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Bobcat 751 Troubleshooting

The Bobcat 751 skid steer loader is powered by Peugeot XUD9 4-cylinder diesel engine with a rated power of 38 hp (28.4 kW) or Kubota V1903 4-cylinder diesel engine with a rated power of 35 hp (26.5 kW). The Bobcat 751 is equipped with a radial-lift loader boom, 1-speed hydrostatic transmission, 80HS drive chains, and 10.00x16.5 standard tires. The hydraulic system has a pump with fluid flow rate of 13 gpm (49.2 lpm). The hydraulic pressure is 2500 psi (172 bar). The skid steer loader has a rated operating capacity of 1200 lbs (545 kg) and tipping load of 2400 lbs (1090 kg). The lift height is 109.4" (2780 mm) to hinge pin, and dump height is 86.3" (2190 mm).

Engine Troubleshooting

Engine starts up hard or won't start
Air trapped in fuel system - Bleed air.
Dirty fuel filter - Change filter element.
Dirty or faulty injection nozzles - Check and replace nozzles if required.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is wrong - Have it adjusted.
Fuel injection pump is not working correctly - Change pump or rebuild it.

Engine starts but stops suddenly
Clogged air cleaner - Service or replace air cleaner.
Fuel filter element is dirty - Clean or replace the filter.
Fuel injection pump is leaking - Repair any leaks.
Dirty or defective injectors - Test and replace fuel injectors if necessary.
Fuel injection pump is damaged - Replace or repair injection pump.

Engine stalls after running
Engine is not warmed up to the required temperature - Warm up the engine.
Fuel filter element clogging - Install new filter element.
Air trapped in fuel system - Bleed air.
Fuel injection nozzles are clogged or faulty - Clean or replace injection nozzles.
Timing of fuel injection pump is incorrect - Set up as recommended.

Engine stops at idle
Incorrectly set low idle speed - Adjust as required.
Fuel injection pump is not operating properly - Repair or replace injection pump.
Dirty or defective injectors - Inspect fuel injectors and change as required.
Valve clearance is out of adjustment - Need to adjust valve clearance.

Lack of engine power
Air filter is plugged - Clean or replace element.
Fuel injection nozzles are faulty or clogged - Replace injection nozzles.
Incorrect fuel injection pressure - Adjust to correct pressure.
Valve clearance is out of adjustment - Need to adjust valve clearance.
Low idle speed setting is not correct - Correct low idle adjustment.
Restricted fuel hoses or lines - Clean fuel system lines and hoses.
Cylinder-head gasket is leaking - Replace the gasket as required.
Piston rings are worn or defective - Install new piston rings.

Engine overheating
Insufficient coolant fluid - Top up coolant fluid and check system for leaks.
Engine oil level is insufficient - Check oil level and add oil as required.
Defective radiator cap or clogged radiator fins - Clean radiator or replace cap.
Fan belt is worn or faulty - Belt replacement is recommended.
Engine is overloaded - Load reducing is recommended.

Insufficient oil pressure
Oil level is insufficient - Need to add oil.
Dirty oil filter - Service or change engine oil filter element.
Incorrect engine oil Use oil of correct viscosity.
Incorrect oil clearance in main bearing - Change bearings.
Oil pump failure - Remove and inspect oil pump.

Engine knocks or noises
Insufficient engine oil - Fill the crankcase with engine oil.
Low coolant temperature - Normalize the temperature by warming up the engine.
Timing of fuel injection pump is incorrect - Adjust according to specifications.
Wrong adjustment of low idle speed - Correct low idle settings.
Clogged or defective injectors - Replace fuel injectors.
Faulty or misaligned connecting rod - Need to change or align the connecting rod.
Broken or worn pistons - Replace the pistons as required.

Drive System Troubleshooting

Machine will not move in either direction or one direction
Hydraulic oil is insufficient - Fill the system to proper hydraulic oil level.
Worn drive chain - Inspect drive chain and replace defective parts.
Relief valve is stuck - Repair or replace.
Dirty hydraulic filter or suction line - Check, clean, or replace if required.
Faulty foot or hand controls - Change or repair.
Drive motor or pump is defective - Change or repair faulty component.

Reduced power
Hydraulic oil filter is clogged - Check, clean, or change as necessary.
Relief valve is opened or defective - Close or replace relief valve.
Worn or faulty transmission components - Inspect and change faulty parts.
Input drive shaft is stuck - Service or change faulty drive shaft.
Air trapped in hydraulic system - Need to bleed air.

Drive system keeps overheating
Hydraulic fluid level low - Fill up the hydraulic fluid.
Hydraulic fluid filter is dirty - Replace or clean hydraulic filter.
Stuck relief valve - Change or repair defective relief valve.
Hydraulic motor or drive pump failure - Repair or replace faulty component.
Hydraulic oil cooler is plugged - Clean the cooling fins.
Drive system is overloaded - Reduce loading.

Excessive noise
Incorrect oil viscosity - Use proper oil viscosity.
Air leaks in hydraulic system - Bleed air from hydraulic system.
Worn hydraulic motor or drive pump - Change or repair faulty component.
Mechanical parts of drive system are damaged or worn - Inspect the parts for worn or defect and repair as needed.

Hydraulics Troubleshooting

Hydraulic system is overheated
Incorrect hydraulic pressure setting - Adjust pressure as required.
Main relief valve failure or improper setting - Set up or change the relief valve.
Dirty hydraulic oil - The oil must be changed.
Not enough hydraulic oil in the system - Fill up the hydraulic oil.
Hydraulic pump is faulty - Repair or install new hydraulic pump.

Lift arm can't drop or lift
Lift controls failure - Check and repair as required.
Hydraulic pump not working - Repair or change pump if required.
Hydraulic control valve is defective - Repair or change hydraulic valve.
Broken hydraulic cylinder - Install a new boom cylinder or repair it.
Hydraulic oil is insufficient - Fill the system to proper hydraulic oil level.

Bucket is not working
Damaged bucket controls - Check and repair as required.
Hydraulic pump is broken - Replace or repair pump if necessary.
Hydraulic control valve failure - Install a new valve or repair it.
Damaged bucket cylinder - Replace or repair cylinder.
Hydraulic oil level low - Need to add oil.

Boom or bucket functions slowly
Faulty hydraulic oil pump - Check pump capacity and change if necessary.
Oil leaks from hydraulic cylinder - Replace cylinder piston seals.
Low hydraulic fluid level - Fill up the hydraulic fluid.
Hydraulic control valve is defective or set improper - Repair or adjust properly.
Hydraulic pressure is low - Set pressure correctly.

Lift arm or bucket is working jerkily
Air leaks in hydraulic system - Bleed air from system.
Dirty hydraulic oil filter element - Change or clean oil filter.
Hydraulic fluid is dirty - Hydraulic fluid change required.
Scored cylinder tube or rod - Replace damaged component.

Hydraulic pump is excessively noisy
Insufficient oil level or leaking hydraulic system - Refill hydraulic oil or repair leaks in system.
Plugged hydraulic filter - Service or replace hydraulic filter.
Suction line clogging - Service the suction line.
Air enters the pump - Air bleeding is required.
Damaged pump components - Rebuild or replace hydraulic pump.

Electrical Troubleshooting

Battery cannot be charged
Corroded or loose wire connections - Clean or tighten connections.
Defective battery terminal clamps - Terminal clamps need to be replaced.
Battery is defective - Replace the battery.
Worn or loose belt - Belt needs to be adjusted or changed.

Starter motor cranks slow
Battery power is low - Recharge the battery.
Battery is draining quickly - Service battery or change it.
Disconnected cables or faulty battery terminals - Connect wiring correctly or install new terminals.

Starter will not crank
Battery is low or faulty - Recharge or change battery.
Battery cables are disconnected or improperly connected - Inspect cables and connect properly.
Low battery power - Battery is drained, charge it.
Starter motor is damaged - Starter needs to be replaced.