Specifications, Service and Repair of Farm and Lawn Tractors

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John Deere X748 Lawn Tractor Troubleshooting

John Deere X748 Diesel Engine Problems

Yanmar engine does not start

Incorrect fuel grade - Change fuel.
Dirt and debris in fuel system - Remove debris and dirt.
Fuel filter is clogged - Install new filter.
Brake pedal not depressed - Press the brake pedal.
Fuel injection pump is not working properly - Inspect and adjust.
Inspect starter cranking speed RPM. Compression problems.

Engine starts hard

Faulty spark plug - Test spark and change as required.
Diesel fuel pump is dirty - Wash, clean and adjust.
Clogged fuel lines - Clean the system carefully.
Old or improper fuel - Fill in proper gasoline.
Loose or corroded electrical connections - Inspect and change wires if required.
Starter is not working - Check the starter and replace defective components.

Engine runs unevenly

Plugged cooling fins - Clean and wash cooling fins.
Electrical contacts are damaged - Check and restore damaged connections.
Dirty fuel injectors - Clean and adjust.
Air cleaner element plugged - Change air cleaner.

Yanmar diesel engine overheats

Excessive engine load - Reduce loads.
Air intake screen plugged - Clean and wash dirty components.
Engine oil high or too low - Checking oil level and oil pressure.
Low quality engine oil - Change oil.
Check internal bearing clearance.
Idle speed problems - Adjusting fast idle speed.

Engine knocks

Engine overload - Reduce the load.
Low oil level - add oil as required.
Engine runs at low revs - Adjust the speed.
Cylinder bore and rings worn out - Replace damaged parts.
Check for engine overheating from plugged cooling fins.
Check and adjust valve clearance.

Engine does not develop full power

Engine temperature too high - Check air cleaner for plugged condition.
High engine oil - Remove excess oil.
Defective fuel pump - Check fuel pump and replace if required.
Faulty governor - Repair or replace governor.
Inspect and repair fuel injection pump.
Check engine compression.

John Deere X748 Electrical System Troubleshooting

Starter does not run

Blown fuse - Install new fuse.
Battery contacts are corroded - Clean contacts.
Low battery voltage - Charge the battery.
Starter fault - Repair or replace.
Electrical wires are damaged - Replace electric wires.

Battery doesn't charge

Battery cells fails - Fit new battery.
No contact between cable and battery terminal - Clean or change cable.

Lighting does not function

Light connector defective.
lamp does not work.
Wiring short circuit.

John Deere X748 Machine Problems

Excessive tractor vibration

Equipment drive belts worn out - Inspect and replace damaged belt.
Traction drive belt damage - Inspect and replace traction belt.
Drive sheaves are dirty - Change if necessary.
Cutting blade loose or unbalanced - Change as needed.

Machine does not move while engine is running

Parking brake is applied - Release the park brake.
Bypass valve lever activated - Disengage the bypass valve lever.
Blades loose - Tighten mower blades.
Unbalance in one or both blades - Check mower blade balancing.
Too little transmission oil - Check transmission oil lever.

John Deere X748 Lawnmower Problems

Clogged discharge chute

Lawn mower is driving too fast - Do not use high speed.
Grass has grown too long - Adjust cutting height.
Wet grass - Wait until the grass dries.
Low engine speeds - Adjust choke to full opening.
Airflow restriction - Adjust to high revs.
Lack of cutting height - Use higher cutting.
Belt installed incorrectly - Check belt installation.

Streaking of uncut grass

Mower deck clogged - Mower deck needs cleaning.
Damaged or worn blade - Sharpen the blade or install a new one.
Mower deck is low from ground - Leveling the mower deck.
Grass bag too full - Empty the grass bag.
Speed is very high - Choose recommended speed.

Slipping drive belt

Sheave is dirty - Pulley cleaning required.
Drive belt wear - Install new belt.
Belt tension problems - Check belt tension.

Excessive mower vibration

Debris in sheaves or on mower deck - Remove debris from the pulley or deck.
Worn belt or sheave - Change defective parts.
Belt or pulleys out of centering - Inspect and adjust.
Improper blade balancing - Balance blades properly.

Blade strips grass

Cutting height improper - adjust cutting height.
Mower wheels not adjusted correctly - Adjust rear or front wheel height.
Low tire inflation - Inflate tires as required.
Blades speed too fast - Blade speed required.
Bent blades during operation - Install new blades.

Uneven Cut

Deck level is too low - Level mower deck.
Low tire pressure - Need to inflate tires.
Incorrect rollers height - Adjust rear or front wheel height.
Ground speed too fast - Need to reduce speed.
Mower blade worn or bent - Installing new blade.

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JOHN DEERE LAWN TRACTORS SPECIFICATIONS

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ENGINES FOR JOHN DEERE LAWN TRACTORS

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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

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JOHN DEERE FRONT END LOADERS

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

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JOHN DEERE FARM TRACTORS SPECIFICATIONS

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