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John Deere X120 Troubleshooting
The
John Deere X120 lawn tractor from X100 Series was manufactured between 2007 and
2010. The John Deere X120 tractor is powered by Briggs and Stratton 4-cycle
single cylinder OHV vertical shaft air-cooled gasoline engine. A 30.6 cubic
inches (0.5 L) engine has a cylinder bore of 3.56" (91 mm), piston stroke of
3.06" (78 mm), and rated power of 13.8 Hp (10.3 kW).
This model is fitted with Tuff Torq T40 hydrostatic transmission with
infinite forward and reverse gears. The John Deere X120 automatic is
equipped with a manual steering system, electric PTO clutch, disc
brakes, 15x6.00-6 front tyres, and 20x8.00-8 rear tyres. The operating
weight is 450 lbs (204 kg). The tractor is compatible with a 42"
mid-mount 2-blade mower deck with a cutting height of 1.0-4.0" (25-102
mm) and mechanical lift system.
| Engine Troubleshooting |
| Engine won't start or difficult to start |
| No fuel in fuel tank - Fill gasoline up |
| Wrong grade of gasoline - Change fuel |
| Water or air in fuel system - Remove air or water from system |
| Spark plug wiring connection is damaged - Check spark plug wiring connection, repair or change |
| Damaged spark plug - Change spark plug |
| Fuel filter is dirty - Change fuel filter |
| Defective safety switch - Replace if required |
| Carburetor is clogged - Clean the carburetor |
| Weak cylinder compression - Inspect cylinder block and change worn parts |
| Throttle cable is damaged or adjusted incorrectly - Adjust correctly or change the cable |
| Clogged cooling fins - Need to clean or wash |
| Ignition failure - Inspect ignition system and change faulty parts |
| Faulty or stuck choke cable - Change or clean the cable |
| Air filter element is plugged - Service or replace air filter |
| Fuel pump is dirty or defective - Check fuel pump and replace if necessary |
| Engine starts but immediately stops |
| Spark plug is faulty - Spark plug need to be replaced |
| Carburetor is defective or clogged - Service or change carburetor |
| Faulty ignition coil - Change ignition coil as required |
| Bad or damaged valve springs - Valve springs need to be changed |
| Valves sticking - Clean the valves |
| Low engine oil level - Check and refill engine oil |
| Engine is under excessive load - Load reducing required |
| Cooling fins are clogged - Need to clean or wash |
| Too lean carburetor mixture - Use proper settings |
| Ignition timing is incorrect - Ignition timing needs to be adjusted correctly |
| Valve setting is wrong - Adjust valves as required |
| Stale gasoline - Use proper fuel |
| Engine is running overloaded - Reduce the load |
| Lack of engine oil - Checking oil level and add if necessary |
| Low idle speed adjustment is incorrect - Adjust the low idle speed |
| Clogged or damaged fuel pump - Clean or install new fuel pump |
| Main bearings or crankshaft are worn out - Replace crankshaft or bearings |
| Valve clearance is incorrect - Adjust valve clearance according to specifications |
| Worn cylinder bore or piston rings - Replace defective components |
| Carburetor is dirty or incorrectly adjusted - Clean or correctly adjust carburetor |
| Air filter element is clogged - Service or change air filter |
| Fuel pump is defective or dirty - Clean or replace fuel pump |
| Defective ignition system - Check ignition and replace faulty components |
| Cylinder head gasket is defective - Cylinder-head gasket replacement required |
| Valves are burned or stuck - Service or change valves |
| Push rod is damaged or worn - Push rod needs to be changed |
| Damaged cylinder block components - Defective components need to be replaced |
| Engine using too much gasoline |
| Choke opening is not full - Replace or adjust choke cable |
| Improper carburetor main jet adjustment - Adjust the carburetor main jet properly |
| Spark plug is loose or defective - Replace or tighten spark plug |
| Stuck, burned, or worn valves - Change or clean valves |
| Piston, sleeve, or rings are damaged - Replace faulty components as required |
| Valve clearance is wrong - Adjustment procedure required |
| Excessive engine oil consumption |
| Worn seals or gaskets - Change worn parts according to specifications |
| Valve guides and stems are worn - Install new valves |
| Piston rings are seized or worn - Install new piston rings |
| Piston or cylinder liner is worn - Inspect piston and liner, fit new components as necessary |
| Breather pipe or hose is blocked - Replace or service |
| Hydrostatic Transmission Troubleshooting |
| Hydrostatic transmission is making noise |
| Speed control linkage is defective or unadjusted - Adjust or change linkage |
| Transmission is under excessive load - Reduce the load is required |
| Transmission oil is contaminated or oil level is insufficient - Add oil to proper level or pour fresh transmission oil |
| Defective or worn transmission parts - Check hydrostatic transmission components for defect or damage and change if necessary |
| Shift linkage is stuck or worn - Clean or replace linkage |
| Seized or worn hydrostatic pump - Replace or repair pump |
| Faulty or misadjusted transmission shift control parts - Change or adjust correctly |
| Transmission fluid level is low - Check and refill the transmission fluid |
| Faulty or worn drive sheave - Replace sheave |
| Faulty or unadjusted shifting linkage - Adjust correctly or replace linkage |
| Speed control pedal linkage is bent or not adjusted - Adjust or replace linkage |
| Damaged transmission seals or gaskets - Install new seals or gaskets |
| Final drive shaft leakage - Shaft seals need to be changed |
| Cracked transmission case - Replace defective case or transmission assembly |
| Mower Deck Troubleshooting |
| Mower vibrates excessively |
| Damaged or clogged mower drive pulley - Replace or clean pulley |
| Worn or loose drive belt - Install a new belt or adjust belt tension |
| Bent or unbalanced cutting blades - Change or balance blades |
| Loose blade mounting bolts - Bolts need to be tightened |
| Discharge chute keeps clogging |
| Fast mowing speed - Select a slower speed |
| Grass is too long - Use a lower cutting height |
| Reduced engine rpm - Open choke fully |
| Cutting level is too low - Adjust mower to higher cutting height |
| Drive belt installed improperly - Check drive belt for correct installation |
| Mower leaving random uncut of grass |
| Mower deck is clogged - Check cutting deck and clean as necessary |
| Blades are too dull - Blades need to be sharpened |
| Defective or worn blades - Blades must be changed |
| Fast mowing speed - Need to slow down |
| Low cutting height - Adjust mower to higher cutting height |
| Grass bag is overfilled - Grass bag must be empty |
| Blades are scalping the grass |
| Lawn is bumpy or not smooth - Level the lawn |
| Low cutting height - Must be set to high cutting height |
| Ground speed is too fast - Operate at slower speed |
| Mower deck is not leveled properly - Level the deck correctly |
| Bent or worn blades - Blades must be changed |
| Tires are not correctly inflated - Check and inflate the tires |
| Low tire inflation - Inflate tires as required |
| Incorrect level of mower deck - Level the deck properly |
| Blades are not sharp - Need a blade sharpening |
| Damaged or worn blades - Replace the blades |
| Discharge chute is plugged - Clean out the mower deck |
| Deck shell is damaged - Replace or rebuild mower deck |
| Mower spindle is faulty or loose - Repair or replace the spindle |
| Electrical Troubleshooting |
| Battery will not charge |
| Wiring connections are loose or corroded - Tighten or clean connections |
| Electrical terminal connectors are defective - Install new terminal connectors |
| Battery is worn - Battery change required |
| Battery voltage is low - Battery needs to be recharged |
| Battery won’t hold charge - Service or change the battery |
| Bad terminals or disconnected battery cables - Connect wires correctly or change terminals |
| Battery is discharged or worn - Battery needs to be recharged or replaced |
| Wiring is improperly connected or disconnected - Check wiring and connect properly |
| Battery capacity is low - Charge the battery |
| Spark plug faulty or incorrectly gapped - Replace or clean and gap |
| Starter motor or solenoid failing - Replace solenoid or repair starter |
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| Lawn and Garden Tractors Technical Specs |
