How To Fix A Lawnmower: 5 Common Problems
Lawnmower won’t start? While some lawnmower problems are preventable, others are inevitable.
It is important to learn how the mower works and how to fix a lawnmower at home. Always consult the owner’s manual for any mower before attempting repairs at home. If the mower is under warranty, consult the manufacturer before trying to figure out how to fix a lawnmower at home.
Common Problems And Lawnmower Troubleshooting Tips
Fortunately, it is easy to learn small engine repair and basic lawnmower repair when it comes to simple issues. Most problems can be remedied with a few tools, replacement lawnmower parts, and patience. To save money, always use these lawn mower repair tips for fixing a lawnmower at home before running out to buy a new mower.
The Starter Rope Is Stuck Or Is Hard To Pull
This problem is usually caused by the engagement of the engine flywheel brake. Check to see if the flywheel brake is pressing against the handle before pulling the rope again. When the flywheel brake is not the issue and the problem persists, check the lawnmower blade.
A rope that is stuck or hard to pull may be caused by the blade dragging on the ground or by clippings getting stuck to the blade. To address this issue, place the mower on a hard surface. Make sure the engine is shut off and the spark plug wire is not engaged. Carefully clean the bottom side of the blade to remove any clippings or dirt, put the mower back into position and try pulling the cord again. If the problem persists, one or more lawnmower parts may not be functioning correctly and will need to be repaired. Consult the owner’s manual or search online for repair guides for the specific model and brand of mower.
The Lawnmower Loses Power While Moving
At some point in time, nearly every lawnmower owner will be pushing the mower along and suddenly hear it sputter as the engine stops.
- One of the most common causes is a dirty filter. Use the owner’s manual to determine where the filter is. Remove the filter and clean it. If the filter is very dirty it may need to be replaced. This is one of the most inexpensive lawnmower parts to replace.
- If the filter is not the issue, compare the height of the grass to the mower’s cutting height setting. If the grass is tall, adjust the cutting height accordingly.
- Another way to fix lawn mower power issues is to clean the blade. Refer to the owner’s manual and use the manufacturers instructions to clean the mower blade.
- If this does not fix the issue, check the spark plug. Many people are able to quickly repair their lawn mowers by cleaning or replacing a spark plug. Spark plugs are also affordable mower parts that are sold online or in home improvement stores.
The Lawnmower Starts Smoking
This is one of the most startling issues to encounter – most people assume that the engine is about to die or blow up. However, this problem is usually not very serious. The engine often smokes when the chamber that holds oil is too full. Check the chamber to see if this is the issue. Another problem may be a leak in the oil chamber. If the mower leans to one side while mowing on a slope, the oil may leak out onto the muffler and cause the smoking. When the mower’s engine is off and has cooled, inspect the oil chamber area for leaks. The issue may be that the cap is not on tight enough. If the part must be replaced, it may be easier to look for the part online than to search for it in stores.
In rarer cases, the smoke may be a sign of a serious issue. If the smoke is white or very light in color and the mower does not run continuously, it is time to have a professional repair company look at the mower.
The Lawnmower Will Not Start
The first step in learning to repair lawn mower starting issues is to check the gas tank. An empty gas tank is the most common cause of a lawnmower not starting. Mower owners who are diligent about keeping their tanks full should still check the tank to see if there is a leak. If the tank is empty but should not be, inspect the outside of the tank for leaks. Replacement tanks can be found using an online lawnmower parts site.
Remember, in order to keep your fuel fresh if you’re going to be storing your lawnmower, use STA-BIL® Storage. It will keep your fuel fresh for 12 months and help protect the fuel tank from the effects of ethanol gas. Also, if there is a shut off valve for the gas lines, by all means, use it.
If the gas tank is not the issue because the mower runs on a battery, check the battery for signs of damage. Lawnmower batteries may also lose their ability to hold a charge as they age. Look for replacement lawnmower batteries if the battery needs to be replaced. Lawnmower batteries vary in price depending on the brand and model of mower.
Another important step in learning how to fix a lawnmower that will not start is checking the spark plugs. If they are dirty, clean them thoroughly. Reconnect them if they are loose. Old spark plugs should be replaced with new ones. If the fuel is not getting to the engine, knock on the carburetor’s side to help the gas flow again. If this does not fix lawn mower issues of this nature, look for a new fuel filter online.
The Lawnmower Loses Speed
When a lawnmower slows down considerably, the issue is usually a dislocated or damaged drive belt. This part is located in the motor casing. Consult the owner’s manual to verify the location. With the mower turned off, inspect the drive belt. If the belt is loose but not damaged, reattach it. If it is damaged, replacement belts are usually easy to find online from a lawnmower parts site. A new belt should repair lawn mower issues of this type. If the lawnmower runs on batteries, check the battery. Some lawnmower batteries may cause this issue if they malfunction, however, it is not common for lawnmower batteries to slow a mower’s speed.
How To Prevent Lawnmower Problems
Knowing how to repair a lawnmower at home saves time and money. The easiest way to avoid frequent problems is to maintain the mower. Follow these simple tips to keep the mower in good condition:
– Always use the correct type of replacement lawnmower parts. – Clean the blade regularly. Make sure to pull the plug so there is no chance that the blades can move while you’re cleaning them. – Oil any moving parts when needed according to the manufacturer’s instructions. – Change the oil as recommended. – Use the correct type of fuel. – Recharge lawnmower batteries according to instructions but avoid overcharging them. – Store the mower in a cool, dry and covered space when it is not in use. – Have the mower serviced as recommended by the manufacturer or warranty.
Lawn Mower Blade Bolt Stuck – Mechanics secret tips
I know the feeling, FRUSTRATION. but we’ll get it figured out. The blade bolt can be stuck for a few different reasons. Usually, it’s a combination of rust and over-tightening.
The easiest way to remove a stuck blade bolt is with an impact tool; they make the whole job look easy. Other options include:
You may not have an impact, so I’ll show you a few different options. Some of these options may not suit you; it’ll depend on what tools you have available. Best to don a pair of work gloves. Stuck bolts usually mean slipping tools.
Removing A Rounded Bolt
Over-tightening is common. Mower blades are designed to be tightened to a specific torque, which isn’t as tight as you might expect. That’s because they’re designed to slip if they hit a solid object. The slipping protects the engine from serious damage associated with a curbstone strike.
Also common is turning the bolt the wrong way; hey, it could happen to a bishop. All single-blade walk-behind mowers will have what’s known as a right-hand thread. That means, to loosen the bolt, you turn it to the left. (counter-clockwise)
I cover all you need to know pretty well in this post, but if you need more help, check out the following videos:
Blade Bolt Torque
Mower blade bolts should be torqued to spec. These bolts are usually over-tightened, and when you add corrosion, removing them can be a headache.
Only some large twin blades walk-behind mowers and some lawn tractor mowers are likely to have one only left-hand threaded blade bolt; the other bolt will be a regular right-hand thread.
How do you know which is which?
Simple, if the blade is designed to cut turning right (viewed from above), then it will be a right-hand thread; this is the most common type. To loosen a right-hand thread, you turn it to the left.
The same idea applies to twin-blade tractor mowers. However, a left-hand thread is common on some lawn tractor mowers.
So, if the blade cuts grass turning to the right, as before, it’s likely a regular right-hand thread (left to loosen). But it’s not uncommon for a tractor mower to have one of the blades turn to the left when cutting, and that usually means it’s a left-hand thread (check your owner manual) to loosen a left-hand thread, turn it to the right.
L/H – R/H Thread
A r/h thread loosens to the left. This is the most common type of thread. (counterclockwise)
A l/h threaded bolt loosens to the right. (clockwise)
Typical torque specs for blade bolts are anywhere from 35 ft. lbs. to 90 ft. lbs., you’ll need to check the spec of your mower, it’s important to get it right.
Most of the time blade bolts just get buttoned uptight and aren’t torqued to spec, and that’s OK, but you run the risk of bending the crankshaft if you hit a solid object. I advise using a torque wrench, it’s a lot cheaper than a new mower engine.
Torque wrenches are easy to use, they come in inch-pounds for smaller torque specs, but for mowers, you’ll need foot-pounds. A torque wrench from 30 to 100 foot-pounds is about right.
If you don’t have or can’t borrow one, check out this post on my 1/2 drive Teng Torque, it won’t break the bank, it covers 30 to 150 ft. lbs., it’s simple to use, calibrated from the factory, and has a flexible working range.
I get my torque wrenches calibrated every year but it gets a lot of use. If you set your torque wrench to zero after you use it and don’t throw it around, it should stay calibrated for years.
Damage – The bolt on the right has a rounded head, this kind of damage happens when a tool slips on a bolt head, or corrosion deforms it. Getting the bolt out presents a challenge.
A rounded bolt head is a real pain in jacksie. It usually happens when the bolt is old and corrosion has deformed it. Worn or damaged tools will give you the same result.
It can also happen if the wrong size tool is used. An American mower may use imperial size nuts and bolts, I know the more modern kit is metric and some mowers are a mix of both. If your mower is European or Asian it will be metric sizes.
The trouble is you can get an imperial wrench to almost fit a metric bolt, but it’s loose and will slip, which rounds the bolt head. Typical bolt sizes for mower blade bolts are Imperial 1/2″, 5/8″, 3/4″ and Metric sizes 13mm, 14mm, 15mm, 16mm, and 17mm.
Imperial or Metric, be sure your tools are a good fit.
Tools You’ll Need
Impact power tools are designed for this exact job. They cause a hammering action which helps reduce the bolt thread friction and breaks any corrosion loose. So if you have an air or battery impact tool, you going to feel like a superhero when that bolt just walks out.
Basic tools needed assuming you don’t have an impact tool: wire brush, wd40, ratchet sockets, selection of wrenches.
Other tools you’ll need if things don’t go exactly to plan: breaker bar, hammer chisel, butane torch, and if everything goes to crap, a Mig welder. In my workshop, I use an air impact tool, if you haven’t got one or can’t borrow I have other solutions for you.
But the tool I am least likely to be without is an impact tool, it just makes life really easy and saves so much time. The coolest thing about the latest generation impact tools is their mobility, cordless now packs the power of an air tool. Great for around the home and for flat wheel emergency, use it to run the jack-up and take the nuts off.
Although I still use air in the workshop, I bought a 20v Ingersoll Rand cordless for mobile repairs, I know they ain’t cheap but you won’t ever need to buy another.
If you do buy an impact tool, you’ll need to buy impact sockets too. Sure you can use regular sockets, but you run the risk of them shattering. Anyway, you’ll find all these tools on the “Small engine repair tools page”.
Tool Up – Most stuck bolts won’t need all these tools, but some do.
Removing The Bolt
Removing a stuck bolt involves trying different solutions until you ring the bell. In the first attempts, we’ll try the simple stuff and if that doesn’t move it, I have lots more ideas.
Before we start any work on our mower we need to make it safe. Pull the plug wire off and set it away from the plug. Turn your gas off if you have a gas tap, if you don’t know where your gas tap is check out “Gas tap location”.
WD40 is my favorite tool, it solves lots of problems, I also like a product called nut buster, it’s formulated for dissolving rust. Try spraying the bolt liberally above and below the blade, and allow it time to work into the threads.
Disable Mower – For safety, let’s remove the plug wire and turn off the gas.
Turn the mower over with the carburetor side facing up, stops gas leaking on the floor. (see tilting mower over)
Wire Brush to remove any rust. Wd40 Spray front and rear of the bolt and give it some time to soak in.
Impact Tool – By far the preferred way to remove a bolt. An Impact gun hammers the bolt as well as twists it, this loosens the corrosion between the threads.
An impact tool will remove the bolt in seconds and you won’t need to lock the blade. But if the bolt head is rounded, the impact tool is of no use. You’ll need a different solution.
Check out the Amazon link, some of these impact wrench surprised me.
Lock Blade – If you are not using an impact tool we’ll need to use a piece of timber to lock the blade against the body. Longer timber is better than shorter. Cut a length to suit.
Good Fit – Select a socket (6 points preferably) and check the fit. Turn the ratchet left to loosen. Using a breaker bar, or if you don’t have to improvise with your ratchet and some pipe.
Pushing down on the pipe will give you the extra power you need to break it loose. Just be sure the socket is a good fit, and it stays on the bolt head when you’re applying force.
Wrench Leverage – Turn the Wrench left to loosen. If you don’t have a ratchet and breaker bar, try 2 interlocked wrench’s for extra leverage, or use a hammer to shock the bolt.
If it still won’t budge, try tightening it slightly, this often helps, odd I know!
Striking – Try striking two hammers sharply (wear eye protection) while one is placed against the bolt head, this can help break loose any corrosion on the threads. If the head of the bolt is rounded, move on to the next solution.
Rounded Bolt – If your bolt head is rounded, try a vice grip. Get it as tight as you can, and try hitting it to the left sharply with a hammer.
Lawn Tractor Mower Deck Won’t Engage. FIX PTO Clutch Problem. MUST SEE VIDEO!
Not all vice grips are the same, for this application you’ll need a flat jawed set. Check out this post on Vice-grips tools.
Chisel – This method is pretty effective, but you’ll need a new bolt, sharp metal working chisel, and a heavy hammer. With the chisel and hammer, take a sideways and downward aim at the bolt, we’re attempting to loosen it by turning it left. This will require good aim, so now’s a good time for those gloves.
Heat – Ordinarily I’ll tell you to get some heat on the bolt, the reason I haven’t introduced it earlier is that it comes with the risk of damaging the crankshaft nylon seal, which would cause the engine to leak oil.
The risk of this is fairly small, once you direct the flame and only use a small amount. We’re not going to redden the bolt, just going to heat it up.
Maybe 2 minutes with a butane torch directed at the bolt. You can now try heat with any combination of the above methods. Heat is very successful at helping move stuck bolts.
Welding – This method will obviously require a welder, when I get a really stubborn bolt with a rounded head, I take a new bolt and weld it to it. This gives me a not-so-pretty but clean bolt head to work with.
This solution has never failed me yet. You’ll need to replace the bolt. Blade bolts have a fine thread, they are a specialized bolt, getting one in the hardware store isn’t advisable.
Torque – Finally, you’ll have to move your timber to lock the blade in the other direction and torque your new bolt to spec.
Check out this post to see why it’s important to torque your blade bolt.
The spindle turns when removing the blades? The easiest way to prevent the blade from turning while loosening the blade bolt is to use a large block of wood to lock the blade against the mowing deck.
Lawnmower blade bolt direction? Turn the mower on its side, carburetor side up, turn the blade bolt to the left (anticlockwise) to loosen.
Hey, I’m John, and I’m a Red Seal Qualified Service Technician with over twenty-five years experience.
Common Problem FIXED! Hard to Push Riding Lawnmower. BRAKES LOCKED UP. Neutral Problems
I’ve worked on all types of mechanical equipment, from cars to grass machinery, and this site is where I share fluff-free hacks, tips, and insider know-how.
And the best part. it’s free!
Lawn Mower Pull Cord Won’t Retract
You’ve just finished cutting the grass with your trusty lawnmower when you walk over to start it up again and pull on the starter cord, but nothing happens. What should you do?
When your lawn mower pull cord won’t retract, it may be due to a broken or jammed assembly, rusted ball bearings, and a damaged starter clutch or recoil mechanism. Easy fixes include replacing the broken, rusted, or damaged parts. Also, lubricating the moving parts may help solve these problems.
Read on to learn more about the problems that may cause your lawn mower’s pull cord to not retract, and easy fixes that may help.
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The Pull Cord Assembly Is Broken or Jammed
If the lawnmower pull cord is broken or jammed, it will not retract. In general, the pull cord assembly may do the following:
- Break or get jammed due to a bent or broken pulley.
- Have a bent or broken cord.
- A slipped knot in the cord jams when the end comes through the hole in the housing.
- Rust/corrosion from exposure to weather affecting metal components.
Here are some tell-tale signs of a broken or jammed pull cord assembly:
- The pull cord is broken, or the pull cord is hanging loose but is not attached to any part of the mower.
- The pulley does not rotate when you pull on the starter cord.
- The starter grip rotates with the pulley, but no cord moves through it because there’s an obstruction in the housing, such as something blocking the passage of the cord.
- The engine starts fine but stops running as soon as you release the handle or stop pulling on the cord.
How To Fix
To fix a broken pull cord, replace it with another similar-sized sturdy rope or leather cord. Make sure to knot it securely at both ends. If the pulley is bent or otherwise damaged, replace it. Have a professional repair any stripped teeth on the engine flywheel or replace it if necessary.
You could also disassemble the starter housing as far as needed to access what needs to be repaired or replaced.
As for corroded ball bearings, spray them with lubricating oil (WD-40 works well) and then work the pull cord until they loosen up again; otherwise, replace them entirely.
The Ball Bearings Have Rusted
If the ball bearings have rusted due to exposure to weather affecting metal components, the lawnmower pull cord won’t retract because the ball bearings in the starter clutch are frozen or rusted.
Here are five signs that your lawn mower’s ball bearings are rusted:
- The starter cord doesn’t fully retract when you release it.
- The starter cord pulls out slowly and reluctantly, even when you’re just trying to roll the mower around in place.
- There’s a noticeable clicking or popping sound every time you pull the starter cord and try to start the engine.
- You can hear and feel a gritty rustling noise coming from inside the lawn mower housing when you try to retract the starter cord by hand.
- When you pull up on the starter cord, it barely moves at all. Or if it does move, then it moves only slightly but requires great effort.
How To Fix
For starters, try spraying them with lubricating oil, such as this highly effective, easy-to-apply, and moisture-displacing WD-40 Multi-Use Product with Smart STRAW (link to Amazon), and then working the pull cord until they free up again.
Also, you can try cleaning the rust/corrosion off of the ball bearings with steel wool or sandpaper to give them a fresh start. If these solutions don’t work, replace them entirely. As for the started clutch–check it for damage and replace it as necessary.
Additionally, ensure you always clean your mower to keep it in the best shape. Here’s a video that may help:
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Why Engine Dies When PTO Is Engaged? Reasons And Solutions Explained
PTOs are used to transfer power from the engine to a tool or attachment. When the engine is not running at its optimal level, it can cause the mower to have problems when the PTO is engaged.
If you have a mower that is dying when the PTO (Power Take-Off) is engaged, it indicates a problem with the engine. The reasons include – a worn-out spark plug, a clogged air filter, a blocked fuel line, or even a faulty PTO switch.
This article will discuss more reasons in details and how to fix each issue when the engine dies when PTO is engaged. So tag along till the end!
What Causes A Mower Engine Dies When Pto Is Engaged Engaged? (Fixes Added)
There can be several reasons why a lawn mower engine may die when the PTO (Power Take-Off) is engaged. These are discussed below:
Mower Blades Engagement Issue
The most common cause is that the mower blades are not properly engaged. This means that the blades are not securely connected to the PTO shaft. This causes the engine not receive necessary power to keep running.
Fix: Blade Adjustments
Make sure the blade you are using in the mower is appropriate for the engine. Make sure it has proper connection with the engine.
Here is a table containing proper mower blade size for engine:
|Engine Capacity (cc)||Blade Length (in)|
|50 – 75 cc||18 – 20 inches|
|76 – 100 cc||20 – 22 inches|
|100 – 125 cc||22 – 24 inches|
|126 – 150 cc||24 – 26 inches|
|151 – 175 cc||26 – 28 inches|
|176 – 200 cc||28 – 30 inches|
|201 – 225 cc||30 – 32 inches|
|226 – 250 cc||32 – 34 inches|
|251 – 275 cc||34 – 36 inches|
|276 – 300 cc||36 – 38 inches|
It’s possible that the seat switch is bad, or that there’s a loose plug or a bad wire.
Fix: Replace Seat Safety Switch
The seat safety switch can be damaged or stuck. Replace the switch if cleaning does not get rid of the stuck switch.
Clogged Air/Fuel Filter
A dirty air or fuel filter can restrict air or fuel flow to the engine respectively. This might cause the engine to die when the PTO is engaged.
Fix: Replace Dirty Filters and Lines
Replace the dirty fuel filter and air filter. Also replace any damaged fuel line. Clean the carbon buildup in any fuel line.
Bad PTO Clutch and Worn Out PTO Belt
The PTO clutch can wear out or become damaged over time. This may cause it to fail to engage properly. As a result, the engine to stalls when the PTO is engaged.
Besides, a worn-out or damaged PTO belt can cause the engine to die when the PTO is engaged. The belt can become worn and stretch over time. This results in a loose connection between the engine and the blades.
Fix: Replace Bad PTO Components
When the problem occurs, here are the PTO components to troubleshoot:
- Inspect the PTO clutch cable to ensure that it is in good condition and connected properly. If it is worn out or loose, then replace it.
- Inspect the PTO clutch to make sure it is not broken or damaged. If it needs to be replaced, then do so.
- Clean the PTO clutch to make sure it is free of dirt and debris. This will help ensure that it is engaging properly.
- Inspect the PTO engagement lever to make sure it is working properly. If it is not, then replace it.
- Inspect the PTO switchto make sure it is working properly. If it is not, then replace it.
Problem with the Battery
Additionally, if the battery is low or the charging system is faulty, the PTO clutch will stall the engine.
Check the battery wiring, charge and if needed, replace with a new battery.
Other causes of engine failure when the PTO is engaged include a faulty spark plug, a dirty carburetor, a clogged fuel line or a PTO switch in ‘on’ position.
How to Diagnose a Mower Engine That Dies When the PTO Is Engaged
It can be confusing as to how to get started with troubleshooting when the mower engine dies when PTO is engaged. However, look at the step by step process below:
Check the spark plug. If the spark plug is wet or fouled, replace it and try to restart the engine. Make sure the spark plug has secured connection.
Check the air filter. If the air filter is clogged or dirty, replace it.
Check the fuel filter. If the fuel filter is plugged or dirty, replace it and check the fuel line for any blockages.
Check the carburetor. Make sure it is properly adjusted and that all of the screws are tight. Check for any signs of dirt or debris.
Check the ignition system. Make sure the spark plug wires are connected properly, and that the ignition switch is working properly.
Check the PTO switch. Make sure the switch isn’t stuck in the “on” position. If necessary, replace the switch.
Check the PTO clutch. Make sure it is functioning properly and that all the connections are tight.
Note: If these steps do not resolve the problem, it is likely that the engine itself is malfunctioning and needs to be serviced or replaced.
Easy Fixes for a Mower Engine Dying
Not just when PTO is engaged, but a mower engine dying is a common complaint. In addition to the discussed solutions, the following can fix the mower engine dying:
- Check the fuel – Make sure the fuel is fresh and has the correct mix of oil and gasoline.
- Change the spark plug – A worn spark plug can cause the engine to misfire and die.
- Clean the carburetor – A clogged carburetor can prevent the engine from getting enough fuel, causing it to die.
- Adjust the idle speed – An incorrect idle speed can cause the engine to die when it is not running at full throttle.
- Check the compression – Low compression can cause the engine to die.
- Check the governor – An incorrectly set governor can cause the engine to die.
- Check for vacuum leaks – Vacuum leaks can cause the engine to die.
Going over these things makes sure you don’t leave any stone unturned to fix your dying engine. But if the problem persists, a professional intervention becomes a must.
Maintaining a beautiful lawn can be a daunting task, especially if you lack the appropriate know-how and tools to handle the challenges that may crop up. Fortunately, LawnAsk is here to offer you an all-encompassing resource that covers everything you need to know about lawn care.