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| Home / Skid Steer Loaders / John Deere Skid Steer Loaders / John Deere 125 |
John Deere 125 Troubleshooting
The
John Deere 125 skid steer loader is powered by Continental Y112 4-cylinder
gasoline engine with a rated power of 37 hp (27.3 kW), or Isuzu C190 4-cylinder
diesel engine with a rated power of 40 hp (29.6 kW). The John Deere 125 is
equipped with a radial-lift loader boom, single-speed hydrostatic transmission,
50/80 drive chains, and 10.00x16.5 standard tires. The hydraulic system has a
pump with fluid flow rate of 15 gpm (56.8 lpm). The diesel skid steer loader has
a rated operating capacity of 1410 lbs (640 kg) and tipping load of 2820 lbs
(1280 kg). The lift height is 108.3 inches (2750 mm) to hinge pin, and dump
height is 77.6 inches (1970 mm).
| Gasoline Engine Troubleshooting |
Engine starts hard or will not start
No gasoline in tank - Add fuel.
Incorrect fuel grade - Use quality fuel.
Clogged fuel system - Remove clogging.
Loose or disconnected spark plug wire - Check spark plug wiring connection, repair or change.
Spark plug is faulty - Spark plug need to be replaced.
Defective ignition system - Check ignition system and replace faulty parts.
Plugged fuel filter - Change fuel filter.
Dirty fuel lines - Clean fuel lines.
Fuel pump is damaged or dirty - Clean or replace fuel pump.
Carburetor is not adjusted - Check carburetor float adjustment.
Weak cylinder compression - Inspect cylinder block and change worn parts.
Engine runs irregularly
Ignition system is defective - Inspect ignition system and change failed components.
Air filter element is clogged - Clean or replace.
Faulty spark plug - Spark plug need to be replaced.
Clogged or defective fuel pump - Inspect fuel pump and change as required.
Valve clearance is not correct - Adjust to proper valve clearance.
Bad ignition timing - Ignition timing needs to be adjusted correctly.
Low idle speed setting is not correct - Test and adjust.
Engine starts but stalls suddenly
Spark plug is faulty - Spark plug need to be replaced.
Clogged or faulty carburetor - Repair or clean carburetor.
Ignition coil is defective - Ignition coil must be replaced.
Valve springs are broken or bad - Install new valve springs.
Valves are stuck - Valves must be cleaned.
Engine is overheated
Lack of engine oil - Check and refill engine oil.
Engine overloaded - Reduce engine load.
Too lean carburetor mixture - Adjust carburetor properly.
Bad ignition timing - Ignition timing needs to be adjusted correctly.
Valve setting is wrong - Adjust valves as required.
Radiator fins are clogged or radiator cap is faulty - Install new cap or clean radiator.
Insufficient coolant - Add coolant fluid and inspect the cooling system for leaks.
Thermostat is faulty - Replace thermostat.
Defective water pump - Change water pump as required.
Engine noise or knocking
Stale gasoline - Use proper fuel.
Engine is under excessive load - Reduce engine load.
Insufficient engine oil - Checking oil level and add if necessary.
Low idle speed set incorrectly - Correct idle settings.
Fuel pump is faulty or clogged - Check fuel pump and replace if necessary.
Crankshaft or main bearings wear - Replace crankshaft or bearings.
Incorrect valve clearance - Adjust valve clearance.
Worn piston rings or cylinder bore - Change defective components.
Engine power loss
Carburetor is clogged or incorrectly adjusted - Clean or correctly adjust carburetor.
Dirty air filter element - Replace or service air filter.
Fuel pump is dirty or defective - Clean or replace fuel pump.
Defective ignition system - Test ignition and replace failed parts.
Worn cylinder head gasket - Install new cylinder head gasket.
Stuck or burned valves - Clean or replace valves.
Cylinder block parts are damaged - Replace defective parts.
Clogged oil filter - Replace or service oil filter.
Engine using too much gasoline
Air filter is blocked - Change or clean air filter.
Improper adjustment of carburetor main jet - Adjust it properly.
Spark plug is loose or defective - Spark plug need to be replaced or tightened.
Wrong ignition timing - Set the ignition timing correctly.
Burned, worn, or stuck valves - Clean or replace valves.
Worn sleeve, piston, or rings - Change faulty components.
Incorrect valve clearance - Adjustment procedure required.
Low engine compression - Inspect cylinder block and change defective components.
Excessive engine oil consumption
Damaged gaskets or seals - Worn parts need to be replaced.
Valve stems or guides are damaged - Replace the valves.
Piston rings are stuck or broken - Change piston rings.
Scored piston or cylinder liner - Check piston and liner, install new parts as required.
Engine backfires
Carburetor fuel mixture is too lean - Adjust carburetor properly.
Clogged fuel lines - Fuel lines need to be cleaned.
Ignition timing is wrong - Set the ignition timing correctly.
Valve setting is incorrect - Adjust valves correctly.
Dirty air filter element - Change or clean air filter.
| Diesel Engine Troubleshooting |
Engine hard to start or won't start
Air in fuel tank - Bleed fuel tank.
Dirty fuel filter - Change filter element.
Faulty or dirty injection nozzles - Service or change injection nozzles.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is out of adjustment - Have it adjusted.
Defective fuel injection pump - Repair or install new pump.
Diesel starts and then shuts off
Dirty air filter - Change or service air filter element.
Fuel filter element clogging - Install new filter element.
Problems with fuel injection pump tightness - Inspect fuel injection pump for leaks.
Clogged or defective injectors - Inspect fuel injectors and change as required.
Defective fuel injection pump - Replacement or repair required.
Engine stalls after running
Low coolant temperature - Normalize the temperature by warming up the engine.
Fuel filter plugging - Install new filter element.
Air in the fuel pipes - Bleed the fuel pipes.
Damaged or dirty injection nozzles - Test injection nozzles and change if necessary.
Incorrect adjustment of fuel injection pump timing - Adjust according to specifications.
Engine stalling at idle
Low idle speed setting is not correct - Normalize low idle speed.
Fuel injection pump failure - Repair or install a new fuel pump.
Defective fuel injectors - Clean fuel injectors or change it.
Incorrect valve clearance - Adjust to proper valve clearance.
Engine power loss
Air filter is clogged - Install new air filter element.
Fuel injection nozzles are damaged - Install a new kit of correctly balanced nozzles.
Fuel injection pressure is wrong - Test fuel injection pressure and adjust it correctly.
Valve out of adjustment - Check and adjust.
Low idle speed adjustment is incorrect - Normalize low idle speed.
Restricted fuel hoses or lines - Clean fuel hoses and lines.
Cylinder head gasket is defective - Install new cylinder head gasket.
Piston rings are leaking or defective - Install new piston rings.
Engine is overheated
Lack of coolant in cooling system - Top up coolant fluid and check system for leaks.
Engine oil insufficient - Checking oil level and add if necessary.
Damaged radiator cap or dirty radiator core - Change cap or clean radiator.
Fan belt is worn or faulty - The fan belt needs to be replaced.
Engine overload - Load reducing required.
Low oil pressure
Low crankcase oil level - Fill the crankcase with oil.
Dirty oil filter element - Service or replace engine oil filter.
Improper type of engine oil - Fill up with the proper oil viscosity.
Crankshaft bearing oil clearance is incorrect - Bearings need to be reinstalled.
Oil pump is damaged - Repair or replace.
Engine noise or knocking
Engine oil level is low - Check oil level and add oil as required.
Engine is not fully warmed up - Warm up engine as required.
Wrong setting of fuel injection pump timing - Adjust according to specifications.
Low idle speed adjustment is incorrect - Need to adjust idle speed.
Defective fuel injectors - Replace fuel injectors.
Connecting rod is not aligned or defective - Align or replace connecting rod.
Worn or broken pistons - Install new pistons.
| Drive System Troubleshooting |
Drive system doesn't work in either direction
Low hydraulic oil level - Need to add oil.
Drive chain malfunction - Check drive chain and change faulty parts.
Relief valve is defective - Repair or replace relief valve.
Plugged suction line or hydraulic filter - Service suction line or replace hydraulic filter.
Faulty hand or foot controls - Replace or repair.
Drive motor or pump is defective - Check and repair if required.
Reduced power
Clogged hydraulic oil filter - Change or clean hydraulic filter.
Relief valve is open or defective - Close or replace relief valve.
Worn or faulty transmission components - Inspect and change faulty parts.
Defective input drive shaft - Rebuild or change the shaft.
There is air in the hydraulic system - Bleed hydraulic system.
Drive system overheating
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.
Hydraulic fluid filter is clogged - Change or clean hydraulic filter.
Worn or defective relief valve - Repair or install a new relief valve.
Drive pump or hydraulic motor malfunction - Repair or change faulty component.
Hydraulic oil cooler is dirty - Cooling fins should be cleaned.
Transmission overloading - Reduce loading.
Excessive noise
Incorrect oil viscosity - Use correct oil viscosity.
There is air in the hydraulic system - Bleed air from hydraulic system.
Drive pump or hydraulic motor is damaged - Repair or replace faulty component.
Defective or worn mechanical parts of drive system - Check drive system and change faulty parts.
| Hydraulics Troubleshooting |
Hydraulic system is overheated
Incorrect hydraulic pressure setting - Adjust pressure as required.
Faulty or improperly adjusted main relief valve - Adjust relief valve or change if required.
Hydraulic fluid is contaminated - Hydraulic fluid change required.
Hydraulic oil level is low - Add oil to the hydraulic system.
Worn hydraulic oil pump - Repair or install new hydraulic pump.
Boom does not raise or lower
Lift controls are defective - Repair or replace.
Hydraulic pump not working - Replace or repair pump if necessary.
Faulty hydraulic control valve - Repair or replace hydraulic valve.
Damaged hydraulic cylinder - Replace or repair boom cylinder.
Hydraulic fluid level low - Fill the system to proper hydraulic fluid level.
Bucket can't tilt
Bucket tilt controls are defective - Change or repair.
Defective hydraulic pump - Repair or replace pump if necessary.
Hydraulic control valve failure - Repair or replace the valve.
Hydraulic bucket cylinder is defective - Repair or change cylinder.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.
Slow boom or bucket operation
Hydraulic pump is worn - Flow-rate hydraulic pump and replace pump if necessary.
Hydraulic cylinder leaking - Cylinder seals need to be replaced.
Hydraulic fluid is insufficient - Checking hydraulic fluid level and add if necessary.
Faulty or incorrect setting hydraulic control valve - Repair or adjust properly.
Hydraulic system loosing pressure - Adjust it correctly.
Bucket or boom jerks when working
Air leaks in hydraulic system - Bleed hydraulic system.
Hydraulic oil filter element is clogged - Clean or replace the filter.
Dirty hydraulic oil - Hydraulic oil change required.
Cylinder tube or rod scoring - Change worn component.
Hydraulic pump is noisy
Hydraulic system leaking or not enough oil - Remedy hydraulic leakage or refill oil as necessary.
Clogged hydraulic filter - Clean or change the filter.
Suction line is clogged - Clean suction line as required.
Pump is sucking air - Remove air from hydraulics.
Pump components are worn out - Rebuild or replace hydraulic pump.
| Electrical Troubleshooting |
Battery cannot be charged
Electrical wire connections are corroded or loose - Clean or tighten wiring connections.
Battery terminal connectors are defective - Install new terminal connectors.
Faulty cell in battery - Use a new battery.
Belt is defective or loose - Adjust belt tension or replace belt.
Starter cranks slowly
Battery power is low - Battery needs to be recharged.
Battery is draining quickly - Service charging system or install new battery.
Disconnected wiring or bad battery terminals - Check wiring and clean or replace terminals.
Starter motor is not working
Battery is low or faulty - Recharge or change battery.
Battery cables are disconnected or improperly connected - Inspect cables and connect properly.
Battery voltage is low - Recharge the battery.
Faulty starter motor - Starter should be replaced.
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| SKID STEER LOADERS SPECIFICATIONS |