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John Deere 125 Tractor Problems

John Deere 125 Engine Problems

Tractor engine won't start

Gas tank is empty - Add fuel.
Improper fuel grade - Use correct fuel grade.
Old gas - Drain fuel and replace with fresh fuel.
Dirty fuel system - Check and clean.
Spark plug wire is loose or disconnected - Inspect and replace if required.
Faulty spark plug - Spark plugs need to be replaced.
Fuel filter is clogged - Change fuel filter.
Defective safety switch - Replace if required.
Carburetor malfunction - Check and repair as required.
Check and adjust governor linkage. Test crankcase vacuum.

Engine hard starting

Spark plug malfunction - Inspect the spark, change if necessary.
Carburetor is dirty - Wash, clean and adjust.
Fuel pipes are clogged - Clean the system carefully.
Choke cable not adjusted properly - Checking and adjusting.
Stale or incorrect fuel - Drain and add proper fuel.
Electrical wiring worn out - Checking and replace.
Starter problems - Check the starter and replace defective components.

Rough running engine

Cooling fins plugged - Clean cooling fins.
Loose electrical contacts - Check and restore damaged connections.
Incorrect ignition settings - Test ignition and spark plug.
Choke cable sticks - Check and replace.
Air filter element clogged - Clean or change air filter.

JD 125 Engine runs but misses

Spark plug fail - Check spark plug for fouled condition and proper gap.
Carburetor defective or not adjusted - Repair or adjust.
Ignition coil is damaged - Inspect ignition coil and change if required.

Engine overheats

Excessive engine load - Reduce loads.
Air intake screen blocked - Clean dirty components.
Engine oil low or too high - Inspect oil pump for damage or worn.
Poor quality oil - Change oil.
Check internal bearing clearance.
Idle speed problems - Adjust fast idle.

Engine doesn't idle speed

Spark plug is loose - Check spark plug gap.
Spark plug wear - Check the spark and replace defective spark.

John Deere 125 Engine knocks

Stale or low octane fuel - Change fuel.
Excessive engine load - Reduce loads.
Low oil level - add oil as required.
Engine speed too low - Adjust carburetor.
Cylinder bore and rings worn out - Inspect and replace if required.
Check for engine overheating from plugged cooling fins.
Check and adjust crankshaft end play.
Inspect for loose or wear connecting rods.

Engine backfires

Inspect spark plug and change if required.
Inspect and adjust choke.
Test carburetor, adjust if necessary.
Inspect and adjust ignition coil air gap.
Check inlet and outlet valves.
Check and adjust valve clearance.
Inspecting flywheel key.

Insufficient engine power

Engine overheating - Clogged air filter element.
Overfilling engine oil - Drain excess oil.
Fuel pump problems - Test fuel pump output.
Defective governor - Inspect and repair governor.
Inspect and repair carburetor.
Checking engine compression.

Excessive Fuel Consumption

Choke doesn't open well - Replace choke cable.
Carburetor is not working properly - Adjust or repair carburetor.

Emits black smoke

Air filter element clogged - Clean or change filter.
Throttle not fully engaged - Replace or repair choke.
Check oil fill dipstick O-ring seal or cracked cap.

JD 125 Electrical Troubleshooting

Starter motor will not turn engine

Fuse is defective - Install new fuse.
Battery terminals are corroded - Inspect and clean terminals.
Low charging voltage - Battery charging required.
Ignition lock problems - Replace the lock.
Starter is damaged - Replace or repair.
Wiring damage - Reconnect wires.

Battery doesn't charge

One or several cells defective - Change the battery.
No contact between cable and battery terminal - Replace or clean cable.

Lighting does not function

Light connector defective.
Bulbs defective.
Short circuit in electrical wires.

John Deere 125 Machine Problems

The machine vibrates

Attachment driven belt worn or damaged - Belt replacement required.
Traction drive belt worn - Inspect and replace traction belt.
Drive pulley malfunction - Replace if necessary.
The mower deck blades are bent or unbalanced - Replace defective blades.

Engine runs but tractor won't move

Parking brake is applied - Release the park brake.
Bypass valve lever in the push position - Disengage the bypass valve lever.
Mower blades are loose - Inspect and fasten securely if necessary.
Poor blade balancing - Inspect the blades and balance if necessary.
Too little transmission oil - Check transmission oil lever.

John Deere 125 Mower Deck Troubleshooting

Discharge Chute Plugged

Speed too high - Use slower speed.
Grass has grown too long - Adjust the mower to a lower cutting height.
Wet grass - Wait for the grass to dry.
Low engine speeds - Open choke wide.
Loss of airflow - Check engine rpm.
cut too low - Use higher cutting.
Incorrect belt installation - Check belt installation.

Streaking of uncut grass

Clog in discharge area - Check cutting deck and clean if necessary.
Defective blade - Check and replace the blade.
Mower deck low - Level mower deck.
Grass bagger overfilled - Empty the grass bag.
Traveling too fast - Operate the mower at low speed.

Belt slips

Debris in sheaves - Recommend cleaning the sheaves.
Belt is damaged - Check and change damaged belt.
Belt tension problems - Check belt tension.

The lawn mower vibrates excessively

Debris on mower deck or in sheaves - Remove clogging from sheaves or mower deck.
Damaged mower belt or pulleys - Change damaged parts.
Belt or sheaves out of centering - Check and align.
No blade balance adjustment - Balance the blades.

Blades scalping grass

Cutting height improper - Raise cutting height.
Mower height wheels not adjusted - Adjust rear or front wheel height.
Insufficient tire pressure - Increase tire pressure.
Blades speed too fast - Adjust the speed of blades.
Blades are bent - Remove bent blade and fit new one.

Uneven cutting results

Mower deck not leveled properly - Deck leveling required.
Insufficient tire pressure - Increase tire pressure.
Incorrect rollers height - Check the wheel heights.
Gear too fast - Choose recommended speed.
Blades dull - Sharpen or replace 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