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John Deere X120 Tractor Troubleshooting

JD X120 Engine Troubleshooting

Engine not starting

No gasoline in tank - Add fuel.
Incorrect fuel grade - Change gasoline.
Old gas - Drain fuel and add fresh.
Dirt and debris in fuel system - Remove debris and dirt.
Spark plug wires are damaged - Check wires connection.
Faulty spark plug - Test ignition spark.
Clogged fuel filter - Replace fuel filter.
Defective safety switch - Replace if required.
Carburetor is clogged - Clean the carburetor.
Inspect starter cranking speed RPM. Compression problems.

Engine hard starting

Spark plug wear - Inspect the spark, change if necessary.
Carburetor incorrectly set - Set carb correctly.
Dirt in fuel lines - Service required.
Throttle cable damaged - Change the cable.
Old or incorrect fuel - Drain and add proper fuel.
Electrical wires are damaged - Check and replace.
Starter fault - Check starter, repair or replace.

Engine stalling, surging or running rough

Cooling fins plugged - Clean and wash cooling fins.
Loose electrical connections - Inspect and repair defective contacts.
Ignition setting defective - Check ignition and adjust if necessary.
Choke cable sticking - Repair or change as needed.
Air filter blocked - Clean or change air filter.

Engine misses under load

Spark plug wear - Check spark plug for fouled condition and proper gap.
Carburetor is not adjusted correctly - Adjust carburetor as required.
Ignition coil defective - Test ignition coil and replace if necessary.

John Deere X120 Engine overheating

Engine overloaded - Reduce loads.
Cooling fins or air inlet plugged - Clean dirty components.
Engine oil low or too high - Checking oil level and oil pressure.
Low quality engine oil - Change oil.
Inspect crankshaft to main bearing clearance.
Too Fast idle - Adjust carburetor idle mixture screw.

Engine does not idle

Spark plug not gapped correctly - Tighten the spark plug correctly.
Spark plug failed - Inspect the spark, replace if necessary.

John Deere X120 Engine knocks

Low octane fuel - Use proper gasoline.
Engine overload - Reduce loads.
Lack of engine oil - add oil as required.
Low engine speed - Adjust carburetor as needed.
Piston rings and cylinder bore worn - Replace defective components.
Inspect for engine overheats from clogged cooling fins.
Inspect and adjusting crankshaft end play.
Check for worn crankshaft or camshaft bearings.

Engine back-fire

Check spark plug for fouled.
Check and adjust the choke.
Checking and adjusting carburetor.
Checking and adjusting ignition coil air gap.
Inspect for sticking valves.
Checking and adjusting valve clearance.
Inspect flywheel key.

Engine lacks power

Engine overheats - Replace air cleaner.
Excess engine oil - Excess oil needs to be drained.
Fuel pump broken - Repair or replace fuel pump.
Defective governor - Checking and adjusting governor.
Inspect carburetor for plugged passages.
Test engine compression.

Excessive Fuel Consumption

Throttle does not open well - Replace throttle cable.
Carburetor problems - Check and adjust carburetor.

Exhaust with black smoke

Air cleaner is dirty or oiled - Clean or replace filter.
Choke partially engaged - Replace or repair choke.
Checking and adjusting carburetor float level.

JD X120 Electrical Troubleshooting

Starter does not function

Main fuse defective - Fit new fuse.
Battery terminals are corroded - Inspect and clean contacts.
Low battery voltage - Need to charge the battery.
Ignition lock problems - Change switch.
Faulty starter - Replace or repair.
Wires disconnected - Reconnect wires.

Battery doesn't charge

Faulty cell in battery - Fit new battery.
Battery terminals and cables are dirty - Inspect and Clean.

Lights do not work

Light plug not connected.
Replace the lamps.
Short-circuit in cable.

John Deere X120 Machine Problems

Tractor vibrates too much or rattles excessively

Attachment driven belt worn or damaged - Inspect and replace damaged belt.
Worn traction drive belt - Installing new driven belt.
Drive sheaves are dirty - Change if necessary.
The mower deck blades are bent or unbalanced - Change as needed.

Engine runs but tractor won't move

Parking brake is applied - Unlock park brake.
Bypass valve pulled out - Deactivate the bypass valve.
Loose lawnmower blades - Checking blades for loose bolts.
Poor blade balancing - Check blades for damage and balance as required.
Too little transmission oil - Check transmission oil lever.

John Deere X120 Mower Deck Troubleshooting

Discharge Chute Plugged

Operating at a faster ground speed - Operate the mower at low speed.
Grass has grown too long - Adjust cutting height.
Grass too wet - Don't mow while wet grass.
Engine rpm too low - Open throttle fully.
Loss of airflow - Set higher revs.
Low cutting height - Choose the correct cutting height.
Belt fitted improperly - Reinstall the belt properly.

Uncut grass during operation

Mower's cutting deck is clogged - Deck cleaning required.
Excessive blade wear - Check for blade damage and replace if necessary.
Deck level is too low - Adjust and level the deck height.
Bagger too full - Clean grass bag.
Speed is very fast - Do not use high speed.

Belt Slipping

Dirt in the pulley - Clean or replace.
Belt is worn out - Check and replace belt.
No belt tension required - Install the belt correctly.

The lawn mower vibrates excessively

Mower clogged or in pulleys - Clean deck and pulley from debris.
Damaged pulleys or belt - Replace worn parts.
Pulleys or belt misaligned - Inspect and adjust.
The blades are unbalanced - Blades need balancing.

Blades scalping grass

Cutting height improper - Check and adjust height.
Mower wheels not adjusted correctly - Adjust mower deck wheels.
Low tire pressure - Tire pressure required.
High blade speed during mowing - Correct blades speed.
Blades are bent - Replace blades.

Uneven cutting results

Deck level is too low - Adjust and level the deck height.
Tire pressure unequal - Increase tire pressure.
Incorrect rollers height - Check wheel adjustment.
Speed too high - Use slower speed.
Blades dull - Install new blade.

JOHN DEERE TRACTORS ATTACHMENTS
420	430	455	790	990
X300	X320	X330	X350	X475
X485	X500	X540	X570	X590
X700	X720	X738	X758	1023E
2025R	2210	2520	3025E	3032E
3038E	3038R	3039R	3046R	3203
3320	3520	4052R	4066R	4100
4105	4115	4200	4310	4320
4400	4410	4520	4600	4720

JD TRACTORS TROUBLESHOOTING
2640	3040	3310	3650	4100
5050D	5090R	5410	6105R	7200R
E130	L111	LA110	LT155	X300R