Home / Farm Tractors / Kubota Tractors / Kubota L4150

Kubota L4150 Troubleshooting

The Kubota L4150 is a L-series compact utility tractor. This model was manufactured from 1984 to 1990. The tractor was designed in 2 versions: L4150F (2WD) and L4150DT (4WD). The Kubota L4150 is equipped with a 141.9 cu.in (2.3L) Kubota F2302-DI 4-cycle 5-cylinder naturally aspirated liquid cooled diesel engine with a rated power of 50 hp (37.3 kW).

The transmission includes a single dry type clutch and partially synchronized gearbox with 8 forward and 8 reverse gears. Max forward speed - 15.4 mph (24.8 km/h), maximum reverse speed - 15.2 mph (24.5 km/h).

The open center hydraulic system includes a gear pump with a rated capacity of 9 gallons per minute (34.1 liters per minute). The main relief pressure is 172.5 bar (2500 psi). The 2-wheel drive models are equipped with 6.50x16 front tires and 14.9x28 rear tires. The 9.50x20 front tires and 14.9x28 rear tires are used for tractors with 4-wheel drive. The wheel base is 76.4" (1940 mm). The tractor is compatible with a Kubota BF900 loader with maximum lift height of 111.4" (2820 mm), and Kubota L4540 backhoe with digging depth of 123" (3120 mm).

Engine Troubleshooting
Engine doesn't start or difficult to start
Fuel filter is dirty - Clean or replace the filter
The fuel shut-off valve is closed - Open fuel shut-off valve
There is air in the fuel system - Bleed the system
Fuel injectors are clogged or faulty - Change fuel injectors
Fuel injection pump failure - Replace or rebuild injection pump
Engine has bad compression - Check cylinder block and change worn components
Engine shuts off unexpectedly during operation
Low coolant temperature - Warm up the engine
Air in fuel system - Air-bleed fuel system
Improper fuel injection - Fuel injection settings required
Plugged fuel filter - Replace filter element
Clogged or damaged injectors - Clean or replace fuel injectors
Diesel starts and stalls suddenly
Timing of fuel injection pump is not adjusted - Check and correct adjustments
Fuel filter is dirty - Change filter element
Damaged or clogged injector nozzles - Install a new set of well-balanced nozzles
Fuel injection pump is not operating properly - Change or repair the pump
Clogged air cleaner - Change or replace air cleaner element
Engine stops when idle
Incorrectly set low idle speed - Adjust low idling as recommended
Faulty fuel injection pump - Repair or install new pump
Damaged or clogged injector nozzles - Service or replace nozzles if required
The valve clearance is incorrect - Adjust to proper valve clearance
Engine overheats
Engine coolant is insufficient - The cooling system needs to be refilled. Any leaks must be repaired
Cooling system components are failed or system is clogged - Change faulty components or service cooling system
Engine oil insufficient - Fill the crankcase with engine oil
Improper fan belt tension or damaged belt - Adjust correctly or install new belt
Defective thermostat - Test thermostat opening temperature, replace as required
Reduced engine power
Fuel injectors are damaged or dirty - Check fuel injectors and replace if required
Incorrect fuel injection pressure - Adjust to correct pressure
Clogged air filter - Air filter maintenance required
Clogged oil filter element - Change or clean engine oil filter element
Engine is under excessive load - Reduce load or shift to lower gear
Incorrect valve clearance - Correct valve clearance
Low idle speed setting is not correct - Correct low idle adjustment
Clogged fuel pipes or hoses - Service fuel pipes and hoses
Loss of compression: Worn or damaged valves - Change the valves
Abnormal engine knocking or noise
Fuel injection pump out of timing - Adjust injection timing
Clogged or damaged injector nozzles - Replace fuel injector nozzles
Insufficient engine oil - Checking oil level and add if necessary
Engine not warmed up - Warm up the engine as required
Crankshaft or main bearings are worn out - Replace crankshaft or bearings
Piston rings failure - Have piston rings replaced
Flywheel screws are loose - Tighten the screws firmly
Diesel engine consuming too much oil
Oil leakage: Damaged gaskets or seals - Defective components must be replaced
Incorrect oil viscosity - Use correct viscosity oil
Piston rings are defective or worn - Piston rings need to be replaced
Valve stems and guides are worn - Replace the valves
Damaged pistons or cylinder liners - Check pistons and liners, install new parts as required

Electrical System Troubleshooting
Battery cannot be charged
Faulty cell in battery - Battery change required
Damaged battery wiring harness - Inspect wiring for damage, replace or repair
Battery cables and terminals are loose or corroded - Tighten or service terminals and cables
Belt slipping or wrong belt tension adjustment - Replace belt or properly adjust belt tension
Starter motor turns slow
Low battery capacity - Recharge the battery
Battery drains quickly - Service charging system or install new battery
Battery cable harness damage - Check battery cables for damage, change or repair
Loose or corroded terminals and cables - Clean or tighten cables and terminals
Starter motor is not working
Low battery power - Battery is drained, recharge it
Drained or defective battery - Recharge or change battery
Starter motor is damaged - Change or repair starter
Wiring harness is disconnected or improperly connected - Check wiring harness and reconnect properly

Transmission Troubleshooting
Gears are hard to shift
Incorrectly adjusted or damaged clutch - Clutch replacement or adjustment required
Stuck or damaged gear shift linkage - Change defective shift linkage
Worn or damaged shift forks - Install new shift forks
Gearshift mechanism is worn out - Repair or replace worn components if required
Transmission oil pressure is insufficient
Fluid level is low - Check transmission fluid level and add it as required
Transmission fluid filter element is dirty (if fitted) - Replace or clean transmission fluid filter
Relief valve is faulty - Replace valve as required
Transmission noises
Broken or worn bearings - Bearings replacement required
Insufficient fluid supply - Add transmission fluid as required
Transmission fluid contamination - Fill up with fresh transmission fluid
Damaged gears or improper backlash - Set backlash properly or change the gears
Shift forks are worn or damaged - Shift forks need to be replaced
Transmission fluid leaks
Gaskets or seals are defective Change defective seal or gaskets
Cracked transmission housing - Housing needs to be replaced

Hydraulics Troubleshooting
Hydraulic system is too hot
Incorrect hydraulic pressure adjustments - Adjust correctly
Faulty or incorrectly adjusted main relief valve - Replace or set up the relief valve
Contaminated hydraulic oil - Change hydraulic oil
Air trapped in the hydraulic system - Check the pump seals, suction line, and fittings
Hydraulic oil pressure is low
Hydraulic fluid level is low - Check and refill the hydraulic fluid
Hydraulic oil filter element is dirty - Clean the hydraulic filter element or replace if necessary
Hydraulic pump malfunction - Check pump flow and install new pump if necessary
Damaged or incorrect adjusted hydraulic spool valve - Replace or adjust properly
Hydraulic cylinder is defective - Check cylinder components for damage or wear and change if necessary
Leakage in hydraulic lines - Find leaks in hydraulic system and repair it
3-point hitch lifts too slowly or can't lift
Hydraulic oil level is low - Fill the hydraulic system with oil
Cold hydraulic oil - Warm up the oil
Hydraulic fluid filter element clogging - Change the hydraulic filter element or service if required
Hydraulic pump not working - Check the pump performance and replace it if required
Unadjusted or defective main relief valve - Set up or change the relief valve
Hydraulic control valve is not set properly or defective - Change or set correctly
Hydraulic cylinder is not working - Check cylinder components for damage or wear and change if necessary
Suction pipe is broken or loose - Tighten the pipe or replace it
Three-point hitch dropping is too slow or cannot be dropped
Hydraulic spool valve block is not set properly or defective - Replace or adjust properly
Faulty hydraulic cylinder - Inspect the hydraulic cylinder parts for damage or wear and replace if required
Hitch cross shaft is damaged - Replace the shaft
The hitch is defective if there is internal mechanical damage - Change defective or worn hitch parts
Hitch jerks when drop or lift
Air enters in hydraulic system - Check the pump seals, suction line, and fittings
Hydraulic fluid is contaminated - Fill up with new hydraulic fluid
Faulty hydraulic oil pump - Check the pump performance and replace it if required
Hydraulic control valve is not set properly or defective - Change or adjust correctly
Hydraulic cylinder is not working - Inspect cylinder parts for wear or damage and replace if required

Steering System Troubleshooting
Steering is hard
Defective or improperly assembled steering column - Reassemble properly or change steering column
Air trapped in the steering system - Bleed air from system
Incorrect toe-in adjustment - Adjust toe-in correctly
Tires are incorrectly inflated - Inflate as required
Steering pump not working - Repair or replace steering pump
Worn or damaged power steering valve assembly - Replace or repair steering valve as required
Faulty steering box components - Repair power steering box
Lack of steering fluid - Need to add steering oil
Steering system oil leak - Retighten steering hose and pipe connections
Steering wheel has too much free-play
Steering column shaft or coupling has maximum wear - Change defective part
Worn or damaged power steering valve assembly - Repair or replace the steering valve
Worn steering box components - Change defective steering box components
Faulty steering pump - Check the hydraulic steering pump and change if necessary
Steering linkage or tie-rod ends are worn - Change failed part
Front wheels wander to right or left
Tires are incorrectly inflated - Inflate as required
Not adjusted toe-in - Adjust toe-in correctly
Faulty or worn steering linkage or tie-rod ends - Replace damaged part
Worn steering box components - Replace defective components of power steering box
Power steering valve assembly is worn or defective - Check and replace as required
Front hub bearings are damaged or incorrectly adjusted - Change or adjust bearings correctly



Farm Tractors Technical Specifications
JD 1026R JD 3650 JD 6400 JD 7810
FORD 1320 FORD 2810 FORD 3930 FORD 5600
MF 250 MF 690 MF 3060 MF 6180
NH TC48DA NH M100 NH T7550 NH 8560
CASE IH 495 CASE IH 1255XL CASE IH 2140 CASE IH 2294