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John Deere D125 Problems

John Deere D125 Engine Troubleshooting

Engine not to start

Empty fuel tank - Fill fuel up.
Improper fuel grade - Change gasoline.
Old gasoline - Drain fuel and fill up fresh.
Clogged fuel system - Remove clogging.
Spark plug defective - Replace if necessary.
Faulty spark plug - Check ignition spark.
Dirty fuel filter - Fit new filter.
Brake pedal not depressed - Press the brake pedal.
Carburetor problems - Carburetor diagnostics required.
Inspect starter cranking speed RPM. Check and adjust valve clearance.

Engine hard starting

Spark plug wear - Check the spark and replace defective spark.
Carburetor incorrectly set - Set carb correctly.
Dirt in fuel pipes - Service required.
Worn throttle cable - Replace as required.
Stale or incorrect gasoline - Fill in proper fuel.
Electrical connection problems - Inspect and change.
Starter is not working - Test starter and repair if necessary.

Engine runs roughly

Cooling fins plugged - Remove dirt from cooling fins.
Loose electrical contacts - Inspect and replace defective contacts.
Ignition adjust incorrect - Test ignition and spark plug.
Throttle cable sticking - Check and repair.
Air filter dirty - Clean air filter.

Engine misses under load

Spark plug malfunction - Inspect spark plug wire.
Carburetor defective or not adjusted - Repair or adjust.
Ignition coil air gap incorrect - Check and adjust ignition coil air gap.

Engine overheats

Engine overloaded - Reduce loads.
Air intake screen clogged - Clean dirty components.
Too little or too much oil - Inspect oil pump for damage or worn.
Low quality engine oil - Change engine oil.
Inspect crankshaft to main bearing clearance.
Too Fast idle - Adjust fast idle.

Engine doesn't idle speed

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

JD D125 Engine knocking

Stale gasoline - Use proper gasoline.
Excessive engine load - Reduce the load.
Oil level low - add oil as required.
Engine speed too low - Adjust the speed.
piston rings or cylinder bore damaged - Replace defective components.
Inspect for engine overheats from clogged cooling fins.
Inspect and adjusting crankshaft end play.
Check for loose or worn connecting rods.

Engine back-fire

Checking spark plug.
Adjust or replace throttle.
Check and adjust carburetor.
Checking and adjusting ignition coil air gap.
Check inlet and outlet valves.
Checking and adjusting valve clearance.
Inspect flywheel key.

Insufficient engine power

Engine overheating - Check air cleaner for plugged condition.
Excess engine oil - Remove excess oil.
Faulty fuel pump - Inspect and repair fuel pump.
Faulty governor - Inspect and adjust governor.
Inspect and repair carburetor.
Test engine compression.

Engine getting too much fuel

Choke didn't open fully - Adjust choke cable.
Carburetor is not working properly - Checking and adjusting carburetor.

Black exhaust smoke

Air cleaner is dirty or oiled - Clean or change filter.
Choke not fully engaged - Replace or repair choke.
Check and adjust carburetor float level.

John Deere D125 Electrical System Troubleshooting

Starter does not function

Main fuse malfunction - Fit new fuse.
Poor terminal connection - Clean terminals.
Low-voltage battery - Charge the battery.
Ignition switch is damaged - Replace switch.
Starter fault - Change the starter.
Wiring disconnected - Change wiring.

Battery will not charge

Faulty cell in battery - Replace the battery.
Poor contact between cable and battery pole - Inspect and Clean.

Lighting does not function

Connection/disconnection level in wrong position.
lamp does not work.
Wiring damaged.

JD D125 Machine Problems

Tractor vibrates excessively

Attachment driven belt worn or damaged - Inspect and change damaged belt.
Worn traction drive belt - Installing new driven belt.
Drive pulley malfunction - if required.
Mower blades malfunction - Tighten and balance blade.

Machine does not move while engine is running

Parking brake is applied - Unlock park brake.
Bypass valve pulled out - Deactivate the bypass valve.
Mower blade could be loose - Check mower blades and fasten as required.
Poor balancing after sharpening - Check mower blade balancing.
Transmission oil is insufficient - Add oil to the transmission.

John Deere D125 Mower Deck Troubleshooting

Discharge Chute Clogged

Lawn mower is driving too fast - Use slower speed.
Grass too long - Adjust cutting height.
The grass is wet - Do not use the mower if grass is wet.
Engine rpm reduced - Adjust carburetor to higher rpm.
Loss of airflow - Check engine rpm.
Cutting too low - Adjust cutting settings.
Belt installed incorrectly - Fit belt correctly.

Patches of grass uncut

Debris in mower deck - Mower deck needs cleaning.
Excessive blade wear - Check and replace the blade.
Mower deck is low from ground - Level mower deck.
Grass bagger overfilled - Clean grass bag.
Traveling too fast - Do not use high speed.

Slipping drive belt

Dirt in the sheaves - Check and clean.
Drive belt wear - Check and change damaged belt.
Poor belt tension - Check belt tension.

The lawn mower vibrates excessively

Debris in pulleys or in mower deck - Clean pulley and deck from debris.
Damaged sheaves or belt - Fit new components.
Belt or sheaves out of centering - Check and centering.
Improper blade balancing - Balance blades correctly.

Blades scalp grass

Incorrect height cutting - adjust cutting height.
Mower wheel height incorrect - Adjust wheel heights correctly.
Low tire pressure - Inflate tires as required.
Higher blade speed - Correct blades speed.
Bent blades during operation - Install new blades.

Uneven Cut

Mower deck not level - Checking and adjust deck height.
Tire pressure uneven - Need to inflate tires.
Wrong wheel position - Check wheel adjustment.
Gear too high - Need to reduce speed.
Mower blade worn or bent - Check and replace the 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