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Bobcat S650 Troubleshooting

The Bobcat S650 skid steer loader driveline system components: a 203.2 cu.in (3.3L) Kubota V3307-DI-TE3 4-cylinder turbocharged liquid-cooled diesel engine with a rated power of 70.3 hp (52.4 kW), and 1-speed or 2-speed hydrostatic transmission. The hydraulic system has a pump with a rated capacity of 23 gal/min (87.1 l/min). The system pressure is 3550 psi (245 bar). The Bobcat S650 is equipped with hydraulic wet disc brakes and 12x16.5-12 tires. The skid steer loader has a max lift height of 124" (3150 mm) to hinge pin and dump height of 96.3" (2445 mm). The rated operating capacity is 2690 lbs (1220 kg), and tipping load is 5380 lbs (2440 kg).

Engine Troubleshooting

Engine difficult to start or doesn't start
Air in the fuel pipes - Bleed the fuel pipes.
Clogged fuel filter - Service or replace the filter.
Dirty or faulty injection nozzles - Clean or change injection nozzles.
Water in the fuel system - Change fuel and repair fuel system.
Valve out of adjustment - Adjust valve clearance.
Fuel injection pump is not working correctly - Rebuild or change fuel pump.

Engine starts and stops suddenly
Clogged air cleaner - Clean or replace element.
Clogged fuel filter - Change filter element.
Poor fuel injection pump tightness - Look for any leaks of fuel pump, tighten it fast.
Damaged or clogged injectors - Change or clean fuel injectors.
Faulty fuel injection pump - Replace or repair injection pump.

Diesel shuts off while driving
Engine not warmed up - Warm up the engine.
Fuel filter element clogging - Replace filter element.
There is air in the fuel system - Bleed the system.
Faulty fuel injection nozzles - Clean or change injection nozzles.
Incorrect adjustment of fuel injection pump timing - Adjust as recommended.

Engine stalls while idle
Incorrect low idle speed adjustment - Adjust as required.
Fuel injection pump is damaged - Replacement or repair required.
Dirty or defective injectors - Change or clean fuel injectors.
Excessive valve clearance - Adjust valve clearance according to specifications.

Low engine power
Air cleaner is dirty - Clean or change cleaner.
Fuel injection nozzles are faulty or clogged - Replace injection nozzles.
Fuel injection pressure is wrong - Correct the pressure settings.
Excessive valve clearance - Adjust to proper valve clearance.
Low idle speed setting is not correct - Need to adjust idle speed.
Dirty fuel lines or hoses - Service fuel lines and hoses.
Cylinder-head gasket is broken - Replace cylinder head gasket.
Worn or damaged piston rings - Replace piston rings.

Engine is overheated
Engine coolant is insufficient - Add coolant fluid and inspect the cooling system for leaks.
Insufficient engine oil - Fill up the oil to required level.
Dirty radiator core or faulty radiator cap - Replace cap or clean radiator.
Loose or damaged fan belt - If necessary, replace the belt.
Engine overload - Reduce engine load.

Oil pressure is insufficient
Low oil level - Fill crankcase to proper oil level.
Oil filter is clogged - Change or service engine oil filter.
Wrong oil viscosity - Fill up with the proper oil viscosity.
Crankshaft bearing has incorrect oil clearance - Change bearings.
Oil pump malfunction - Inspect and change as required.

Engine knocks or noises
Not enough engine oil - Check and refill engine oil.
Coolant temperature is low - Warm up to required temperature.
Timing of fuel injection pump is incorrect - Set the fuel pump timing correctly.
Wrong adjustment of low idle speed - Correct low idle settings.
Dirty or defective injectors - Change or clean fuel injectors.
Connecting rod is defective or not aligned - Need to replace or align the connecting rod.
Worn or scored pistons - Pistons replacement required.

Drive System Troubleshooting

Machine is not moving forward or backward
Insufficient hydraulic fluid - Add fluid as required.
Drive chain is worn - Check drive chain and change defective parts.
Input drive shaft malfunction - Repair or install a new drive shaft.
Relief valver is broken - Repair or install a new relief valve.
Clogged hydraulic filter or suction line - Service suction line or change hydraulic filter.
Defective or worn foot or hand controls - Replace or repair.
Damaged drive pump or motor - Change or repair faulty component.

Lack of power
Hydraulic oil filter is dirty - Replace hydraulic filter.
Open or damaged relief valve - Replace or close relief valve.
Transmission parts are worn or defective - Check and change faulty components.
Input drive shaft failure - Replace drive shaft.
Air leaks in hydraulic system - Bleed air from system.

Drive system keeps overheating
Hydraulic fluid is insufficient - Fill up the hydraulic fluid.
Dirty hydraulic fluid filter - Replace or clean hydraulic filter.
Defective or worn relief valve - Relief valve need to be replaced or repair.
Drive pump or hydraulic motor is damaged - Change or repair faulty component.
Hydraulic oil cooler is plugged - Cooling fins need to be cleaned.
Overloaded drive system - Reduce drive system load.

Drive system is excessively noisy
Oil viscosity is too heavy - Use oil of proper viscosity.
Air trapped in hydraulic system - Need to bleed air.
Damaged drive pump or hydraulic motor - Repair or change faulty component.
Mechanical parts of drive system are defective or worn - Check the components and replace if necessary.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure is not adjusted correctly - Adjust pressure as required.
Defective or misadjusted main relief valve - Replace or set up the relief valve.
Hydraulic fluid is dirty - Fill up with fresh hydraulic fluid.
Not enough hydraulic fluid in the system - Add fluid to the hydraulic system.
Defective hydraulic pump - Replace or repair pump if necessary.

Lift arm can't drop or lift
Faulty lift controls - Replace or repair.
Hydraulic pump failure - Replace or repair pump if necessary.
Hydraulic control valve is defective - Repair or replace the valve.
Hydraulic cylinder malfunction - Change or repair lift cylinder.
Hydraulic oil is insufficient - Fill the system to proper hydraulic oil level.

Bucket tilt does not work
Damaged bucket controls - Replace or repair.
Defective hydraulic pump - Repair or install new hydraulic pump.
Hydraulic control valve malfunction - Repair or replace the valve.
Hydraulic bucket cylinder is defective - Repair or change cylinder.
Hydraulic fluid is insufficient - Checking hydraulic fluid level and add if necessary.

Slow boom or bucket operation
Hydraulic pump is faulty - Check pump flow and change pump if necessary.
Oil leaks from hydraulic cylinder - Install new cylinder seals.
Low hydraulic fluid level - Checking hydraulic fluid level and add if necessary.
Damaged or incorrect adjusted hydraulic control valve - Adjust properly or repair.
Hydraulic pressure is low - Adjust it correctly.

Bucket or boom is jerky
Hydraulic system is leaking air - Air bleeding is required.
Dirty hydraulic oil filter - Replace or clean the filter.
Contaminated hydraulic oil - The oil must be changed.
Cylinder rod or tube is scratched - Replace worn component.

Hydraulic pump is noisy
Lack of oil or hydraulic leakage - Remedy hydraulic leakage or refill oil as necessary.
Dirty hydraulic filter - Change or clean oil filter.
Dirty suction line - Clean suction line as required.
Pump sucks air - Need to bleed air.
Pump components are faulty - Replace or rebuild the pump.

Electrical Troubleshooting

Battery will not charge
Loose or corroded wire connections - Service or tighten cable connections.
Faulty battery terminal connectors - Terminal connectors should be replaced.
Battery is defective - Battery replacement required.
Belt is defective or loose - Adjust belt tension or replace belt.

Starter cranks slow
Battery voltage is low - Low battery charging, charge as required.
Battery is not holding charge - Service charging system or replace battery.
Battery cables are disconnected or terminals are faulty - Connect wiring properly or install new terminals.

Starter will not work
Battery is drained or defective - Recharge or change battery.
Wire harness is disconnected or incorrectly connected - Check wire harness and connect as required.
Low battery power - Recharge the battery.
Starter motor failure - Repair or replace starter.