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Kubota G1900 Troubleshooting

The Kubota G1900 garden tractor was manufactured from 1989 to 2000. The Kubota G1900 is powered by Kubota D722 vertical thee-cylinder indirect injection liquid-cooled diesel engine with a rated power of 18.8 Hp (14 kW) at 3800 rpm.

The engine has a Bosch MD mini fuel injection pump and forced lubrication by trochoid pump. The tractor is equipped with a hydrostatic transmission with travel speed control. The maximum travel speed (forward and reverse): 8.1 mph (13 km/h) / 3.7 (6 km/h).

The garden tractor was equipped with a hydrostatic steering system with 2-wheel steer (G1900) or 4-wheel steer (G1900S), 16x6.50-8 front tires, and 23x8.50-12 rear tires. The wheelbase is 51" (1290 mm). The Kubota G1900 is compatible with the following attachments: a 48" mid-mount 3-blade mower deck with cutting height of 1.4-3.5" (35-80 mm), 54", 60" mid-mount 3-blade mower decks with cutting height of 1.5-4.0" (38-102 mm), and 48" front blade.

Diesel Engine Troubleshooting
Engine won't start or difficult to start
Fuel filter is clogged - Replace filter element
No fuel injection - Open fuel cock to inject fuel
Air in fuel lines - Bleed fuel lines
Fuel injectors are clogged or faulty - Service or change fuel injectors
Fuel injection pump malfunctioning - Rebuild or replace pump
Poor engine compression - Inspect cylinder block and change worn parts
Engine shuts off unexpectedly during operation
Engine is not fully warmed up - Normalize the temperature by warming up the engine
Fuel lines leaking air - Tighten clamps, change faulty pipes
Irregular fuel injection - Adjust fuel injection timing
Plugged fuel filter - Change the filter element
Clogged or damaged injectors - Check fuel injectors and replace if required
Engine starts and stalls immediately
Fuel injection pump out of timing - Check and correct settings
Dirty fuel filter element - Install new filter element
Clogged or defective injector nozzles - Change injector nozzles
Fuel injection pump is damaged - Change pump or rebuild it
Dirty air cleaner element - Replace cleaner or install new cleaner element
Engine stops when idle
Incorrect low idle setting - Adjust low idling as recommended
Defective fuel injection pump - Change or repair the pump
Clogged or defective injector nozzles - Replace fuel injector nozzles
Improper valve clearance - Adjust valve clearance
Engine overheats
Lack of engine coolant - The cooling system needs to be refilled. Check for leaks or other malfunctions
Cooling system components are failed or system is clogged - Change faulty components or service cooling system
Engine oil level is low - Check oil level and add oil as required
Broken fan belt or unadjusted belt tension - Adjust correctly or replace the belt
Defective thermostat - Check and replace if required
Loss of engine power
Dirty or damaged injectors - Inspect fuel injectors and replace if necessary
Improper fuel injection pressure - Test fuel injection pressure and adjust it correctly
Dirty air filter - Change or replace air filter element
Oil filter is dirty - Replace or service engine oil filter
Diesel engine is overloaded - Change to lower gear or reduce load
Incorrect valve clearance - Adjust to proper valve clearance
Low idle speed setting is incorrect - Adjustment required
Fuel pipes or hoses clogging - Clean fuel system hoses and pipes
Low engine compression: Inlet or outlet valves are defective - Replace the valves
Abnormal engine knocking or noise
Fuel injection pump out of timing - Check the fuel injection pump timing setting
Fuel injector nozzles are damaged or dirty - Test injector nozzles and replace as required
Engine oil insufficient - Checking oil level and add if necessary
Engine is not fully warmed up - Warm up the engine to required temperature
Main bearings or crankshaft are worn out - Need to install new components
Piston rings are damaged or broken - Have piston rings replaced
Loose flywheel bolts - Inspect flywheel bolts and tighten properly
Excessive engine oil consumption
Oil leakage: Defective seals or gaskets - Replace to repair leaks
Incorrect oil viscosity - Use proper viscosity oil
Piston rings are stuck or worn - Change the piston rings as required
Worn valve stems and valve guides - Valves need to be changed
Cylinder liners or pistons are worn - Inspect pistons and liners, change as required

Hydrostatic Transmission Troubleshooting
Excessive HST transmission noise
Worn or out of adjustment speed control linkage - Change or adjust linkage
Transmission is under excessive load - Reduce the load is required
Dirty transmission fluid or insufficient fluid level - Fill to required level or change the fluid
Transmission components are damaged or worn - After disassembly and inspection, replace defective components
Hard shifting
Loose or broken shift linkage - Change defective linkage
Hydrostatic pump is faulty or seized - Change or repair pump
Transmission shift control parts are damaged or misadjusted - Adjust correctly or replace
Loss of power
Insufficient transmission fluid - Fill the transmission housing to proper fluid level
Defective or worn drive sheave - Change sheave
Shifter linkage is faulty or not adjusted - Change or adjust linkage
Bent or unadjusted speed control pedal linkage - Change or adjust linkage
Transmission leaking
Damaged transmission seals or gaskets - Replace gaskets or seals
Leaking final drive shaft - Change shaft seals
Cracked transmission case - Change broken case

Mower Deck Troubleshooting
Mower vibrates too much
Worn or dirty mower drive pulley - Service or change pulley
Drive belt is defective or loose - Change belt or adjust belt tension
Cutting blades are bent or unbalanced - Change or balance blades
Loose blade mounting bolts - Bolts should be tightened
Constant clogging of discharge chute
Fast ground speed - Use a lower speed
Tall grass - Use a lower cutting height
Engine is running at too low speed - Adjust carburetor to higher rpm
Cutting level is too low - Use a higher cutting height
Incorrect mower drive belt installation - Check drive belt for correct installation
Lawn mower leaving uncut grass
Discharge area is clogged - Need to clean the mower deck
Blades are not sharp - Need a blade sharpening
Damaged or worn blades - Replace the blades
High ground speed - Need to slow down
Cutting height is too low - Must be set to high cutting height
Filled bagger - Bagger must be empty
Blade scalped grass
Bumpy or not smooth lawn - Lawn needs to be leveled
Low cutting height - Change cutting height adjustment
High ground speed - Use a slower speed
Mower deck is not leveled properly - Adjust mower deck level properly
Blades are bent or worn - Blades need to be replaced
Tires are not properly inflated - Inflate tires correctly
Uneven cutting
Tires are not correctly inflated - Correct tire pressure
Incorrectly leveled mower deck - Level the deck properly
Not sharp blades - Need a blade sharpening
Bent or worn blades - Blades must be changed
Deck is plugged with grass - Clean out the mower deck
Damaged mower deck shell - Replace or repair the deck
Loose or faulty mower spindle - Spindle needs to be repaired or replaced

Electrical Troubleshooting
Battery is not charging
Electrical wire connections are corroded or loose Tighten or service cable connections
Defective battery terminal connectors - Terminal connectors need to be changed
Bad cell in battery - Install a new battery
Starter motor turns slow
Low battery power - Battery is drained, recharge it
Battery won’t hold charge - Battery needs service or replacement
Disconnected cables or faulty battery terminals - Check wiring connections and replace or clean terminals
Starter is not working
Battery is discharged or defective - Recharge or replace battery
Battery cables are disconnected or incorrectly connected - Check cables and connect as needed
Low battery output - Battery is drained, recharge it
Spark plug gapped improperly or faulty - Clean, gap or replace spark plug
Damaged starter motor or solenoid - Replace solenoid or repair starter



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