Even though Gravely makes a well-built lawn mower, it will not be problem free. Like with any mechanical item you purchase, when you own it long enough, you’re bound to run into a problem.
I put together this guide to help you identify the causes of the problems that develop in your Gravely lawn mower.
To keep your mower running at its best, regularly clean your mower, check the engine oil and hydraulic oil, clean the air filter, sharpen the blades and scrape the deck.
Perform routine oil changes as required for your Gravely mower. Check out this guide on servicing your Gravely zero turn.
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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.
Common Gravely Lawn Mower Problems & Solutions
1. Won’t Start
A Gravely lawn mower requires air, fuel, and spark to start and run. When it lacks any of these three items, it will fail to start. The items that can keep your mower from starting are old fuel; plugged air filter; clogged fuel lines; plugged fuel pump; a dirty carburetor; a dirty spark plug; a bad ignition switch; a bad battery; and a faulty charging system.
Detailed information can be found at:
Your Gravely Mower Won’t Start: Solved!
| 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 | Try to clean the cap and remove 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 the components making up 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 or coil | Your mower will not start when either the ignition switch or coil is bad | Test and replace a bad switch |
2. Starts Then Dies
Many of the items that can prevent your Gravely lawn mower from starting will also cause it to shut down after running. In addition to these items, the mower can overheat and shut down. This can be the result of a plugged air filter; plugged or broken cooling fins; or an insufficient oil level.
Check for a bad ignition coil, plugged mower deck, bad gas cap, or incorrect choke setting as well. These items can cause the mower to die after it starts.
Detailed information can be found at:
Your Gravely Mower Starts Then Dies
| 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 or filter | 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 a plugged fuel filter. |
| Dirty carburetor | The carburetor can become dirty and clogged due to bad fuel and ethanol deposits preventing fuel flow | Clean all components making up the carburetor. Replace if needed. |
| Too Much Engine Oil | Too much engine oil increases pressure in the crankcase causing it to overheat and die | Correct your engine oil level by removing a little oil |
| Bad Spark Plug | Dirty or damaged spark plug causes the plug to foul out and cause intermittent running problems. | Clean or replace spark plugs if needed. Ensure spark plug wires are securely attached and the plug is gapped correctly. |
| Faulty Ignition Coil | Windings on the coil can separate and short out on a bad ignition coil | Check for a break in the continuity using an ohm meter and replace is found bad |
| Choke is in the Wrong Position | A choke is used for cold starts. The choke can cause your engine to shut off when it continues to restrict airflow after the engine warms. | Make sure the choke is in the correct position |
| Battery is Not Charging | A battery that doesn’t hold a charge or a bad charging system that can’t keep the battery charged will cause your Gravely mower to die after running. | Test your battery and charging system. Replace any electrical components found to be bad. Read more about testing your battery and charging system here. |
| Bad Gas Cap | Gas caps have vents for air to pass through. When the vents get plugged, the fuel tank will cause fuel restrictions. | Replace a fuel cap that no longer vents |
| Clogged Mower Deck | Clogged mower deck causes a strain on the engine causing it to work hard and possibly shut down | Periodically scrape your mower deck to keep it clean |
3. Mower is Smoking
Smoke coming from a Gravely lawn mower can be caused by something as simple as spilled oil when completing an oil change. Oil burning off a hot engine or muffler can cause the mower to smoke.
Smoke can also indicate you have a more serious problem developing in the mower. This could be a valve or piston ring problem.
Detailed information can be found at:
Your Gravely Mower is Blowing Blue, Black or White Smoke: Find Out Why!
| 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. |
| Engine oil level is too low | Lack of oil can increase friction in your engine causing extreme heat. | Bring to a small engine repair shop to inspect engine damage. You can try adding oil, but it is often too late to this 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 Gravely mower to your local small engine repair shop for troubleshooting |
4. Weak Hydrostatic Transmission
A hydrostatic transmission on a Gravely lawn mower can feel weak from the use of a bad hydraulic belt or pulley. Old hydraulic oil or not having enough oil in the hydraulic tank can also result in a weak transmission.
| Cause | Reason for Problem | Solution |
| Bad drive belt | A bad drive belt can cause your pump not to work efficiently | Replace a frayed, cracked, 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 Gravely. Check your hydraulic oil periodically to ensure your hydraulic fluid is full. |
5. Won’t Drive Straight or Steer Correctly
Several items can affect your Gravely mower’s steering including incorrect tire pressures and worn steering dampers. It is good to check the tracking on your mower.
When the unit is not tracked correctly, your mower can veer off to one side and not drive straight.
| 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. |
6. Won’t Move
Before you check anything on your Gravely mower, first check to drive bypass valves are not the cause of your moving problem. These are valves located at the rear of your mower that disengages the hydros so you can manually push the mower.
When these valves are bypassed, the mower will free-roll, but will not drive. Make sure the bypass valves are in the operating position.
Once you confirm the bypass valves are not the problem, check for a bad drive belt, broken tensioner spring, or worn tensioner pulley.
A problem in your hydraulic system where the fluid is hot, at a low level, or air is caught in the system can cause your mower to move slowly or not move at all.
Detailed information can be found at:
9 Reasons Your Mower Won’t Move or Go Forward
| Cause | Reason for Problem | Solution |
| Drive release lever in the wrong position | The drive release arms allow hydrostatic mowers to roll freely | The drive-release arms must be in the operating position. |
| 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 or cracked 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 Gravely. 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 Gravely 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 Gravely’s procedures for changing the hydraulic fluid and bleeding air from the system as outlined in your owner’s manual. |
7. Mower is Vibrating
Mowing with your Gravely mower isn’t always the most comfortable task even if you have a nice suspension seat installed. Running your mower over the uneven ground can have you bouncing around on your mower.
Add a severe vibration in your mower, you may feel like you’re going to shake right out of your seat.
Small debris lodged in your Gravely mower, worn engine mounting bolts or bad mower deck components can cause a vibration.
Detailed information can be found at:
Your Gravely Lawn Mower Vibration
| 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 |
| Clutch is bad | 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 | Damaged and unbalanced blades can send a vibration through your mower. Blades must be balanced before installing | Replace any damaged blades and make sure they are balanced. |
| Material wrapped around the blade spindle | 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 | Vibration can be caused by a bad bearing in the spindle housing. | Replace the bearing in the spindle housing or replace the whole spindle housing assembly |
| Worn pulleys or deck belt | Check deck belt and pulleys for wearing of the belt and bearing failure in the pulleys | Replace any damaged or worn belts and pulleys |
| Debris lodged in mower | The smallest little things can cause your Gravely to excessively vibrate. Check over your mower for debris stuck in the deck or mower. Don’t overlook the small stuff. | Check over your mower deck and mower for any place small items can be stuck in your mower. Remove these foreign materials. |
8. Bad or Uneven Cut
An uneven cut with your Gravely mower isn’t always a problem in the mower deck. It can be something as simple as a low tire that can cause your mower not to sit level. Always check the tire pressure first and then move on to looking at your mower deck.
Detailed information can be found at:
Reasons Your Gravely Lawn Mower Cuts Uneven
| Worn mower blade | Uneven tire pressures | Engine speed is too low |
| Bent mower blade | Unleveled mower deck | Ground speed is too fast |
| Blade installed wrong | Bent blade spindle or spindle bearing | Damaged deck shell |
| Clogged Mower Deck | Worn deck pulleys or belt | Operator error |
9. Leaking Gas
Locating the actual spot your Gravely lawn mower is leaking can be more challenging than you might think. You may not notice you have a gas leak until you see a trail of burnt grass or smell a strong odor in your storage shed.
By the time you get to look at your mower, the leaked fuel may have already evaporated into the air leaving no clues.
Your mower can develop leaks in the fuel system because old gas degrades your components over time. It can make mechanical parts fail or cause plastic housings to become weak and leak.
Detailed information can be found at:
Your Gravely Mower is Leaking Gas
| Cause | Reason for Problem | Solution |
| Dirty of Failed Carburetor | The carburetor can collect a buildup of substances remaining from old gas that can cause blockages or parts failures | Clean the carburetor and replace any damaged parts |
| Old Fuel Filter | Filter can become plugged | Replace fuel filter |
| Bad Fuel Pump | Pump can wear and deteriorate over time and may begin leaking at the seams | Replace the fuel pump |
| Bad Fuel Tank | A poly tank can leak at the seams of the tank. | Replace the fuel tank. |
| Bad Fuel Shut-Off Valve | Metal and plastic shut-off valves are prone to leaking | Replace the shut-off valve |
| Cracked Fuel Lines | Rubber fuel lines become dry and cracked causing gas to leak | Replace the fuel lines |
| Bad Seal in the Gas Cap | The gas cap seal can fail and no longer seal allowing gas to splash out of the fuel tank around the gas cap | Replace the gas cap |