How to Repair a Lawn Mower without a Technician?

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A person always wants to have his lawn with a flat and even surface of grass. This gives the lawn a very beautiful appearance to behold. However, a flat surface doesn’t happen all by itself. And there the lawn mowers come by. In fact, this is an important part of proper lawn care.

But the very best one you got for your lawn may also have some functioning problems. If that happens, you may think of consulting a technician at first. But how about repair the mower on your own? If you want to repair the mower without the help of a technician, then this article will come to use for sure.

There are some common and typical problems occur in the mower. Before start repairing, you must know about some typical problems that tend to take place with a lawn mower. Then you can go for how to repair a lawn mower. In this article, I tried to provide some of the most usual problems and corresponding solutions. I am sure that you can fix these kinds problems by your own with ease after going through this article.

How to Repair Your Lawn Mower?

You may think that why your mower is not working altogether even after buying the best possible one. As a matter of fact, as a simple and seasonal machine, a lawn mower gets filled with dust and dirt. Again, long storage tends to jam the mechanical parts which cause some problems as well.

Now, check out some usual problems along with their respective solutions below. By knowing the problem type with your mower, it will be easy for you on how to repair a lawn mower. And again, you will be able to fix that without a technician.

  • Lawn Mower Doesn’t Start

This is the very first problem when it is about how to repair a lawn mower. After keeping the mower in a storage for some time, the engine may not start. It is the most common problem that takes place with a lawn mower. Cranked spark plug, clogged carburetor mainly cause this. Also, old fuel, bad fuel pump, broken flywheel key, defective ignition coil, and pulley make the mower subjected to this start-up problem.

  • Lawn Mower Starts but Stalls

Apart from startup problem, there is also a common problem related to startup which stalls engine after starting it. Moreover, it may start once and then refuses to get started. Like the previous startup problem, almost same ingredients are responsible for causing this. You need to take care of spark plug, carburetor, fuel, fuel pumps and all other contributors to start the mower.

  • Lawn Mower Battery Drains Fast

Sometimes the battery of the lawn mower runs out pretty fast. With a mower like that, you have to keep yourself busy charging the battery rather than taking care of your lawn. Along with dead battery cell, defective charger and alternator, bad voltage regulator mess up with the battery.

  • Lawn Mower Doesn’t Self-propel

When you start the engine, there is a possibility of getting shocked to see the self-propelling not working. It is a good problem to remind that smaller parts have same importance like big ones. Bad or worn out V-belt, wheel and transmission assembly, drive pulley may work behind this problem.

  • Lawn Mower Becomes Hard to Start

It is possible that your lawn mower takes start but only after a good effort. This will make you uneasy with the mower as it requires more effort over time. Similar to startup problem, bad spark plug, fuel, the carburetor may cause this. Flywheel key, ignition coil, and pulley as well are accountable for having this problem.

  • Lawn Mower is Overheating

For any devices with engines have a common issue regarding its operation – that is overheating. A lawn mower is also subjected to this issue as well. Additional air-cooling fins inside the engine work against overheating. Failure of those fins may cause overheating of the engine.

  • Lawn Mower Blades Don’t Engage

While you gear up the engine, you would like to watch the mower cutting down the grasses of your lawn. But without blade engagement, it is impossible to rotate the blade. Moreover, the problem of both PTO clutch, as well as PTO switch, can resist proper engagement of blades.

  • Lawn Mower Runs Rough

It is also related to startup problem mentioned earlier. This problem makes it very difficult for the user to run the mower with comfort and makes the blade deficient to cut grasses. Bad spark plug, carburetor, fuel, fuel pump, flywheel key all these are responsible for causing this roughness issue.

  • Lawn Mower Leaks Gas

While using the lawnmower, you may notice that gas leakage is taking place from the engine. Although it is not as dangerous as gas pipeline leakage, you need to stop that. You need to look at the carburetor bowl gasket as well as the float needle as they are mostly responsible for this leakage. Also, fuel filter, fuel line, and primer bulb may also cause leaking gas.

Repairing Your Lawn Mower by Yourself

Also, there are some other problems regarding how to repair a lawn mower that may take place with your lawn mower. But they are either not that important to mention or too complicated to handle for the user to repair. If you have problems mentioned in the above, then you can check out some parts and their respective cure below.

  • Cranked Spark Plug

When it is time for how to repair your lawn mower, look at the spark plug for any wear or damage signs at first. In the case of, cracked porcelain insulator, it is possible to have an electrode damaged or even burned away. But also, piled heavy carbon at the electrode may cause a severe problem. This includes startup along with stalling problems.

To reveal whether the spark plug is defective or not, it is better to use a spark plug tester. While the engine cranks, you will see a strong spark among the terminals of the tester for a good one. Without any significant spark, the spark plug indicates that the plug is faulty. You need to take out the plug from its connection to change the older plug with a new one.

  • Clogged Carburetor

The carburetor is an integral part which may also mess up with the startup. If the carburetor becomes clogged, then the startup will not function. It takes place due to left fuel in your lawn mower for a bit longer time. With the passage of some time, some of the ingredients of fuel may start evaporating. Thus this process leaves thicker and stickier substances behind that clogs up the carburetor.

Clogged carburetor offers you some common problems like start-up as well as stalling. For a clogged carburetor, you need one carburetor cleaner to use. Then clean up the entire carburetor if possible. You need to be careful while cleaning this. Sometimes, cleaning up the carburetor may not work as well. In that case, you should replace or rebuild the entire carburetor.

  • Defective Carburetor Bowl Gasket

Carburetor bowl gasket lies at the bottom of the carburetor. If the gasket dries out or goes missing, then there is high-risk of having a leakage. In general, gas comes out through the leakage. This issue also concerns how to repair the lawn mower.

For a deficient bowl gasket, you need to take out the carburetor at first. Then separate the bowl gasket from it. If it is defective, then make a replacement to stop gas leakage.

  • Bad or Sophisticated Fuel

When there are old or sophisticated gasoline in the carburetor, you can sure that you will not get a good performance. However, the bad fuel contains some ingredients that are harmful to the engine. In addition, this gasoline leaves a thicker substance with the evaporation of some ingredients.

This also is responsible for causing start-up, stalling problems. In this case, you should remove the gasoline from the mower. Otherwise, you can clear the float bowl properly to make the startup working.

  • Damaged Fuel Pumps

A fuel pump comes with 3 parts – pulse port, gas in port and gas out port. One small tube of rubber connects the pulse port with engine crankcase. The tube gets alternately pressurized and depressurized through the crankcase air when this engine is running. The pressurized air moves to pump diaphragm for pumping the gas. For an overfilled engine, oil may enter pulse port line restraining it from working. Apart from this, 2 small check valves at both input as well as output ports. Any of these 2 can fail.

To check out whether the fuel pump is working or not, you need to take a look at the entire fuel pump. Take a good look at the port line, valves and the diaphragm as well inside the pump. For a defective one, disconnect all the wires and then remove it from the engine. But you need to keep in mind that you can’t fix a fuel pump even if you want to. You must replace the pump in order to start up the lawn mower.

  • Clogged Fuel Filter

A clogged fuel filter occurs when you leave old fuel to run the lawn mower. Like bad fuel, some ingredients evaporate from that old fuel. This leaves a pretty sophisticated substance for the engine. This sticky fuel is responsible for making the engine rough to run.

In the case of old fuel which you left, try to drain out the entire fuel or whatever left from the fuel tank. Take out the fuel filter to observe if it is still good or not. If not, you are so out of luck. However, you should place a new filter with the older and damaged one.

  • Clogged Fuel Cap

Fuel runs the engine and itself gets lowered. To keep up with this, every fuel cap consists a small vent to make it possible for air to enter the tank. Thus the vent of fuel cap becomes clogged due to lack of air inside the tank. As a result, a vacuum will take place inside the fuel tank. This prevents the continuous flow of fuel to the carburetor. In this case, the engine will start but will stall then.

If you want to look whether the cap vent is clogged or not, you need to loosen the cap slightly. After that, try to start your engine. In the case of running engine with slightly loosen fuel cap, you can say the cap is defective. For clogged one, take out the fuel cap with care. You need to replace that with a newer one.

  • Broken Flywheel Key

Flywheel key is a small piece of metal that fits into crankshaft and allows it to engage with the flywheel. Thus it enables the mower engine to prevent any damage. If the mower hits any hard material during mowing, this key may get sheared in pieces. With a broken flywheel key, the mower engine will stop instantly and it will not start again.

To find out if the flywheel key is broken or not, remove the key with care from the engine and then observe. Concerning how to repair a lawn mower, you should replace it with a new one.

  • Worn out PTO Clutch

The Power Take Off (PTO) clutch offers the chance to disconnect the engine from the blades manually. With the clutch solenoid energized fully, it engages the drive belt. This engagement results in driving the lawn mower blade rotation. For defective or worn out clutch solenoid and for not getting power, mower blade will not engage.

If anything defective takes place with the PTO clutch, take out the clutch from all connections. Not being repairable, you have to go for a replacement in case of the worn out clutch.

  • Deficient Transmission Assembly

The drive belt powers the transmission of the mower at the first place. Again, this belt connects it with the engine crankshaft. The drive belt powers the transmission and enables the lawn mowers wheels to turn. The defective transmission will cause the mower not to self-propel.

To observe whether the transmission is defective or not, you need to watch the transmission with care while the engine is running. When transmission pulley spins but wheels don’t turn, you need to take the transmission out for a replacement.

  • Clogged Cooling Fins

Almost all air-cooled small engines come with cooling fins. It is placed right into the engine cylinder head and short block. All these fins encourage to dissipate the engine heat. If these fins get clogged with grasses, leaves or any other debris, then fans will fail to address the heat. This will lead to engine overheating problem very soon.

If the engine becomes overheated, take out the engine cylinder while the engine is not running. Look for debris or grass inside the fins. If you find clogged debris, take those out carefully. Otherwise, you need to change the cooling fins for its mechanical error.

  • Defective Ignition Coil

This coil sends voltage to spark plug while the engine is working. For a defective ignition coil, the engine may not start as well. You may check the coil with an ignition coil tester. If you find the coil to be defective, replace it with another one. Make sure that spark plug is working before replacing the coil.

  • Defective Float Needle

The float needle is a small part which alternately opens and closes the float valve. Thus it allows fuel to get in the float bowl. In the case of, damaged float needle, the carburetor will continue to fill itself with fuel unless it overflows. It may cause the carburetor to leak gas.

To find if the float needle is defective or not, watch out the carburetor while the engine is running. If the needle is defective, take out the entire carburetor. Then replace the needle with a newer one.

  • Rewind Pulley and Spring

When you pull and then release the starter rope, this rewind spring recoils starter rope onto another pulley. If the rewind spring breaks, the rope will not recoil onto that pulley. As a result, the engine won’t start.

If the rewind spring breaks, you have to change it. You can make this change for either individual springs or the overall pulley and spring assembly.

  • Broken or Worn out V-belt

A v-belt does the work of rotating drive pulleys. It enables the mower to drive the wheels. If this belt becomes broken or worn out, it will affect the wheels and the wheels will not turn.

In this case, inspect the v-belt of the mower with care. If you find it defective, take it out and make a change with a new one.

  • Stuck Starter Pulley

This pulley encourages to wind up the starter rope while the mower is not in use. For sticking up or broken pulley, the startup won’t work.

In the case of a stuck pulley, you need to free it with care. But for broken one, you must change it concerning how to repair the lawn mower on your own.

  • Dead Battery

One or even more dead cells in a battery is a common phenomenon. This causes the mower battery to charge out in a matter of seconds. Charging the battery through a battery charger works well for battery maintenance. You should give it a try in the first place.

However, if the battery can’t still hold the charge, it indicates defective battery usage. For that, you need to change the batteries.

  • Defective Alternator

A defective alternator is an important issue how to repair a lawnmower. In fact, an alternator delivers voltage to the mower while the engine is in operation. It also helps to recharge the battery. The charge of your lawnmower may go down fast due to the deficient alternator.

You may test charger outlet and make sure that the outlet doesn’t have tripped any breaker. If the alternator is defective, you need to make a suitable replacement.

  • Deficient Voltage Regulator

The voltage regulator supplies necessary amount of voltage to the battery from the alternator. This enables the battery to remain charged. But defective regulator results in sending necessary voltages to the battery. Thus allowing the charge to drain fast. For a defective regulator, you need to take out the voltage regulator at first. Then take out its connection with the engine and make a change with a new one.

Final Words

It is not easy for anyone to fix problems who is not similar to repairing mechanical devices. Regarding how to repair a lawn mower, fixing normal problems is not that complicated though. But you need to know well about the parts to do the fixing. It is true that some of the parts have very sensitive connections which you need to take care of. Apart from only the simple ones, it would be better to go for a technician for really complicated problems. I can assure you that with proper concentration you will be able to fix all those problems mentioned above.

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James Patrick

Hi, My name is James Patrick. Gardening is my passion and blogging is my profession. I make this blog to share my gardening experience here. Keep on your eyes here :) to get the latest gardening tips.