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John Deere L108 Tractor Problems

Gasoline Engine Troubleshooting

John Deere L108 tractor engine doesn't start

No gasoline in tank - Add gasoline.
Improper fuel grade - Change gasoline.
Old gasoline - Drain fuel and add fresh.
Dirt and debris in fuel system - Remove debris and dirt.
Spark plug defective - Inspect and replace if required.
Spark plug not working - Inspect ignition spark.
Dirty fuel filter - Install new filter.
Brake pedal not pushed down - Push the brake pedal down.
Carburetor is not adjusted - Check carburetor float adjustment.
Check and adjust governor linkage. Compression problems.

Gas engine long starting

Faulty spark plug - Test spark and change as required.
Carburetor settings incorrect - Adjusting as required.
Clogged fuel lines - Service required.
Choke cable not adjusted properly - Checking and adjusting.
Old or incorrect fuel - Pour quality fuel.
Electrical connections are damaged - Checking and replace wiring if necessary.
Starter fault - Check starter, repair or replace.

Rough running engine

Plugged cooling fins - Remove dirt from cooling fins.
Electrical contacts are damaged - Check and replace damaged connections.
Incorrect ignition settings - Check ignition and adjust if necessary.
Throttle cable sticks - Check and repair.
Air cleaner element plugged - Replace air cleaner.

JD L108 Engine stops or misses

Faulty spark plug - Test spark plug.
Carburetor defective or not adjusted - Repair or adjust.
Ignition coil defective - Test ignition coil and replace if necessary.

Engine overheating

Excessive engine load - Reduce loads.
Air intake screen clogged - Clean dirty components.
Too little or too much oil - Checking oil level and oil pressure.
Improper engine oil viscosity - Change engine oil.
Inspect crankshaft to main bearing clearance.
Idle speed problems - Adjusting fast idle speed.

Engine doesn't idle speed

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

Engine knocks

Stale gasoline - Use proper gasoline.
Excessive engine load - Reduce loads.
Lack of engine oil - add oil as required.
Engine speed too low - Adjust the required speed.
Piston rings and cylinder bore worn - Inspect cylinder bore or rings for worn.
Inspect for engine overheats from clogged cooling fins.
Check and adjust valve clearance.
Checking for wear crankshaft or camshaft bearings.

John Deere L108 Engine back-fire

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

Loss of power

Engine temperature too high - Replace air cleaner.
Overfilling engine oil - Remove excess oil.
Fuel pump broken - Testing fuel pump output.
Governor problems - Inspect and repair governor.
Check and overhaul carburetor.
Check engine compression.

Excessive Fuel Consumption

Choke doesn't open well - Replace throttle cable.
Incorrect carburetor adjustment - Adjust or repair carburetor.

Exhaust with black smoke

Air filter is dirty or oil soaked - Clean or change filter.
Throttle not fully engaged - Inspecting and adjusting choke.
Check and adjust carburetor float level.

JD L108 Electrical Troubleshooting

Starter does not run

Main fuse malfunction - Installing new fuse.
Poor terminal connection - Clean connections.
Battery discharged - Charge the battery.
Ignition switch is damaged - Installing new lock.
Faulty starter - Repair or replace.
Wiring damage - Reconnect wires.

Battery will not charge

Battery cells defective - Install new battery.
Bad contact between battery pole and cable - Change or clean cable.

Lights do not work

Light plug defective.
Replace the lamps.
Inspect electrical wires for short- circuit.

John Deere L108 Machine Problems

Excessive tractor vibration

Implements driven belt damaged or worn - Check and change worn belt.
Traction drive belt damage - Installing new driven belt.
Drive sheaves malfunction - Clean or replace.
The mower deck blades are bent or unbalanced - Change damaged blades.

Tractor doesn't move when engine runs

Parking brake is applied - Release the park brake.
Bypass valve pulled out - Disengage the bypass valve lever.
Mower blades are loose - Tighten mower blades.
Improper blade balance - Check blade balancing.
Low transmission oil - Fill transmission with oil.

JD L108 Lawnmower Problems

Discharge Chute Clogged

Lawn mower is driving too fast - Do not use high speed.
High grass - Use a shorter cutting height.
Grass too wet - Don't mow while wet grass.
Low engine speeds - Adjust throttle to full opening.
Lack of air flow - Adjust to high revs.
Cutting too low - Choose the correct cutting height.
Belt fitted incorrectly - Reinstall the belt properly.

Uncut grass during operation

Mower deck clogged - Check cutting deck and clean if necessary.
Damaged blade - Inspect and fit new blade if required.
Deck too low - Deck leveling required.
Grass bag too full - Clean bagger.
Speed is very high - Operate the mower at low speed.

Belt Slipping

Debris in pulleys - Clean or replace.
Belt is worn out - Fit new belt.
Belt tension is incorrect - Adjust belt tension.

John Deere L108 Mower vibrates

Mower deck clogged or in sheaves - Clean sheave and deck from clogging.
Damaged mower belt or pulleys - Replace defective parts.
Pulley or belt out of alignment - Check and adjust.
Blades out of balance - Blade balance required.

Blade strips grass

Cutting height improper - adjust cutting height.
Mower rollers height wrong - Check wheel adjustment.
Low tire pressure - Inflate tires as required.
Blades speed too fast - Adjust the blade speed.
Blades are bent - Replace blades.

Uneven Cut

Mower deck low - Checking and adjust deck height.
Insufficient tire pressure - Check and inflate the tires.
Wrong rollers position - Check wheel adjustment.
Traveling too fast - Don't use fast speed.
Blades blunt - Inspect and fit new blade if required.

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