How To Fix A Lawnmower: 5 Common Problems. Lawn mower clutch problems
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.
How to Fix CRAFTSMAN Riding Lawn Mower Problems
CRAFTSMAN-riding gasoline-powered lawnmowers are fantastic for cutting larger expanses of grass, such as those found in golf courses or parks. Being able to drive the mower is much more fun and requires far less physical exertion than pushing a mower up and down in the blazing sun.
CRAFTSMAN Riding Lawn Mowers offer many advantages but do occasionally develop problems:
Engine won’t start
Blades won’t engage
Runs for a bit, then dies
Won’t cut lawn evenly
Won’t drive forward
Doesn’t steer correctly
Exhaust billows smoke
And more …
Engine Won’t Start
We all know the disappointment when you’re all “dressed up” and ready to tackle the first lawn-cutting exercise of the season, only to find that your trusty CRAFTSMAN riding mower won’t start.
The CRAFTSMAN riding mower is, of course, fitted with a gas engine which means several problems could be causing the engine not to start. The below covers the common reasons why the engine doesn’t start.
Solution 1: Drain and Replace Old Gas
Check that the gas tank contains fuel, especially if the mower has been standing for an extended period. Gasoline degrades over time and evaporates.
Old gas should be drained from the system and replaced with new to eliminate this problem.
Solution 2: Replace the Fuel Filter
Following the gas line from the gas fuel tank to the carburetor will lead you to the fuel filter. The filter may be dirty, restricting or preventing fuel from reaching the carburetor so the mower won’t start.
If the fuel filter is visibly dirty inside, replace the fuel filter to ensure the gasoline can pass through the filter.
Solution 3: Ensure All Safety Cutoff Switches Are Engaged
CRAFTSMAN riding mowers have two safety switches that ensure the mover won’t start accidentally. One switch is under the driver’s seat, and the foot brake controls the other.
Their design is such that the driver must be seated on the seat, and the brake must be depressed to disengage the safety switches for the mower to start. Standing next to the mower while trying to start the engine will not work.
Solution 4:Charge the Battery
All CRAFTSMAN riding mowers have a battery located under the driver’s seat to turn and start the engine. When turning the ignition key and the engine turns very slowly but won’t start, the battery is most likely discharged.
Turning on the ignition and hearing a clicking sound without the engine turning is a sure sign that the battery is drained and needs to be charged.
In both scenarios, the battery requires charging, or if the problem persists, the battery may need replacement.
Solution 5: Clean or Replace the Solenoid
The carburetor fuel solenoid is attached to the base of the carburetor. The carburetor controls the fuel and air mixture required for the engine to run. The solenoid is an electrically operated fuel supply and shut-off valve. When the valve doesn’t work, it prevents fuel from entering the carburetor.
Diagnosing if the solenoid is faulty is quickly done by getting an ear down close to the solenoid. A click sound will be heard when the key is turned on and off as the solenoid retracts and releases. If no sound is heard, the solenoid is likely faulty and requires replacement, or the mower won’t work.
The solenoid will need to be removed by unscrewing it with a spanner of the right size and cleaned or replaced if the cleaning doesn’t work.
Solution 6: Replace the Filter
The air filter is next to the carburetor and filters the air fed into the carb. When the air filter is filthy, it may get clogged up by dust particles. The clogged-up filter will prevent air from reaching the carburetor and the engine from starting.
The solution is to replace the filter with a new one.
Solution 7: Replace the Spark Plug
The spark plug performs the critical task of igniting the fuel in the cylinder head while the engine is running. The spark plug is constantly exposed to burning gas and oil residue; therefore, the spark plug can quickly become dirty.
Removing the spark plug is a simple exercise using a spark plug spanner. A dirty spark plug can be cleaned using a wire brush but will eventually need to be replaced. Instead, replace the spark plug to be sure it’s working well.
Blades Won’t Engage
Your CRAFTSMAN riding mower is running, you’ve reached the area that needs mowing, but now the blades won’t engage. What could be wrong?
We’ve found five possible causes for the blades not engaging with CRAFTSMAN riding mowers. These problems may differ depending on if your mower has a manual lever clutch or an electronic PTO clutch.
Solution 1: Replace the Electric PTO Clutch
Faulty PTO clutch. When power is supplied to the clutch, the clutch engages and turns the mower’s blades via the drive belt. When the PTO clutch doesn’t engage, the internal mechanism has failed.
The PTO clutch is not a repairable part as it’s a sealed unit, so it needs to be replaced.
Solution 2: Remove and Test Take-off Switch
The second reason the blades won’t engage on the electrically operated unit is a faulty power take-off switch. This switch is located on the dashboard of the mower and is usually yellow. Pulling the switch engages the blades, while pressing the switch disengages the blades.
Removing the switch and testing it for continuity using a multi-meter is the best to determine if the switch won’t work. If faulty, the switch would need to be replaced as you can’t repair it.
Solution 3: Replace Drive Belt
Before we deal with the manual clutch mowers, one common item between the electric clutch and manual version mowers is the drive belt.
The drive belt is located underneath the mower and connects the crankshaft to the mower blades via the clutch assembly.
The drive belt is a high-quality V belt, similar to those used in model car engines. When this belt becomes excessively worn or is damaged or cut, it can no longer drive the mower’s blades, which won’t work.
The drive belt must be replaced when damaged or worn out.
Solution 4: Replace Lever Mechanism Unit
CRAFTSMAN riding mowers fitted with a manual clutch can suffer the following failures over time that prevent the mower’s blades from engaging.
The clutch engages and disengages the blades on the manually operated version. The clutch is operated by pulling down a lever on the right of the dashboard. A cable connects the lever mechanism to the clutch located under the mower.
The lever mechanism in the dashboard can fail over time, making it impossible to retract the cable connected to the clutch.
A failed lever mechanism will require the replacement of the unit.
Solution 5: Replace Broken Clutch Cable
Broken manual clutch cable or spring: The cable, as mentioned earlier, connects the lever mechanism, and the clutch, along with its tensioner spring, is wearing parts, so it can fail with excessive use and eventually won’t work.
A broken or severely worn clutch cable and its accompanying tensioner spring must be replaced should they fail.
Runs for a Bit, Then Dies, Won’t Work
The CRAFTSMAN riding mower is reliable and generally doesn’t cause problems. Occasionally, you may find that your mower starts up and then dies. When you crank it, it starts, only to turn off again.
Solution
Briggs and Stratton’s engines used in CRAFTSMAN mowers are four-stroke engines, so they use unmixed fuel (no two-stroke oil required). They generally run very clean and shouldn’t develop any carburetor blockages.
Fuel starvation is the most likely cause of the engine starting and then stopping shortly after.
Assuming the fuel tank is sufficiently filled and contains fresh fuel. The motor dies because the fuel entering the carburetor flows in slower than the outflow of fuel into the engine; effectively, the carburetor runs dry, which causes the problem.
The cause is a blocked fuel line or clogged fuel filter. 10% Ethanol fuel is tough on rubber fuel hose and causes the fuel line to degrade internally. This degradation blocks or severely reduces fuel flow from the tank to the engine.
Replacing the fuel line and filter will restore the fuel flow to the motor and prevent the engine from turning off when you least need the problem.
Won’t Cut Lawn Evenly
Cutting a large section of lawn only to realize that you’ve cut a series of steps into the lawn’s surface can be disappointing. How does this happen?
Solution
An uneven cut results from the mower deck (cutting blades) not being set to the correct height, or your mower may have a deflated tire causing the problem.
A mower-cutting deck rides on a series of linkages. They allow the deck to be adjusted up and down to adjust the cutting depth.
An underinflated or flat tire can play havoc with the angle of the cutting blades. If the blades are not level with the ground and cut deeper on one side of the mower, it will result in an uneven cut. So make sure all the tires are inflated to the correct pressure.
Cutting deck adjustment is made through two adjustment bolts. One adjusts the height seen from the left and right of the deck, and the other changes the front and rear deck height. It’s quick and easy! We’ve attached the below YouTube video, which details how the adjustments are performed.
Won’t Drive Forward
Like so many other mechanical devices, excessive use of a CRAFTSMAN riding mower will eventually take its toll. Occasionally something may go wrong, preventing it from driving. The gear lever is one of the items on a mower that sees a lot of use as it’s constantly shifted between drive, neutral, and reverse.
Solution
The linkage joining the gear selection lever and the actual gearbox may go out of alignment or get clogged up with dirt, preventing the gear levers from traveling the entire distance to engage or disengage a gear. Of course, the gearbox could be faulty, but this is unlikely as they’re robustly built.
Following the gear level selector down below the right fender of the mower will reveal the linkages that would need adjustment when gear selection becomes difficult.
Given that the linkages vary from model to model, it may be necessary to enlist a professional. Alternatively, some trial-and-error adjustments may do the trick.
A build-up of dirt inside the linkages is a real problem. The underside of the mower is exposed to a lot of dust generated by the spinning blades.
Carefully removing the various parts of the gear selection linkage will reveal dirt that prevents the levers from shifting their entire length of travel, preventing the shifter from working. Removing the dirt will enable the gears to be selected and allow the mover to drive.
Doesn’t Steer Correctly
The CRAFTSMAN riding mower follows a traditional tractor design, having two driving wheels at the rear and two front wheels that provide steering by turning left and right. The driver operates a steering wheel precisely like you would when steering a vehicle.
Over time the steering mechanism of the CRAFTSMAN riding mower is prone to developing a problem with turning to the left but normally turns to the right. Fortunately, this is a pretty simple fix.
Solution
The CRAFTSMAN steering mechanism is pretty basic, consisting of a steering column housing a gear that connects to a gear plate. The gear plate connects the left and right front wheels via a metal rod or linkage. The gear plate rotates as you turn the steering, changing the wheels’ direction.
The steering column’s base gear plate is slotted to limit the wheel’s rotation to either side. Over time the slot located in the gear plate becomes clogged with dirt which is compressed into a solid mass inside the slot or cut out, causing left turns not to work.
The dirt build-up inside the slot limits the gear plate’s movement, limiting the wheels’ ability to turn. The plate design seems to create the problem when turning left only.
The gear plate needs to be removed to get the wheel turning again, which is more straightforward than it may sound. The dirt and grime build-up must be removed from the slot in the gear plate, and the area housing the plate must be cleaned. Once the dirt is removed, the steering mechanism will function.
Exhaust Billows Smoke
Even a great engine such as the ones used in the CRAFTSMAN riding mowers can develop a problem where white smoke starts billowing from the mower’s exhaust. The problem can become so bad that the engine won’t work.
Solution
Worn piston rings can cause the mower’s engine to billow smoke, but this tends to happen slowly over time. If a perfectly good running engine suddenly starts billowing smoke, the cause is likely a blown head gasket.
The head gasket seals the space between the cylinder head, which houses the valves, and the part of the engine housing the piston. When smoke starts billowing from the exhaust, it’s a sign that oil and even water are entering the combustion chamber, where the oil ignites and starts smoking.
Replacing the cylinder head is a task best left to a mechanic as additional damage, such as a cracked head, may have developed and would require identification and repair.
Vibrates a Lot When Mowing
Vibrations are common amongst riding mowers as they bump and grind their way. Excessive or new vibration is not good, meaning something has a problem.
Numerous problems can cause vibrations, but the most common is a blade or blades that have become unbalanced or, in older machines, a mandrel that’s gone faulty. The mandrel contains a shaft supported by bearings. The mandrel houses the blade on one end and a pulley around which the drive belt runs.
Numerous problems can cause vibrations, but the most common is a blade or blades that have become unbalanced or, in older machines, a mandrel that’s gone faulty. The mandrel contains a shaft supported by bearings. The mandrel houses the blade on one end and a pulley around which the drive belt runs.
Solution 1: Replace Worn or Damaged Blade
CRAFTSMAN blades are made of high-quality hardened steel, which lasts a long time. Blades take the brunt of the force when cutting grass; although one tries to avoid it, they strike a rock occasionally. The impact can bend or even break a blade piece, which can cause vibration.
The solution is to replace the damaged blade with a new blade. A replacement will stop the blade from vibrating.
Solution 2: Replace Worn or Damaged Mandrel
A worn or damaged mandrel can cause the mower to vibrate. Although mandrels are a sturdy kit, they can eventually wear and fail, causing vibrations.
The mandrel needs to be replaced to fix this vibration, per the YouTube video below.
Lawn Mower Repair The How to Guide to Fixing It Yourself
Despite care and maintenance, machines can suddenly develop a problem that needs to be fixed. Your lawn mower is a hard-working machine and sometimes that hard work results in damage that needs to be undone.
Knowing how to do minor repairs on your lawn equipment yourself can save you some time and money. With that in mind, we’ve created this guide on lawn mower repairs for you. To get your lawn mower serviced by experts, come to one of our John Deere dealership locations throughout Central and Southern Florida.
Starting Problems
If your mower isn’t starting or starts and stops, then you probably have a clogged carburetor. The most common way to end up with a clogged carburetor is to leave fuel in the mower when it’s not in use for a long time. The liquid parts of the fuel evaporate, leaving behind a sticky, gooey mess that clogs your carburetor and prevents the engine from starting. Use a carburetor cleaner to clean it thoroughly.
Another culprit behind starting issues in lawn equipment is a damaged spark plug. Check to see if it has any signs of wear or damage. Use a spark plug tester to check if it’s defective; if you don’t see a strong spark between the tester’s terminals then it’s time to replace the spark plug. If there is carbon buildup in the electrode, an electrode is damaged, or the porcelain insulator is cracked, replace the spark plug.
Battery Problems
If your lawn mower battery keeps dying on you, one or more cells in it may have died. Use a charger to charge the battery. If it doesn’t hold the charge, you need to get a new battery. Sometimes, though, it may be that other components are at fault, not your battery. Use a multimeter to check that the charger is giving proper voltage output. A multimeter will also let you check the alternator which recharges the battery and gives voltage to your mower when in use.
Blade Problems
If the blades on your lawn mower do not engage, you could have a problem with the PTO switch. A multimeter will let you check if the switch is damaged and needs to be replaced. If your switch is fine, the problem may lie in your PTO clutch. This clutch manually disconnects the engine from the blades. When the clutch solenoid is powered, it uses the drive belt to move the rotation of the mower blades. If there is anything wrong with the PTO clutch, it will need to be replaced as it can’t be repaired.
Gas Leak Problems
One common lawn mower repair involves gas leaks. To determine what you have to fix, you need to check where the leak is happening. If the bottom of the carburetor is leaking fuel, the carburetor bowl gasket might be missing or dried out. Replace this gasket. Another reason behind a gas leak could be the float needle not shutting off fuel. This needle opens and closes the float valve to allow fuel into the float bowl. If it’s damaged, the fuel will fill the carburetor until it overflows. Replace it if it’s damaged.
If neither of the above is the problem, examine the fuel shut-off valve. The fuel lines should be tightly affixed to the valve and shouldn’t have any cracks, tears or holes in them. If a fuel shut-off line or the fuel shut-off valve is leaking, replace it immediately. Do not attempt to patch or cut and rejoin a fuel line.
Overheating Problems
Overheating is another common issue that occurs in lawn mowers but it is easily avoidable with a little care. Your mower has an air-cooled engine with cooling fins fixed into the engine’s cylinder head and short block. These fins keep the engine cool while your mower is busy at work. Sometimes bits of grass, leaves, and debris can clog these fins so you need to clean your mower at proper intervals or after heavy use to ensure this doesn’t happen to your machine.
Smoking Problems
It can be scary to see your lawn mower start to expel thick black smoke but what this indicates is that your carburetor is ‘running rich’, i.e. it is getting too much fuel. Check to see if the carburetor float is jammed in the open position and fix it if it is. Another reason behind black smoke is the carburetor choke valve being closed. It needs to be open once the engine is running or the engine won’t get enough air to create the right fuel-air mix.
We hope this list helps you identify and perform common lawn mower repairs. If you can’t really tell what’s wrong with your mower or want to purchase quality lawn equipment, come to Everglades Equipment Group at one of our 17 locations in Florida. We’re always happy to whip old machines into good shape and help people choose the right machines for their needs. We are proud to serve the areas of Central and South Florida!
Easy Repair of a John Deere X304 Clutch
It’s amazing how time flies. Although it has been about 13 years since I bought the John Deere X304 lawn tractor for the ranch, it seems like yesterday. I still think of it as “the new tractor.” So it’s always a surprise when something needs repair. I use this machine for all kinds of things, from mowing to towing, and recently it developed a screaming sound near the front.
I have a tendency to imagine the worst, and immediately wondered if there was a bad bearing in the engine. A little sleuthing turned up a much less scary problem — the PTO/mower clutch seemed to be the source of the noise. With the drive belt disconnected, the noise went away, and I was able to continue with the towing I needed that day without much time lost. A problem for another day.
YouTube shows the way
I checked with the dealer, and a new PTO clutch was close to 300 installed. I would also have to get it there. Later on, I started looking around the InterWebs for info about this problem, and YouTube provided several videos. Try searching for “john deere x304 mower clutch.”
Apparently the clutch was replaceable without too much difficulty. Apart from disconnecting the drive belt and electric clutch cable, two bolts held the clutch in place; one to the tractor chassis, and the other on the engine shaft.
Amazon has the parts
Now what about the part? I could buy it direct from John Deere, but was pretty sure it would be a premium price. Back to my old standby: Amazon. I’m still amazed at what all they carry, and sure ’nuff, that they had a direct replacement part for 149. One YouTube video mentioned a little trouble removing the clutch from the engine shaft and recommended Kano Aerokroil to penetrate and loosen the parts. Although a little expensive at 20 a can, it seemed like cheap insurance. I’m always interested in new strategies for removing corroded parts.
An opportunity to buy a new tool
I had considered buying a mower lift every season for the last several, but the price was always just a little more than I wanted to pay. This was the moment since I would end up with a new tool and still come in under the dealer installation price. The Pro Lift T-5305 with Hydraulic Jack was on sale, and big enough to lift the fairly heavy X304. It would make it much easier and safer to work on the bottom of the tractor. A few days later, everything had arrived and I was ready to go.
Getting the mower up in the air
The Pro Lift box was damaged in shipment and a couple of the metric bolts needed to attach the wheel baskets were missing, but I was able to find replacements in my horde. It was easy to assemble. I started the repair by removing the mower deck. It’s easy on these models with the removal of four large cotter pins and then detaching the lift mechanism pins.
As I’d hoped, the lift easily raised the front end of the mower, and had safety mechanisms that would prevent the lift from descending accidentally. I now had easy access to the faulty clutch.
Removing the old mower clutch
Using an Impact Driver on the Engine Bolt
The bolt connecting the clutch to the chassis was easy to remove but the bolt on the engine shaft required a little persuasion. A pneumatic impact wrench made it easy. As the video had predicted, removing the clutch from the engine was a little tricky, probably because it is connected by a keyed shaft. The Aerokroil wasn’t needed though and after a few taps with a machinist’s hammer to break it loose, the clutch slid right off.
Disconnecting the wires turned out to be the hardest part because they travel through the chassis and connect to the engine above. The plug wouldn’t fit through the available hole. I simply cut the wires on the old part.
A new clutch installed in minutes
The new clutch fit perfectly, and was installed in a couple of minutes. I routed the wires to a different hole (that the plug would fit through) and got it connected. After lowering the mower from the lift, I replaced the mower deck, stretched the belt over the new clutch pulley and started the engine. No more screaming. Pulling the mower switch out, the clutch engaged and the mower was running again. Another successful repair and the satisfaction of doing it myself. Also, I avoided trailering the mower to the dealer and I had a new lift to boot!