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John Deere 1250 Troubleshooting

The John Deere 1250 is a 2WD or 4WD compact utility tractor. This model was manufactured by Yanmar built from 1982 to 1989. The John Deere 1250 driveline components: a 142.7 cu.in (2.3L) Yanmar 3T95 4-cycle 3-cylinder direct injection liquid-cooled diesel engine and 9x3 sliding gear transmission.

The engine has a cylinder bore of 3.74" (95 mm), piston stroke of 4.33" (110 mm), and rated power of 44 hp (32.8 kW). Max. travel speed (forward and reverse): 15.4 mph (24.8 km/h) / 7.9 mph (12.7 km/h). The open center hydraulic system includes a gear pump with a rated fluid flow of 11.2 gal/min (42.4 l/min).

The 3-point hitch has a lift capacity of 2240 lbs (1016 kg) at 24" (600 mm) behind pin. The wheel base is 80.7" (2040 mm) for 2-wheel drive models and 78" (1980 mm) for 4-wheel drive models. The JD 1250 tractor is compatible with John Deere 100 loader with a maximum lift height of 93.5" (2370 mm) and lift capacity to full height of 1760 lbs (798 kg).

Engine Troubleshooting
Engine will not start or starts up hard
Fuel filter is dirty - Install new filter element
No fuel supply from the tank - Open the fuel supply valve
Air in fuel pipes - Bleed fuel pipes
Faulty or dirty injectors - Service or change fuel injectors
Fuel injection pump malfunctioning - Replace or repair injection pump
Bad cylinder compression - Inspect cylinder block and change defective components
Engine stops unexpectedly while running
Low coolant temperature - Warm up the engine
Fuel lines leaking air - Tighten clamps, change faulty pipes
Improper fuel injection - Fuel injection settings required
Fuel filter is clogged - Clean the filter or install new filter element
Dirty or damaged injectors - Clean or replace fuel injectors
Engine starts and immediately stops
Incorrectly set fuel injection pump timing - Adjust the fuel injection pump timing correctly
Dirty fuel filter element - Install new filter element
Clogged or defective injector nozzles - Change injector nozzles
Fuel injection pump is defective - Replace or rebuild injection pump
Air cleaner element clogging - Change or replace air cleaner element
Engine stops while idle
Incorrectly adjusted low idle speed - Correct low idle adjustment
Defective fuel injection pump - Change or repair the pump
Fuel injector nozzles are dirty or defective - Service or replace nozzles if required
Valve clearance is wrong - Check and adjust as required
Engine overheats
Insufficient coolant - Fill the radiator to the required level. Check for leaks or other malfunctions
Cooling system components are worn or system is clogged - Change faulty components or service cooling system
Engine oil level low - Fill the crankcase with engine oil
Broken fan belt or incorrect belt tension - Adjust properly or replace the belt
Defective thermostat - Replace the thermostat
Engine power is insufficient
Clogged or damaged injectors - Test fuel injectors and change if necessary
Incorrect fuel injection pressure - Adjust to proper pressure
Air filter clogging - Install new filter element or replace it
Clogged oil filter - Change or clean engine oil filter element
Diesel engine is overloaded - Reduce the load or use a lower gear
The valve clearance is not adjusted - Adjust valve clearance
Low idle speed set incorrectly - Need to adjust idle speed
Fuel pipes or hoses are dirty - Service fuel hoses and pipes
Engine losing compression: Valves are broken or leaking - Replace the valves
Abnormal engine knocking or noise
Unadjusted fuel injection pump timing - Adjust injection timing
Fuel injector nozzles fault - Service or replace nozzles if required
Engine oil level low - Need to add engine oil
Engine is not fully warmed up - Warm up engine as required
Crankshaft or main bearings are worn out - Worn parts replacement required
Piston rings are defective or broken - Have piston rings replaced
Loose flywheel screws - Check the flywheel screws and tighten as required
High engine oil consumption
External oil leaks: Damaged seals or gaskets - To repair leaks, replace worn parts
Incorrect oil viscosity - Use proper viscosity oil
Piston rings are defective or worn - Replace piston rings
Damaged valve guides or valve stems - Valves must be replaced
Worn cylinder liners or pistons - Check liners and pistons, install new components as required

Electrical System Troubleshooting
Battery will not charge
Battery is defective - Use a new battery
Battery wiring harness failure - Inspect electrical cables for defects, repair or replace
Loose or corroded terminals and cables - Cables and terminals must be tightened or cleaned
Incorrect belt tension adjustment or worn belt - Replace belt or properly adjust belt tension
Starter motor cranks slow
Low battery output voltage - Battery is drained, recharge it
Battery is draining quickly - Service charging system or change battery
Damaged battery cable harness - Check electrical cables for damage, repair or replace
Battery cables and terminals are loose or corroded - Tighten or service cables and terminals
Starter doesn't crank
Low battery output voltage - Charge the battery
Discharged or faulty battery - Charge or replace the battery
Starter motor is damaged - Change or repair starter
Improperly connected or disconnected wiring harness - Inspect wiring harness and connect properly

Transmission Troubleshooting
Hard shifts
Worn or misadjusted clutch - Clutch replacement or adjustment required
Loose or broken gear shift linkage - Replace or repair the shift linkage
Worn or damaged shift forks - Shift forks need to be changed
Defective gearshift mechanism - Replace defective components
Transmission oil pressure is low
Oil level is insufficient - Fill the transmission housing to proper oil level
Transmission fluid filter is plugged (if fitted) - Clean or replace the transmission fluid filter
Relief valve is faulty - Change relief valve
Transmission makes excessive noise
Damaged or worn bearings - Bearings need to be replaced
Insufficient fluid supply - Fill system with correct transmission fluid level
Contaminated transmission fluid - Fill up with fresh transmission fluid
Gears are defective or backlash is incorrect - Change worn gears or set backlash correctly
Worn or damaged shift forks - Change defective shift forks
External oil leaks
Worn gaskets or seals - Seals and gaskets replacement required
Transmission case is cracked - Replace case or transmission assembly

Hydraulics Troubleshooting
Hydraulic system is too hot
The system pressure has not been corrected - Make the correct settings
Main relief valve is damaged or adjusted improperly - Adjust or change relief valve
Dirty hydraulic oil - The oil must be changed
Aeration in hydraulic system - Check the pump seals, suction pipe, and fittings
Hydraulic fluid pressure is insufficient
Lack of hydraulic fluid - Check and refill the hydraulic fluid
Hydraulic oil filter element is dirty - Replace filter element or clean if required
Defective hydraulic pump - Flow-rate pump and change pump if necessary
Hydraulic control valve is faulty or out of adjustment - Adjust correctly or replace
Hydraulic cylinder malfunction - Inspect cylinder components for wear or damage and change if required
Leakage in hydraulic lines - Find leaks in hydraulic system and repair it
Three-point hitch lifting is too slow or cannot be lifted
Hydraulic oil level is low - Check oil level and add hydraulic oil as required
Hydraulic fluid is too cold - Allow fluid to warm
Hydraulic fluid filter clogging - Service the hydraulic filter or change if required
Defective hydraulic pump - Test pump flow rate and replace pump if required
Main relief valve is damaged or adjusted improperly - Set up or change the relief valve
Damaged or incorrect adjusted hydraulic control valve - Change or set correctly
Faulty hydraulic cylinder - Inspect cylinder parts for wear or damage and replace if required
Loose or damaged suction line - Tighten or replace
Hitch can't drop or drops too slowly
Faulty or incorrect setting hydraulic spool valve - Set correctly or replace
Hydraulic cylinder malfunction - Check the hydraulic cylinder parts for damage or wear and replace if necessary
Damaged hitch cross shaft - Change the shaft
Mechanical parts of the hitch are damaged - Change damaged or worn hitch components
Three-point hitch raises or lowers not smoothly
Hydraulic system sucks air - Inspect the suction pipe, fittings, and pump seals
Contaminated hydraulic fluid - Change hydraulic fluid
Damaged hydraulic oil pump - Flow-rate pump and change pump if necessary
Defective or incorrect setting hydraulic control valve block - Adjust correctly or change
Defective hydraulic cylinder - Check cylinder parts for wear or damage and replace if necessary

Steering System Troubleshooting
Steering is difficult
Steering column is broken or improperly installed - Steering column must be installed properly or replaced
Aeration in steering system - Bleed the system of air
Improper toe-in adjustment - Check toe-in and correct
Tires are improperly inflated - Inflate as necessary
Steering pump is faulty - Repair or replace steering pump
Worn or damaged power steering valve - Repair or change the steering valve
Worn steering gear box parts - Change defective steering gear box components
Insufficient steering oil - Need to add steering oil
Steering system oil leakage - Retighten the connections of the hydraulic steering lines and hoses
Excessive free play of steering wheel
Steering column shaft or coupling is worn out - Change faulty part
Steering valve is defective or worn - Change or repair steering valve if required
Damaged steering gear box parts - Defective power steering box components must be replaced
Steering pump is worn - Steering pump needs to be repaired or replaced
Steering tie-rod ends or linkage are worn - Change damaged component
Tractor pulls to left or right
Tires are not correctly inflated - Inflate tires as necessary
Incorrect toe-in adjustment - Adjust toe-in correctly
Steering tie-rod ends or linkage are defective - Replace damaged component
Faulty steering gear box components - Defective parts of power steering gearbox must be replaced
Faulty or worn power steering valve - Change or repair steering valve if required
Front hub bearings are defective or improperly adjusted - Change or adjust bearings correctly




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