14 Common Cub Cadet Mower Problems & Solutions

Owning a Cub Cadet lawn mower does not come without its problems. Even though Cub Cadet is a major player in the lawn care industry providing great products for your lawn needs, their lawn mowers will eventually fail.

Whenever a product includes mechanical parts, it is bound to fail even if you take good care of it. I have put together this guide to help you identify a problem and solution for your Cub Cadet push mower, riding mower, or zero turn.

Many of these problems have simple solutions that you are able to do at home while some should be addressed by an experienced lawn mower or small engine mechanic.

I have listed causes with a quick solution. For more information on any issue, just follow the links provided.

Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

Troubleshooting Cub Cadet Mower Problems

Won’t Start

A mower may not start because of fuel or air restrictions not allowing the engine to get the fuel and air required to run. Your starting problem may also be due to a bad spark plug or a failed electrical component.

Detailed information can be found at:
Cub Cadet Mower Won’t Start

Cause	Reason for Problem	Solution
No gas in the fuel tank	Fuel tank is empty	Fill with fresh fuel
Bad or old fuel	Fuel breaks down overtime making your fuel less efficient and prone to clogging the fuel system	Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system. Use the right fuel.
Faulty or clogged fuel cap	The vent in the cap can get clogged causing your tank to form a vacuum restricting fuel flow	Use a thin piece of wire to try to clear the clogged vent. Replace the cap if needed.
Bad spark plug	Excessively dirty or broken spark plug; bad connection; not gapped correctly	Replace with a new spark plug, secure connections, and ensure it is gapped to manufacturer specifications
Plugged air filter	Dirt and grass can plug the air filter preventing airflow	Remove the filter and clean it. Replace the filter if it is in bad condition.
Plugged fuel filter	A dirty fuel filter will restrict fuel flow	Replace the fuel filter
Bad fuel pump	A failed or leaking fuel pump will no longer create the pressure needed to pump fuel	Replace the fuel pump
Blocked fuel lines	Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel	Use a carb cleaner and compressed air to clear the clog out of the fuel line. Replace the line if necessary.
Dirty carburetor	The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow	Clean all of the components of the carburetor. Replace if needed.
Bad battery or loose & dirty terminals	A dead battery, loose cables, or corroded terminals can cause starting problems	Charge your battery and replace it if it won’t hold a charge. Make sure your cables are tight and clean the corrosion from terminals.
Bad safety switch	Safety switches are a safety measure that exists to prevent your mower from starting in certain situations. When a switch fails, your mower may not start.	Test and replace faulty safety switch.
Bad ignition switch	Your mower will not start when either the ignition switch.	Test and replace a bad switch.
Broken recoil	A pull start mower may have a damaged or broken recoil preventing the recoil to initiate starting your engine	Check the recoil to see if it can be restrung or if broken parts, like the pulley, can be replaced. Replace the recoil assembly if needed.

Loses Power and Dies

Lawn mowers can experience loss of power when the fuel or air systems are compromised affecting your mower’s ability to run. This can include bad fuel, a bad air filter, a dirty carburetor, and clogged fuel lines.

Detailed information can be found at:
Cub Cadet Starts Then Dies While Mowing

Cause	Reason for Problem	Solution
Bad fuel	Fuel breaks down overtime making your fuel less efficient and prone to clogging the fuel system and engine damage	Drain the fuel tank and fill it with fresh fuel. Use a fuel additive like Sea Foam to stabilize the fuel and assist with cleaning the fuel system
Plugged air filter	Dirt and grass can plug the air filter preventing airflow	Remove the filter and clean it. Replace the filter if it is in bad condition.
Dirty or broken cooling fins	Cooling fins get packed with dirt, oil, and grass not allowing air to effectively cool the engine block	Replace broken fins and clean the cooling fins.
Clogged fuel lines	Bad fuel deposits and dirt can build up and clog the fuel lines preventing the engine from getting the required fuel.	Use a carb cleaner and compressed air to clear the clog out of the fuel line
Bad Fuel Pump	The fuel pump is used to move gas to the carburetor when the carburetor sits higher than the fuel tank.	Replace a bad fuel pump.
Dirty carburetor	The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow	Clean all of the components making up the carburetor. Replace if needed.
Bad Gas Cap	When the gas cap won’t allow air to pass through it to vent the fuel tank, a vacuum forms restricting fuel flow.	Replace a bad gas cap.
Wrong Engine Oil Level	Too little engine oil can cause increased friction and heat in the crankcase. Too much oil will build pressure in the crankcase.	Correct the engine oil level. Contact an engine mechanic for assistance if this does not solve the problem. You may have engine damage.
Plugged Mower Deck	A deck packed with grass clippings and debris can put an extra load on the engine and may cause it to die.	Scrape the mower deck regularly to keep it clean. Avoid cutting wet grass as it is more prone to sticking to the deck.
Bad Ignition Coil	The coil can separate and short out when hot keeping voltage from getting to the spark plug.	Replace an ignition coil that has a break in continuity.
Dirty Spark Plug	A dirty spark plug may cause intermittent spark.	Clean the spark plug or replace it when it is extremely dirty or worn.

Engine is Smoking

A mower will smoke when oil gets into the cylinder and begins to burn off; components begin to burn due to increased friction from low oil capacity; and additional engine failures happen internally including the piston ring, valve train, and gaskets.

Detailed information can be found at:
Why Your Cub Cadet Lawn Mower is Smoking

Cause	Reason for Problem	Solution
Plugged air filter	Dirt and grass can plug the air filter preventing airflow	Remove the filter and clean it. Replace the filter if it is in bad condition.
Too much oil in the crankcase	Excessive oil can cause pressure to build in the engine allowing oil to get into the cylinder through the valve train	Drain a little engine oil until it is at the manufacturer’s recommended oil level.
Low engine oil level	Lack of oil can increase friction in your engine causing extreme heat in the engine	Bring to a small engine repair shop to inspect engine damage. You can try adding oil, but it is often too late to fix your engine problem.
Internal problems including the piston ring, valve train, or engine gasket	Internal engine problems can have a detrimental effect on your mower if they are not caught soon enough and fixed.	Bring your mower to your local small engine repair shop for troubleshooting

Weak Hydrostatic Transmission 

Riding mowers with a hydrostatic transmission may experience a weak transmission when the hydraulic is old or low in capacity. It can also feel weak when the drive belt or tensioner pulley is worn or broken.

Cause	Reason for Problem	Solution
Bad drive belt	A bad drive belt can cause your pump not to work efficiently	Replace a frayed or worn belt
Bad tensioner pulley	When a tensioner pulley fails, it fails to keep tension on the drive belt	Replace the pulley and grease the tensioner arm
Low or old hydraulic oil	Low or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weak	Change your hydraulic oil at regular intervals as recommended by Cub Cadet. Check your hydraulic oil periodically to ensure your hydraulic fluid is full.

Won’t Drive Straight or Steer Correctly

Several items can affect your mower’s steering including incorrect tire pressures, bad dampers, and worn steering components on lawn tractors and zero turns. The tracking may be off on zero-turn models causing the mower to veer off to the right or left.

Cause	Reason for Problem	Solution
Incorrect tire pressure	Unequal tire pressure can cause your mower to pull to one side.	Check tire pressures and keep them filled to the manufacturer’s spec. Tires on each side of your mower require equal pressure.
Bad dampers on zero turn	Bad dampers will cause your mower to jerk to one side when moving forward	Replace with a new damper
Tracking adjustment needed on zero turn	When one tire is moving faster than the other, your mower can pull to one side	Adjust the speed adjustment bolt to change the rotation speed of the tire. Refer to your owner’s manual.
Worn or loose steering components in riding mower	Worn bushings, washers, and gears can cause your mower to not steer one way or the other	Inspect and replace the parts that failed on your steering system

Won’t Move Forward or Reverse

A mower may not move due to a bad or missing drive belt, worn tensioner pulley, or missing idler spring. The transmission bypass rod and the drive release lever may be in the wrong position on your hydrostatic mower.

Detailed information can be found at:
Why Your Cub Cadet Lawn Mower Won’t Move or Go Forward

Cause	Reason for Problem	Solution
Drive release lever or bypass rod is in the wrong position	The drive release lever allows hydrostatic mowers to roll freely on a zero-turn. A bypass rod can be found on a riding mower.	The drive release lever must be in the operating position on a zero-turn. The bypass rod must be disengaged.
Drive pump belt is worn	The mower won’t move if your drive belt has fallen off. It could also not move if the belt is worn.	Replace a worn belt. Make sure the belt is securely around the pulleys.
Bad tensioner pulley	The bearing in the tensioner pulley can fail	Replace the tensioner pulley
Missing idler arm spring	If the idler arm spring breaks or goes missing, it can no longer place tension on the drive belt	Replace the broken or missing spring
Low or old hydraulic oil	Low or old hydraulic oil can fail to lubricate the hydraulic system causing your hydraulic system to seem weak	Change your hydraulic oil at regular intervals as recommended by Cub Cadet. Check your hydraulic oil periodically to ensure your hydraulic fluid is full.
Hot hydraulic fluid	Hot hydraulic fluid can be a sign of damage to your hydrostatic transmission system	Let your hydraulic oil cool. If you find your mower runs fine when it is cold, but becomes weak when the hydraulic system gets hot, have your mower checked at your local dealership.
Air in the hydraulic system	Air must be bled from the hydraulic system after changing your hydraulic fluid or the mower will not be able to move at normal speeds	Follow Cub Cadet’s procedures for changing the hydraulic fluid and bleeding air from the system in your owner’s manual.

Mower is Vibrating

Your mower may be vibrating because of loose components and hardware on the mower; failing components including bearings in the clutch, pulleys, and spindle housings; damaged or unbalanced blades, and debris lodged under the pulleys and other areas of your mower.

Detailed information can be found at:
Reasons Your Cub Cadet Mower is Vibrating

Cause	Reason for Problem	Solution
Loose or missing engine mounting bolts	Engine bolts are used to reduce the vibration of the mower when the engine is running	Secure engine bolts and replace any missing bolts
Failing clutch	When there is bearing failure and it falls out of the clutch it can cause vibration. A manual engagement clutch can have a bushing and linkages that can fail.	Replace the clutch
Unbalanced or damaged mower blades	Blades must be balanced before installing them on the mower. Vibration can be caused by unbalanced or damaged blades.	Replace any damaged blades and make sure they are balanced.
Foreign material wrapped around the blade shaft	Foreign materials like string or long weeds can get wrapped around your blade shaft causing vibration	Remove all debris and items wrapped around the blade shaft. Check for spindle damage.
Bad spindle housing bearings	Confirm vibration is not coming from bad bearings in the spindle housing	Replace the bearing in the spindle housing or replace the whole spindle housing assembly
Bad deck belt or pulleys	Check deck belt and pulleys for wear and bearing failure	Replace any damaged or worn belts and pulleys
Debris lodged in mower	Stones, acorns, woodchips, and other small items can get lodged in the mower under the pulleys or other items on your mower. Sometimes this causes your mower to shake.	Check over your mower deck and mower for any place small items can be stuck in your mower. Remove these foreign materials.

Quits When Hot

There are many reasons a mower will stop running once it gets hot. This is often caused by fuel-related issues, the wrong engine oil, the wrong amount of engine oil, plugged cooling fins, a bad ignition coil, or plugged mower deck.

Detailed information can be found at:
Your Cub Cadet Quits When It Gets Hot

Cause	Reason for Problem	Solution
Plugged air filter	Dirt and grass can plug the air filter preventing airflow	Remove the filter and clean it. Replace the filter if it is in bad condition.
Bad or Old Fuel	Fuel breaks down over time leaving behind varnish and sticky deposits.	Drain old fuel. Fill with fresh gas with an added fuel system cleaner and stabilizers like Sea Foam or STA-BIL.
Dirty Carburetor	The residue left behind by old fuel can build up and clog the fuel jet or cause internal components to fail to work.	Remove the carburetor and clean it with a carburetor cleaner. Rebuild or replace it if necessary.
Wrong Engine Oil	Using the wrong type of oil or the wrong viscosity can cause the engine to run hot.	Use air-cooled engine oil like the oils provided by Kawasaki. See the oil viscosity chart in Things That Cause a Lawn Mower to Overheat
Too Much Engine Oil	Excessive oil can cause pressure to build in the engine allowing oil to get into the cylinder through the valve train	Drain a little engine oil until it is at the manufacturer’s recommended oil level.
Too Little Engine Oil	Lack of oil can increase friction in your engine causing extreme heat in the engine	Bring to a small engine repair shop or Cub Cadet dealership to inspect engine damage. You can try adding oil, but it is often too late to fix your engine problem.
Clogged Engine Cooling Fins	The buildup of dirt and debris in the cooling fins can restrict air movement. The cooling fins push air around the engine black to keep it cool.	Clean the cooling fins and replace any broken fins. Clean around the engine block and under the engine shroud.
Bad Ignition Coil	The coil can fail to work when it gets hot and the windings on the coil separate.	Use an ohmmeter to test the ignition coil. Replace when you find a break in the continuity.
Plugged Mower Deck	A deck plugged with grass clippings will prevent the blades from easily turning under the deck. A clogged deck puts the engine under load.	Regularly scrape the mower deck to keep it clean. Avoid cutting wet grass to reduce buildup.
Internal problems including the piston ring, valve train, or engine gasket	Internal engine problems can have a detrimental effect on your mower if they are not caught soon enough and fixed.	Bring your mower to your local small engine repair shop for troubleshooting

Runs Rough or Sputters

A lawn mower that runs rough or bogs down can be due to a lack of air, fuel, or spark.

You may also experience this when you overwork the engine with a fast ground speed, low engine speed, plugged mower deck, or dull lawn mower blades.

Detailed information can be found at:
Cub Cadet Lawn Mower is Running Rough or Sputtering

Cause	Reason for Problem	Solution
Plugged Air Filter	Dirt and grass can plug the air filter preventing airflow	Remove the filter and clean it. Replace the filter if it is in bad condition.
Stuck Choke or Wrong Choke Setting	When the choke is set incorrectly the mower may begin to run rough because it is getting too much or too little air.	The choke must be adjusted to the open position once the engine is warm. Check the choke lever placement, the choke cable, and the choke plate.
Old fuel	Fuel breaks down and leaves behind varnish that can cause fuel restrictions and component failures.	Drain the fuel tank and fill it with fresh fuel mixed with a fuel additive like Sea Foam to clean the fuel system and stabilize the fuel.
Clogged Fuel Line	A clogged fuel line will restrict fuel flow.	Remove the clog in the fuel line using carburetor cleaner and compressed air. Replace the line if it is showing signs of age including cracks.
Plugged Fuel Filter	Dirt can clog the fuel filter restricting fuel flow.	Replace a plugged fuel filter.
Dirty Carburetor	Varnish left behind by old fuel can clog passageways and cause internal parts to stick.	Remove and clean the carburetor. Rebuild or replace if necessary.
Bad Gas Cap	When a gas cap no longer allows the fuel tank to vent, the tank will form a vacuum keeping sufficient fuel from getting to the carburetor.	Replace with a new gas cap.
Dirty Spark Plug	A dirty spark plug may cause an intermittent spark.	Replace with a new spark plug. Make sure it is gapped correctly and the spark plug wire is securely attached.
Fast Ground Speed	Running your mower at a fast ground speed when mowing thick, tall, or wet grass may cause the engine to work hard.	Slow down and operate the mower at a speed that matches the mowing conditions.
Low Engine Speed	Engaging the mower blades requires a lot of engine power. When operating at a low engine speed, the mower will run sluggish and bog down.	Place the throttle lever in its highest position.
Plugged Mower Deck	The engine must work harder to turn blades through a deck packed with grass clippings and debris.	Scrape the mower deck.
Dull Mower Blades	Dull blades turning through a plugged mower deck further places the engine under load.	Remove and sharpen the mower blades. Balance them before reinstalling.

Blades Won’t Engage

The mower blades may fail to engage when the deck belt is worn or has fallen off; the PTO switch is bad, or the clutch failed.

The linkages or cable on a manual engagement clutch may be worn or the battery may fail to power an electric clutch solenoid.

Detailed information can be found at:
Cub Cadet Mower Blades Won’t Engage or Turn On

Cause	Reason for Problem	Solution
Worn Deck Belt	A worn belt is unable to grip the pulleys to turn the blades.	Replace a belt that is worn, cracked, or shiny in appearance.
Belt Coming Off of the Pulleys	A worn idler arm and spring may fail to keep tension on the belt. The belt may be stretched and loose. The pulleys may not sit parallel to the deck causing the belt to come off.	Replace worn or damaged deck parts. Replace a deck belt that is stretched. Ensure the belt is routed correctly around the pulleys.
Bad PTO Switch	When the PTO switch fails to allow the battery to energize the clutch the blades won’t turn on.	Replace a bad PTO switch
Bad Clutch	The clutch is unable to transfer power from the engine to the blades when it is faulty or worn.	Replace a bad clutch.
Worn Clutch Cable, Lever, Spring & Linkages	A manual engagement clutch may not work when the clutch cable, lever, spring, or linkages are worn.	Replace worn parts.
Weak Battery	A weak battery is unable to power the clutch.	Test the battery and place it on a charger if the 12-volt battery has a reading of less than 12.7 volts.
Bad Safety Switch	When the seat switch doesn’t sense the operator, it won’t allow the blades to be engaged.	Replace a bad battery.
Blown Fuse	The fuse can blow to protect the electrical system. The mower components will not receive the required battery power.	Replace a blown fuse with the same amperage fuse. Have a mechanic find the root cause if the mower continues to blow a fuse.

Leaking Gas

It can be hard to find a leak on a mower especially when you don’t catch the leak before the gas residue evaporates.

The best thing to do is follow the fuel line out of the fuel tank and check all of the components in the path of the line.

Detailed information can be found at:
Cub Cadet Mower is Leaking Gas

Cause	Reason for Problem	Solution
Bad Carburetor Bowl Gasket	Gasket becomes dry and fails to seal allowing gas to begin leaking.	Replace the carburetor bowl gasket.
Stuck Carburetor Float or Float Needle	Old gas can cause the float or float needle to stick allowing fuel to overflow.	Clean the carburetor and replace any damaged parts.
Cracked Fuel Lines	Old fuel lines can develop cracks.	Replace an old dry fuel line.
Bad Fuel Tank	Poly tanks can leak at the seams or metal tanks can develop a rust hole.	Replace the fuel tank. Patch the tank when a new fuel tank is unavailable.
Bad Fuel Shut-Off Valve	A shut-off valve can develop a leak.	Replace the shut-off valve.
Weak Fuel Filter	Fuel can degrade plastic in the fuel filter or the plastic housing can crack.	Replace the fuel filter.
Bad Fuel Pump	The fuel pump can degrade and become weak at the seams.	Replace the fuel pump
Bad Gas Cap Seal	The seal in the gas cap can dry out and fail to seal.	Replace the fuel cap.
Cracked Primer Bulb	The bulb can crack or the line may be loose behind the primer bulb.	Replace with a new primer bulb.

Clicks and Won’t Turn Over

Detailed information can be found at:
Cub Cadet Won’t Start: Clicks and Won’t Turn Over
Mower Won’t Turn Over or Crank

Your riding mower or zero turn may just be clicking and won’t turn over. This can happen when the mower has a bad battery, ground, starter solenoid, or starter motor.

In addition to checking these items, ensure the cables and wiring are securely attached, have good continuity, and are not corroded.

Cause	Reason for Problem	Solution
Damaged or Loose Battery Cables & Wiring	Loose or corroded wiring, cables, or terminals can prevent good conductivity.	Remove corrosion and replaced damaged components. Make sure wiring and cables are securely attached.
Weak or Bad Battery	A weak battery won’t provide the power needed to start and turn over the engine.	Test the battery and place it on a trickle charger if needed. Replace a battery that won’t hold a charge.
Bad Ground	The ground cable from the battery and the ground cable from the starter solenoid must make good contact and be free of corrosion. (A 3-post solenoid is self-grounded).	Remove any corrosion and make sure it is securely grounded to the mower.
Bad Starter Solenoid	The starter solenoid can fail and will no longer actuate to engage the starter motor.	Test the starter solenoid and replace it if faulty.
Bad Starter Motor	A bad starter motor will keep the motor from starting.	Replace the starter motor.

Bad or Uneven Cut

There are several items that can cause a mower to provide a bad cut. Some of these items include a worn or damaged mower blade; uneven tire pressures; an unleveled mower deck; slow engine speed; and a plugged mower deck.

Detailed information can be found at:
Why Your Cub Cadet Lawn Mower Cuts Uneven

Dull or worn mower blade	Tire pressures uneven	Engine speed is too low
Bent mower blade	Mower deck is not level	Ground speed is too fast
Blade installed wrong	Blade spindle is bent	Deck is damaged
Deck is plugged with dirt	Bad mower deck belt or pulleys	Operator error

Engine Overheats

When the engine smells hot, you must stop running the engine right away to avoid causing extensive engine damage.

Detailed information can be found at:
Reasons a Cub Cadet Mower Engine Overheats

Cause	Reason for Problem	Solution
Wrong engine oil	Using the wrong oil for the ambient temperatures or oil not designed for air-cooled engines can cause the engine to run hot.	Drain the engine oil and fill it with fresh air-cooled engine oil with a viscosity that works best for outdoor temperatures.
Low engine oil level	Lack of lubrication causes increased friction and heat.	Change the engine oil and add fresh oil. Low oil may have caused engine damage that should be diagnosed by a small engine mechanic.
Plugged engine cooling fins	Plugged or damaged cooling fins are unable to move air to cool the cylinder heads and engine block.	Clean plugged cooling fins. Replace damaged fins.
Engine guard missing or out of place	The engine guard shields the engine to keep air circulating around the engine to keep it cool.	Securely attach the engine guard.
Plugged air filter	A very dirty air filter will starve the engine of air causing it to work harder to find air.	Replace the dirty air filter.
Mower deck full of debris	Engine work harder to turn blades through a deck full of debris.	Scrape the mower deck to remove debris.
Dull mower blades	Dull mower blades magnify the problem of a plugged deck.	Sharpen and Balance the mower blades.
Overworking the engine	Cutting long, wet, or thick grass can overwork the engine, especially when attempting more grass than the mower can handle at once.	Slow down to match your mowing conditions. Avoid cutting wet grass. Double or triple-cut an overgrown lawn.