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John Deere 425 Troubleshooting

John Deere 425 Engine Problems

Engine will not start

No fuel in fuel tank - Fill gasoline up.
Incorrect fuel grade - Use correct fuel grade.
Stale fuel - Drain gasoline and add fresh.
Fuel system clogged - Repair or replace.
Spark plug defective - Check the spark plug wires.
Spark plug damaged - Spark plugs need to be replaced.
Fuel filter is dirty - Fuel filter needs to be replaced.
Faulty safety switch - Change damaged switch.
Incorrect carburetor adjustment - Adjust carburetor idle mixture screw.
Inspect and adjust throttle cable. Check the Valves and Compression System.

Engine long starting

Spark plug malfunction - Check the spark and change defective spark.
Carburetor incorrectly set - Set carb correctly.
Dirt in fuel lines - Servicing fuel system.
Worn throttle cable - Replace as required.
Old or incorrect fuel - Pour quality fuel.
Electrical connection problems - Checking and replace wiring if necessary.
Starter fault - Inspect the starter and change defective parts.

Engine stalling, surging or running rough

Plugged cooling fins - Clean and wash cooling fins.
Loose electrical contacts - Check and repair damaged connections.
Ignition system problems - Test ignition and spark plug.
Choke cable sticking - Check and replace.
Air filter dirty - Clean or replace the air filter.

Engine runs but misses

Spark plug fail - Replace spark plug.
Carburetor malfunction - Inspect and overhaul.
Ignition coil defective - Test ignition coil and replace if necessary.

Engine overheating

Engine overloaded - Reduce loads.
Air intake screen clogged - Clean and wash dirty components.
Too little or too much oil - Inspect oil level.
Low quality engine oil - Change oil.
Check internal bearing clearance.
Fast idle speed - Adjusting fast idle speed.

Engine does not idle

Spark plug not gapped correctly - Check spark plug gap.
Spark plug wear - Inspect the spark, replace if necessary.

JD 425 Engine knocks

Stale fuel - Use proper fuel.
Excessive engine load - Reduce loads.
Lack of engine oil - Add engine oil.
Low engine speed - Adjust carburetor as needed.
Piston rings and cylinder bore worn - Replace defective components.
Check for engine overheating from plugged cooling fins.
Check and adjust crankshaft end play.
Check for carbon build-up in combustion chamber.

Engine backfires

Check spark plug for fouled.
Inspect and adjust choke.
Check and adjust carburetor.
Check and adjust ignition coil air gap.
Inspect for sticking valves.
Test valve clearance, adjusting if necessary.
Inspect flywheel key.

Insufficient engine power

Engine overheats - Clean or replace air filter.
Engine oil overfilled - Remove excess oil.
Fuel pump problems - Test fuel pump output.
Governor problems - Repair or replace governor.
Inspect and repair carburetor.
Test engine compression.

Engine gets too much gas

Insufficient choke opening - Check choke cable.
Carburetor is not working properly - Adjust carburetor.

Emits black smoke

Air filter element plugged - Clean or replace filter.
Choke not fully engaged - Inspect and adjust choke.
Inspect carburetor needle valve and seat for wear or damage.

John Deere 425 Electrical System Troubleshooting

Starter does not run

Blown main fuse - Check and replace.
Battery terminals are corroded - Inspect and clean contacts.
Low-voltage battery - Charge the battery.
Ignition switch problems - Change switch.
Starter is damaged - Repair or replace.
Electrical wires are damaged - Reconnect wires.

Battery doesn't charge

Battery cells defective - Change the battery.
No contact between cable and battery terminal - Clean or replace cable.

No Lights work

Headlight wire connector disconnected.
Replace light bulbs.
Short-circuit in cable.

JD 425 Machine Problems

Tractor vibrates excessively

Equipment drive belts worn out - Check and change worn belt.
Worn traction drive belt - Inspect and replace traction belt.
Drive sheaves are dirty - if required.
Unbalancing or bending of blades - Replace defective blades.

Machine does not move while engine is running

Parking brake locked - Release the parking brake.
Bypass valve pulled out - Disengage the bypass valve lever.
Loose lawnmower blades - Check mower blades and fasten as required.
Improper blade balance - Balance the blades correctly.
Low transmission oil - Pour oil as required.

John Deere 425 Lawn Mower Troubleshooting

Plugged discharge chute

Traveling too fast - Use slower speed.
Too high grass for mowing - try operating a short cutting height.
The grass is wet - Wait until the grass dries.
Engine is running at too low speed - The throttle is not fully open.
Restricted air flow - Set higher revs.
cut too low - Change cutting height.
Incorrect belt installation - Fit belt correctly.

Patches of grass uncut

Cutting deck clogging - Inspect and clean cutting deck.
Blade wornout - Check and replace the blade.
Mower deck is low from ground - Leveling the mower deck.
Bagger too full - Empty the grass bag.
Speed is very fast - Do not use high speed.

Belt Slipping

Dirt in the sheaves - Recommend cleaning the sheaves.
Drive belt wear - Check and change damaged belt.
Belt tension problems - Adjust belt tension.

Too much mower vibration

Debris in pulleys or in mower deck - Clean deck and pulley from debris.
Worn sheaves or belt - Change defective parts.
Misaligned belt or pulley - Inspect and centering.
Improper blade balancing - Blades need balancing.

Blades scalping grass

Wrong cutting height - adjust cutting height.
Mower rollers not adjusted improperly - Check the wheel heights.
Low tire pressure - Check and inflate the tires.
Faster mower blade speeds - Blade speed required.
Blades are bent - Install new blades.

Uneven cutting results

Mower deck low - Level mower deck.
Low tire pressure - Inflate tires as required.
Incorrect wheel height - Adjust wheel heights correctly.
Ground speed too high - Need to reduce speed.
Blades worn - 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