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Kubota M4900 Troubleshooting
The
Kubota M4900 utility tractor was manufactured between 2001 and 2008. The Kubota
M4900 driveline consists of Kubota F2803 five-cylinder indirect injection
naturaliy aspirated liquid-cooled diesel engine and 8x8 synchronized shuttle
transmission. A 167.6 cubic inches (2.7 L) engine has a cylinder bore of 3.43"
(87 mm), piston stroke of 3.64" (92 mm), and rated power of 54 hp (40.3 kW). The
maximum forward speed - 17.6 mph (28.3 km/h), maximum reverse speed - 5.1 mph
(8.2 km/h).
The open center hydraulic system includes a gear pump with rated fluid
flow of 10.9 gpm (41.6 lpm). The hydraulic system pressure is 195 bar
(2830 psi). The Kubota M4900 is equipped with a hydrostatic power
steering system, mechanical wet disc brakes, 6.50x16 (2WD) or 9.50x22
(4WD) front tyres, and 14.9x28 rear tyres. The wheelbase is 78.7" (1990
mm) for ROPS models and 81.7" (2070 mm) for Cab models. The tractor is
compatible with Kubota LA1002
front-end loader with a lift capacity to full height of 2579 lbs
(1169 kg) and breakout force of 3330 (1510 kg).
| Engine Troubleshooting |
| Engine will not start or starts up hard |
| Fuel filter clogging - Replace filter element |
| No fuel injection - Open fuel cock to inject fuel |
| Air in fuel pipes - Bleed fuel pipes |
| Fuel injectors are defective or dirty - Test fuel injectors and change if necessary |
| Fuel injection pump is not working correctly - Rebuild or replace pump |
| Low cylinder compression - Check and change damaged parts |
| Engine stops unexpectedly while running |
| Engine is cold - Warm up engine to required temperature |
| Air in fuel lines - Bleed fuel lines |
| Improper fuel injection - Fuel injection settings required |
| Fuel filter is dirty - Change the filter element |
| Faulty or dirty injectors - Service or change fuel injectors |
| Engine starts but immediately shuts off |
| Timing of fuel injection pump is wrong - Check and correct settings |
| Plugged fuel filter - Filter maintenance required |
| Fuel injector nozzles are damaged - Check and change nozzles as required |
| Fuel injection pump failure - Replace or repair injection pump |
| Air cleaner clogging - Service or replace the air cleaner |
| Engine stalls at low idle speed |
| Incorrectly set low idle speed - Correct the settings |
| Fuel injection pump is not operating properly - Repair or replace injection pump |
| Fuel injector nozzles are dirty or defective - Change or clean injector nozzles |
| The valve clearance is not adjusted - Adjust valve clearance |
| Lack of coolant in cooling system - Top up coolant fluid. Check and repair damage to the cooling system if required |
| Cooling system is dirty or cooling components are failed - Change faulty components or flush the cooling system |
| Engine oil level is insufficient - Fill up the engine oil |
| Broken fan belt or unadjusted belt tension - Adjust correctly or install new belt |
| Defective thermostat - Check and change if necessary |
| Clogged fuel injectors - Change fuel injectors |
| Incorrect fuel injection pressure - Check the fuel injection pressure and adjust if necessary |
| Dirty air filter - Service or change air filter |
| Oil filter is clogged - Replace or clean engine oil filter element |
| Engine is under excessive load - Reduce load or shift to lower gear |
| The valve clearance is not adjusted - Have it adjusted |
| Incorrect low idle speed adjustment - Correct low idle adjustment |
| Fuel hoses or pipes clogging - Service fuel pipes and hoses |
| Lack of compression: Leaking or faulty valves - Replace the valves |
| Abnormal engine noise or knocking |
| Unadjusted fuel injection pump timing - Adjust the fuel injection pump timing correctly |
| Fuel injector nozzles are damaged or dirty - Install new set of properly balanced nozzles |
| Insufficient engine oil - Fill the crankcase with engine oil |
| Engine not warmed up - Normalize the engine temperature |
| Crankshaft or main bearings failure - Need to install new components |
| Defective or broken piston rings - Replace piston rings |
| The flywheel to crankshaft bolts are loose - Tighten bolts as required |
| Oil leakage: Gaskets or seals can be faulty - Install new components |
| Crankcase oil too light - Use correct viscosity oil |
| Stuck or worn piston rings - Piston rings need to be replaced |
| Valve stems and guides are worn - Valves replacement required |
| Worn cylinder liners or pistons - Inspect liners and pistons, replace as necessary |
| Electrical System Troubleshooting |
| Battery cannot be charged |
| Battery is worn - Battery replacement required |
| Battery wiring harness failure - Inspect electrical cables for defects, repair or replace |
| Battery cables and terminals are loose or corroded - Terminals and cables need to be tightened or cleaned |
| Incorrect belt tension adjustment or worn belt - Change belt or correctly adjust belt tension |
| Battery voltage is low - Battery is drained, charge it |
| Battery is draining quickly - Service or replace the battery |
| Bad battery cable harness - Inspect cables for malfunctions, repair or change |
| Loose or corroded battery cables and terminals - Service or tighten battery terminals and cables |
| Low battery capacity - Recharge the battery |
| Drained or worn battery - Charge or replace the battery |
| Starter motor is damaged - Repair or change starter |
| Disconnected or incorrectly connected cables - Inspect battery cables and connect correctly |
| Transmission Troubleshooting |
| Difficulty shifting gears |
| Incorrectly adjusted or damaged clutch - Replace or adjust clutch |
| Loose or broken gear shift linkage - Change or repair shift linkage |
| Bent or worn shift forks - Replace defective shift forks |
| Gearshift mechanism is worn out - Repair or replace worn components if required |
| Low transmission pressure |
| Not enough oil in transmission - Check transmission oil level and add oil as required |
| Transmission fluid filter clogging (if fitted) - Change or clean the transmission fluid filter |
| Relief valve failure - Change the valve |
| Transmission is excessively noisy |
| Damaged or worn bearings - Replace the bearings |
| Low transmission oil level - Correct the transmission oil level |
| Transmission fluid contamination - Change transmission fluid |
| Worn gears or improper backlash - Replace gears or set backlash correctly |
| Bent or worn shift forks - Install new shift forks |
| Broken gaskets or seals - Install new gaskets or seal |
| Cracked transmission case - Install a new transmission case |
| Hydraulics Troubleshooting |
| Hydraulic system overheats |
| Hydraulic system pressure is not set correctly - Set the hydraulic pressure as required |
| Main relief valve incorrect adjustment or failure - Adjust relief valve or change if required |
| Hydraulic oil contamination - Change the oil |
| Air enters in hydraulic system - Inspect the pump seals, suction pipe, and fittings |
| Hydraulic oil pressure too low |
| Lack of hydraulic fluid - Fill the hydraulic system with oil |
| Hydraulic oil filter element clogging - Clean or change hydraulic filter |
| Hydraulic pump not working - Flow-rate pump and change pump if necessary |
| Hydraulic control valve block is not set properly or defective - Adjust correctly or change |
| Hydraulic cylinder is faulty - Check the hydraulic cylinder components for damage or wear and change if necessary |
| Hydraulic piping leaks - Detect leaks in the system and fix it |
| 3-point hitch does not raise or raises very slowly |
| Lack of hydraulic fluid - Check and refill the hydraulic fluid |
| Cold oil in hydraulic system - Wait for oil to warm up |
| Hydraulic oil filter element clogging - Clean or replace the hydraulic filter |
| Hydraulic pump is faulty - Test the pump performance and change pump if required |
| Unadjusted or defective main relief valve - Adjust or change relief valve |
| Hydraulic spool valve is not set properly or defective - Change or adjust correctly |
| Hydraulic cylinder malfunction - Check the hydraulic cylinder components for damage or wear and change if necessary |
| Damaged or loose hydraulic suction line - Tighten or change it |
| 3-point hitch lowers slowly or won't lower |
| Hydraulic spool valve is not set properly or defective - Adjust properly or replace |
| Hydraulic cylinder failure - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
| Lift arm shaft is damaged - Change the shaft |
| The hitch has any internal mechanical damage - Replace worn or defective hitch parts |
| Hitch is lowered or raised jerkily |
| Hydraulic system sucks air - Inspect the pump seals, suction pipe, and fittings |
| Hydraulic oil is dirty - Hydraulic oil change required |
| Hydraulic pump failure - Check pump flow and install new pump if necessary |
| Defective or incorrect setting hydraulic control valve block - Change or set correctly |
| Hydraulic cylinder is defective - Inspect the hydraulic cylinder parts for damage or wear and replace if required |
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| Farm Tractors Technical Specifications |
