working properly because it has clogged over, it will also need to be cleaned or changed.
- A mower deck with wet grass clippings and grime should be washed off regularly to keep the mower going.
- If your blades seem unable to rotate and cut properly, it might be time to clean them.
We have discussed all the common reasons that stop a mower from starting despite turning over. If your mower is giving you problems, our guide will help you find out the problem and solve them in no time.
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