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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.

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