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John Deere 90 Troubleshooting
The
John Deere 90 skid steer loader driveline system components: a 60 cu.in (1 L)
Onan NHC 4-cycle 2-cylinder horizontally opposed gasoline engine with a rated
power of 23 hp (17 kW), and 1-speed hydrostatic transmission. The hydraulic
system has a pump with a rated capacity of 7.5 gal/min (28.4 l/min). The system
relief pressure is 1750 psi (120 bar). The John Deere 90 is equipped with a
radial-lift loader boom, 60 drive chains, and 8.50x15 standard tires. The skid
steer loader has a maximum lift height of 98" (2490 mm) to hinge pin and dump
height of 73" (1855 mm). The rated operating capacity is 700 lbs (318 kg), and
tipping load is 1400 lbs (635 kg).
| Engine Troubleshooting |
Engine difficult to start or will not start
No gasoline in tank - Fill fuel up.
Incorrect fuel grade - Use quality fuel.
Fuel system clogged - Repair or replace.
Spark plug wire is loose or disconnected - Check the spark plug wire connection, repair or replace.
Spark plug is faulty - Change spark plug.
Clogged fuel filter - Replace fuel filter.
Faulty safety switch - Change damaged switch.
Carburetor not adjusted - Adjust according to instructions.
Low engine compression - Inspect cylinder block and change defective components.
Throttle cable is damaged or adjusted incorrectly - Adjust correctly or replace the cable.
Rough engine running
Clogged cooling fins - Need to clean or wash.
Ignition failure - Inspect ignition system and change failed components.
Defective or stuck throttle cable - Replace or clean the cable.
Air filter is blocked - Clean or change air filter.
Fuel pump is defective or dirty - Test fuel pump and replace if necessary.
Engine starts but stops suddenly
Damaged spark plug - Change spark plug.
Carburetor is defective or clogged - Replace or service carburetor.
Ignition coil is damaged - Install a new ignition coil.
Broken or loose valve springs - Replace valve springs.
Valves sticking - Clean the valves.
Engine overheating
Engine oil level is insufficient - Check oil level and add oil as required.
Excessive engine load - Load reducing required.
Cooling fins are blocked - Need to clean or wash.
Carburetor mixture is too lean - Set the carburetor correctly.
Incorrect ignition timing - Set the ignition timing properly.
Valve setting is incorrect - Adjust valves as required.
Engine knocking sound or abnormal noise
Stale fuel - Use proper gasoline.
Engine overloaded - Reduce the load.
Not enough engine oil - Fill up the engine oil.
Incorrectly adjusted low idle speed - Adjust idle speed.
Clogged or damaged fuel pump - Inspect fuel pump and change as required.
Crankshaft or main bearings are worn out - Change defective components as required.
Excessive valve clearance - Check and adjust.
Cylinder bore or piston rings are worn - Change faulty parts.
Loss of engine power
Carburetor is clogged or incorrectly adjusted - Adjust the carburetor properly or clean it.
Clogged air filter - Clean or change air filter.
Dirty or defective fuel pump - Service or change fuel pump.
Ignition failure - Inspect ignition system and change faulty parts.
Cylinder head gasket is defective - Replace cylinder head gasket.
Valves are stuck or burned - Replace or clean valves.
Damaged or worn push rod - Change push rod.
Cylinder block parts are faulty - Defective components need to be replaced.
Dirty oil filter element (if equipped) - Change or clean oil filter.
Engine using too much gasoline
Throttle did not open fully - Replace or adjust throttle cable.
Improper carburetor main jet adjustment - Adjust it properly.
Spark plug is faulty or loose - Tighten or change the spark plug.
Valves are worn, stuck, or burned - Change or service valves.
Worn sleeve, piston, or rings - Change faulty parts.
Incorrect valve clearance - Adjust valve clearance.
Engine oil consumption is too high
Defective seals or gaskets - Replace to repair leaks.
Valve guides or stems are damaged - Install new valves.
Seized or wear piston rings - Have piston rings replaced.
Piston or cylinder liner is damaged - Inspect liner and piston, fit new parts as necessary.
Blocked breather pipe or hose - Change or clean.
| Drive System Troubleshooting |
Drive system does not work in either direction
Low hydraulic fluid level - Fill the system to proper hydraulic fluid level.
Drive chain fault - Inspect drive chain and replace defective components.
Worn or defective relief valve - Change or repair defective relief valve.
Clogged suction line or hydraulic filter - Replace hydraulic filter or clean suction line.
Faulty hand or foot controls - Change or repair.
Defective drive pump or motor - Inspect and replace as necessary.
Low power
Plugged hydraulic oil filter - Change hydraulic filter.
Relief valve is open or defective - Close or replace relief valve.
Transmission parts are faulty or damaged - Inspect and replace defective parts.
Stuck input drive shaft - Repair or replace faulty drive shaft.
Air in hydraulic system - Bleed hydraulic system.
Drive system overheating
Insufficient hydraulic fluid - Add fluid as required.
Plugged hydraulic fluid filter - Replace hydraulic filter.
Relief valve is damaged or worn - Repair or replace.
Damaged drive pump or hydraulic motor - Inspect and change as required.
Hydraulic oil cooler is dirty - Clean cooling fins as required.
Drive system is overloaded - Load needs to be reduced.
Drive system is excessively noisy
Oil viscosity is too heavy - Use oil of proper viscosity.
Air in hydraulic system - Bleed hydraulic system.
Defective drive pump or hydraulic motor - Inspect and replace as necessary.
Mechanical components of drive system are damaged or worn - Check the parts for worn or defect and replace if required.
| Hydraulics Troubleshooting |
Hydraulic system overheats
Hydraulic pressure incorrectly adjusted - Adjust it correctly.
Defective or misadjusted main relief valve - Adjust relief valve or change if required.
Hydraulic oil contamination - The oil must be changed.
Not enough hydraulic oil in the system - Fill the hydraulic system with oil.
Worn hydraulic oil pump - Change or repair hydraulic pump if required.
Lift arm cannot be raised or lowered
Lift controls are defective - Change or repair.
Hydraulic pump failure - Change or repair hydraulic pump if required.
Hydraulic control valve is defective - Install a new hydraulic valve or repair it.
Hydraulic cylinder is faulty - Replace or repair boom cylinder.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.
Bucket can't tilt
Bucket controls failure - Change or repair.
Damaged hydraulic oil pump - Replace or repair pump if necessary.
Defective hydraulic control valve - Install a new hydraulic valve or repair it.
Damaged bucket cylinder - Repair or change cylinder.
Low hydraulic fluid level - Fill up the hydraulic fluid.
Boom or bucket functions slowly
Defective hydraulic pump - Flow-rate hydraulic pump and replace pump if necessary.
Leaking hydraulic cylinder - Correct leakage by changing the seals.
Hydraulic fluid level low - Add fluid as required.
Defective or not adjusted hydraulic control valve - Set properly or repair.
Hydraulic system loosing pressure - Adjust pressure correctly.
Jerky operation of the bucket or boom
Air trapped in hydraulic system - Air bleeding is required.
Hydraulic oil filter element clogging - Clean or replace the filter.
Dirty hydraulic fluid - Change hydraulic fluid.
Scored cylinder tube or rod - Replace worn component.
Hydraulic pump makes excessive noise
Hydraulic leakage or low oil level - Repair hydraulic leaks or add oil as required.
Plugged hydraulic filter - Clean or change the filter.
Dirty suction line - Suction line must be serviced.
Air trapped in hydraulic pump - Bleed air.
Damaged pump parts - Rebuild or replace hydraulic pump.
| Electrical Troubleshooting |
Battery won’t charge
Electrical cable connections are loose or corroded - Tighten or clean electrical wiring connections.
Defective battery terminal clamps - Change terminal clamps.
Faulty cell in battery - Change the battery.
Belt is damaged or loose - Belt needs to be adjusted or replaced.
Starter cranks slow
Low battery capacity - Battery is drained, recharge it.
Battery is not holding charge - Service or change the battery.
Bad terminals or disconnected battery cables - Check wiring and clean or replace terminals.
Starter is not working
Battery is drained or defective - Battery needs to be recharged or replaced.
Battery cables are disconnected or improperly connected - Inspect cables and connect properly.
Low battery output voltage - Low battery charging, charge as required.
Faulty starter motor - Starter should be replaced.
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| SKID STEER LOADERS SPECIFICATIONS |