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Gehl 4615 Troubleshooting

The Gehl SL 4615 skid steer loader is powered by 121.7 cu.in (2.0L) Perkins 104-19 KF 4-cylinder liquid-cooled diesel engine with a rated power of 41 hp (30.6 kW) at 2800 rpm. The Gehl SL 4615 is equipped with a radial-lift boom, single-speed hydrostatic transmission, 80H drive chains, and 10.00x16.5 or 31x13.5x15 tires. The hydraulic system has a pump with fluid flow rate of 16 gpm (60.6 lpm) or 32 gpm (121.3 lpm). The hydraulic pressure is 2800 psi (193 bar). The skid steer has a rated operating capacity of 1225 lbs (556 kg) and tipping load of 2450 lbs (1112 kg). The lift height is 114.5" (2910 mm) to hinge pin, and dump reach at full height is 18" (455 mm).

Engine Troubleshooting

Diesel hard to start or doesn't start
Air in fuel tank - Bleed fuel tank.
Fuel filter element is dirty - Install new filter element.
Faulty or dirty injection nozzles - If necessary, replace with a new nozzle.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve out of adjustment - Adjust valve clearance.
Fuel injection pump malfunction - Replace or repair injection pump.

Diesel starts and stops
Air filter is dirty - Clean or change filter.
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.
Fuel injection pump is damaged - Replace or rebuild injection pump.

Engine stops running suddenly
Engine not warmed up - Warm up the engine.
Fuel filter plugging - Replace filter element.
Air in fuel tank - Bleed fuel tank.
Clogged or burnt injection nozzle - Replace injection nozzles.
Timing of fuel injection pump is incorrect - Adjust the pump as required.

Engine stalling at idle
Low idle speed set incorrectly - Need to adjust idle speed.
Fuel injection pump failure - Rebuild or replace pump.
Clogged or defective injectors - Replace fuel injectors.
Valve clearance is not correct - Check and adjust as required.

Loss of engine power
Air cleaner is clogged - Clean or change.
Defective or clogged injection nozzle - Clean or change injection nozzles.
Fuel injection pressure is wrong - Adjust to correct pressure.
Valve clearance is wrong - Correct valve clearance.
Improperly adjusted low idle speed - Adjustment required.
Fuel hoses or lines are clogged - Clean fuel system lines and hoses.
Leaking cylinder head gasket - Replace the gasket as required.
Worn or damaged piston rings - Install new piston rings.

Engine overheating
Coolant level is low - Refill to the correct level and inspect system for leaks.
Engine oil level is low - Check oil level and add oil as required.
Defective radiator cap or clogged radiator fins - Change cap or clean radiator.
Loose or defective fan belt - Replace the fan belt.
Diesel engine overloaded - Reduce engine load.

Oil pressure too low
Low crankcase oil level - Fill crankcase to proper oil level.
Dirty oil filter element - Service or replace engine oil filter.
Oil grade or viscosity is wrong - Use oil of correct viscosity.
Incorrect crankshaft bearing oil clearance - Bearing replacement required.
Defective oil pump - Install a new pump.

Engine knocks or noises
Engine oil insufficient - Need to add engine oil.
Engine is not preheated - Warm up the engine.
Improper fuel injection timing - Adjust fuel injection pump as required.
Incorrectly set low idle speed - Adjustment required.
Fuel injector fault - Replace or clean fuel injectors.
Misaligned or faulty connecting rod - Align or change connecting rod.
Worn or broken pistons - Pistons replacement required.

Drive System Troubleshooting

Machine will not move in either direction or one direction
Low hydraulic fluid level - Checking hydraulic fluid level and add if necessary.
Worn drive chain - Inspect drive chain and replace defective components.
Worn or defective relief valve - Rebuild or install a new relief valve.
Hydraulic filter or suction line is dirty - Check, clean, or change if necessary.
Defective or worn foot or hand controls - Replace or repair.
Drive pump or motor is damaged - Check and repair if required.

Reduced power
Hydraulic oil filter is clogged - Replace or service hydraulic filter.
Relief valve is damaged or open - Change or close relief valve.
Defective or worn transmission parts - Check and change defective components.
Damaged input drive shaft - Replace drive shaft.
Hydraulic system is leaking air - Bleed air from hydraulic system.

Drive system overheats
Insufficient hydraulic fluid - Check and refill the hydraulic fluid.
Hydraulic fluid filter is clogged - Replace hydraulic filter.
Relief valve is damaged or worn - Relief valve need to be replaced or repair.
Damaged drive pump or hydraulic motor - Repair or replace faulty component.
Plugged hydraulic oil cooler - Cooling fins should be cleaned.
Overloaded drive system - Load should be reduced.

Drive system is noisy
Incorrect oil viscosity - Use proper oil viscosity.
Hydraulic system is leaking air - Air bleeding is required.
Damaged drive pump or hydraulic motor - Inspect and change as required.
Defective or worn mechanical parts of drive system - Inspect the parts for worn or defect and repair as needed.

Hydraulics Troubleshooting

Hydraulic system overheats
Hydraulic pressure is not adjusted correctly - Adjust it correctly.
Unadjusted or defective main relief valve - Adjust relief valve or change if required.
Dirty hydraulic fluid - Fill up with fresh hydraulic fluid.
Lack of hydraulic fluid - Need to add fluid.
Hydraulic pump is worn - Repair or replace pump if necessary.

Lift arm does not lower or raise
Lift controls failure - Check and repair as required.
Hydraulic pump malfunction - Repair or install new hydraulic pump.
Faulty hydraulic control valve - Install a new hydraulic valve or repair it.
Broken hydraulic cylinder - Change or repair lift cylinder.
Hydraulic oil is insufficient - Need to add oil.

Bucket does not tilt
Damaged bucket controls - Replace or repair.
Hydraulic pump failure - Repair or install new hydraulic pump.
Hydraulic control valve malfunction - Replace or repair the valve.
Faulty hydraulic bucket cylinder - Change or repair cylinder.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.

Bucket or lift arm functions slowly
Worn hydraulic oil pump - Check pump performance and change it if necessary.
Oil leaks from hydraulic cylinder - Replace cylinder piston seals.
Low hydraulic fluid level - Add fluid as required.
Hydraulic control valve is unadjusted or worn - Adjust properly or repair.
Hydraulic pressure is low - Correct adjustment is required.

Lift arm or bucket is moving jerkily
There is air in the hydraulic system - Air bleeding is required.
Hydraulic oil filter element is clogged - Replace or clean the filter.
Hydraulic oil contamination - Change hydraulic oil.
Scored cylinder tube or rod - Replace defective component.

Hydraulic pump makes excessive noise
Low oil level or hydraulic leaks - Remedy hydraulic leakage or refill oil as necessary.
Plugged hydraulic filter - Service or replace hydraulic filter.
Clogged suction line - Suction line must be serviced.
Air enters the pump - Remove air from hydraulics.
Pump components are worn out - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery is not charging
Loose or corroded wire connections - Service or tighten cable connections.
Defective electrical terminal connectors - Terminal connectors need to be changed.
Battery failing - Battery replacement required.
Belt is loose or defective - Need to adjust belt tension or replace belt.

Starter turns slow
Low battery output voltage - Battery is drained, charge it.
Battery won’t hold charge - Service charging system or change battery.
Bad terminals or disconnected battery cables - Connect wiring correctly or install new terminals.

Starter does not work
Battery is discharged or worn - Charge or replace the battery.
Wiring harness is disconnected or improperly connected - Check wiring harness and connect as required.
Low battery voltage - Battery is drained, recharge it.
Defective starter motor - Starter should be replaced.