A lawnmower is like a magical hand to keep the surroundings neat and clean. Every time we start this device, it helps organize the garden while removing excess garbage, weeds, and grasses. Therefore, a new riding mower may give us the optimum performance. But it is aged, like 2-3 years, it can be too troublesome. A common problem can be that a lawnmower won't restart when hot. Hence, there are lots of reasons behind the mower's failure to start that we should know.

So, why doesn’t a lawnmower start after replacing the head gasket or when it’s hot? Multiple reasons make the mower engine failure to begin well. Some significant reasons are an overheated engine, faulty choke error, defective spark plug, air leakages, low or empty oil, faulty ignition coil, or carburetor failure. Whatever the reason is, you should inspect the problem first before taking any remedies.

I have seen many owners of lawnmowers facing several starting problems. They call the experts even without knowing why the lawnmower clicks but won't start. I recommend reading this blog post and trying to sort out the problem yourself. You will get answers to these problems:

• The lawnmower won't restart when hot.

• The lawnmower won't start after replacing the head gasket.

• The lawnmower clicks but won't start.

• Why is my lawnmower turning over but not starting?

Why is the lawnmower Won't Start? Finding the Reasons & Possible Solutions

A healthy mower means a healthy lawn. But when it doesn't start well, we get things dirty, scattered, and unpleasing. It's not like the fuel is finished and the machine is not starting for it. Sometimes you fill the fuel tank full, and still, the engine may click but won’t start.

Anyway, there are multiple reasons why lawnmower turns over but do not start like these:

Overheated Engine

If your engine turns out hot desert, it will not start like before. Not only the scorching summer, but there are also several other reasons why your engine gets overheated. Here are some of them:

• Grass clippings and debris can clog the cooling fins. These fins are precast into the engine's block.

• You may see there is a plastic housing that covers the lawnmower top. It can trap dirt so that engine stops and increases its temperature.

• If you use the off-beam plug or fuel, it may mutilate the cooling fins. Then, your machine fails when it becomes hot.

• The muffler may also get clogged by grass clippings. As a result, the engine becomes hot.

To solve the problem, it is better to remove the plastic housing. Also, it would help if you kept out the twigs and debris with an air compressor. After that, your lawnmower will start.

Air Leaks

The gas-to-air ratio in an engine may impact the performance of the riding mower. Any air leakages will cause the mower starting failure if there are any air leakages. Think like your engine has got air leaks. So, it makes an entry for external air that will change the regular ratio of gas to air. This imbalance causes the engine to run improperly.

An engine gradually increases its temperature when using the lawnmower. After getting hot, remotely placed units on this device start expanding. Then, larger leaks or gaps happen. Usually, loose bolts cause these leaks. You should tighten all existing bolts properly. It will keep the carburetor tightly.

Spark Problem

You can find the tiny distance between the spark plug's two electrodes. When a spark passes this gap, the mixture of air and gasoline combusts. As a result, the engine gets its proper power to run further. But when the length of the spark plug is incorrect, that combustion can increase the width of the gap. Then, the mower engine shuts down.

You should read the instruction manual for the lawnmower. Then, set the gap accordingly. Besides, change the spark plug if the carbon malfunctions. Sometimes changing the condenser and the ignition coil may also work.

Malfunctioned Carburetor

Around 75-80% of lawnmowers fail to start for faulty carburetors. Usually, the choke of the carburetor opens when you start the engine. If the carburetor has malfunctioned, it will remain shut for the sticky choke. Then, the engine gets flooded.

So, it would help if you inspected all the choke linkages. Then, clean all to keep the choke active. You may use a solenoid (electric) for some brands or models. But always try to maintain the health of the device.

Faulty Choke

A faulty choke causes a flooded engine. As a result, the heat dissipation rate decreases, and the engine gets hotter. For some severe cases, there can be an unexpected fire outbreak. If you can identify the issue, remove the air filter first and clean it. For automatic choke, you may need to replace the carburetor.

Oil Level

You may find it unusual that oil level can be a reason for high engine temperature. But some brands may fail to start appropriately if the fuel tank is lower. That's why you must check the level of oil. If the tank is empty, fill it correctly. One more thing, most lawnmowers have 0.6 liters or (5w30/10w30) gasoline capacity.

Flat Battery

A flat battery can cause lawnmower clicks but won't start. Possibly, the battery has leaked after running the machine for a long time. Again, excessive acid buildups can reduce the lifespan of the battery.

Check the electrolyte level and then fill the battery if necessary. If you see excessive leaks, replace the battery; otherwise, a jump-start can solve the problem. You should make sure of the fitness of the battery and the proper placement of the poles.

Battery Connection Problems

You may think, "why is my lawnmower turning over but not starting?" Here is a reason: faulty battery connections. It can prevent a lawnmower from turning on well. After all, the defective connection resists power transfer from the battery to the whole device. If you see the machine vibrating, check if the connections are loosened. Also, identify any chalky substance on those connectors.

Tighten all the connections while maintaining positive (red +) and negative (black -) cleanliness. Change or repair damaged or corroded cables. Thus, you can use a paste of baking soda and water to apply to acid buildups. Then, clean the connectors using sandpaper or a steel wool brush. Applying some petroleum jelly may also prevent the buildups.

Solenoid Faults

The duty of the starter solenoid is to arrange connections between the battery and the starter motor. Also, the 12V power supply activates the solenoid that travels from the ignition switch. Later, the engine cranks when you hold the machine key properly for the solenoid. If you hear any clicking sound, it means the solenoid is working but failing to work.

Usually, solenoid remains under the lawnmower hood. If you don't get it there, check below the rear wheel, below the gas tank, or under the seat. After finding it, disconnect the battery, and fix it if you see any errors. If you still hear the clicking noise, you may need to replace the solenoid. Tighten all the solenoid terminals to start the engine again correctly.

Binding Starter Motor

It can cause a bad start for lawnmowers. A starter motor has a gear head that can get jammed against the flywheel. Then, the engine and the starter motor bind together. As a result, the lawnmower clicks but won't start.

Test the starter motor to solve the problem. First, you should turn the engine over by hand in an anti-clockwise motion. If your machine has a covered flywheel, you can try to rotate the crankshaft using a ratchet and a socket. Spray some WD40 on the started gear head and see the result; everything will be solved.


If your lawnmower won't restart when it's hot, the problem could be with the spark plug, fuel line, or carburetor. You'll need to troubleshoot each of these components to identify the issue. Once you have found the problem, you can make the necessary repairs and get your lawnmower running again.

You may also try other methods or test the device to have the problems mentioned above. After identifying the problem, you can solve the situation accordingly. After all, regular maintenance is the best way to prevent a lawn mower won't start after replacing the head gasket.