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Kubota G1800 Troubleshooting

The Kubota G1800 is a G-series garden tractor. This model was manufactured from 1989 to 2000. The G1800 driveline system components: Kubota D662 four-cycle vertical three cylinder diesel engine and shaft-driven hydrostatic transmission.

The max. forward speed - 8.1 mph (13 kph), a maximum reverse speed - 3.7 mph (6 kph). A 40.1 cu.in (0.66 L) engine output rating is 19.2 hp (14.3 kW) at 3800 rev/min. The compression ratio rating is 23:1. The Kubota G1800 garden tractor was equipped with 16x6.50-8 front tires and 23x8.50-12 rear tires.

The wheelbase is 50 inches (1270 mm). The tractor is compatible with the following attachments: a 48" mid-mount mower deck with cutting height of 1.4-3.5 in (35-80 mm), 54" mid-mount mower deck with cutting height of 1.5-4.0 in (38-102 mm), and 48" front blade.

Diesel Engine Troubleshooting
Engine won't start or starts hard
Dirty fuel filter element - Change filter element
No fuel supply from the tank - Open the fuel supply valve
Air in fuel pipes - Bleed fuel pipes
Fuel injectors are defective or dirty - Check fuel injectors and replace if required
Fuel injection pump is defective - Change or repair the pump
Engine has bad compression - Check and change damaged parts
Engine stops during operation
Engine not warmed up - Warm up the engine to required temperature
Fuel-line is leaking air - Retighten clamps, replace defective pipes
Improper fuel injection - Fuel injection settings required
Fuel filter is clogged - Change the filter element
Fuel injectors are defective or dirty - Service or change fuel injectors
Engine starts and immediately stalls
Timing of fuel injection pump is not adjusted - Correct injection timing
Plugged fuel filter - Clean the filter element
Fuel injector nozzles are damaged or dirty - Install a new set of well-balanced nozzles
Faulty fuel injection pump - Replacement or repair required
Dirty air cleaner - Clean or replace the air cleaner element
Engine stalls when idling
Wrong adjustment of low idle speed - Correct low idle settings
Fuel injection pump is not working correctly - Repair or replace injection pump
Fuel injector nozzles are clogged or faulty - Change or clean injector nozzles
Valve clearance is not correct - Have it adjusted
Engine overheating
Insufficient coolant - Add the coolant. Check radiator and hoses for leaks
Cooling system is clogged or cooling parts are defective - Replace faulty parts or service cooling system
Insufficient engine oil - Check and refill engine oil
Fan belt is worn or belt tension is improper - Change or adjust belt tension correctly
Thermostat is defective - Test thermostat opening temperature, replace as required
Engine power loss
Clogged fuel injectors - Service or change fuel injectors
Incorrect fuel injection pressure - Adjust to proper pressure
Air filter element is dirty - Replace or service air filter element
Clogged oil filter - Replace or clean engine oil filter element
Engine overload - Shift to lower gear or reduce the load
Valve clearance is out of adjustment - Need to adjust valve clearance
Incorrect low idle speed adjustment - Adjust as required
Restricted fuel pipes or hoses - Service fuel pipes and hoses
Engine losing compression: Intake or exhaust valves are damaged - Valves need to be replaced
Engine noise or knocking
Fuel injection pump timing is incorrect - Repair or replace fuel injection pump
Damaged or clogged injector nozzles - Change or clean injector nozzles
Not enough engine oil - Fill up the engine oil
Engine not warmed up - Warm up engine as required
Crankshaft or main bearings failure - Change defective components as required
Stuck or worn piston rings - Replace piston rings
The flywheel to crankshaft bolts are loose - Tighten bolts as required
Diesel engine consuming too much oil
Oil leaks: Seals or gaskets are defective - Replace worn parts to avoid leaks
Oil viscosity is wrong - Use oil of proper viscosity
Damaged or seized piston rings - Piston rings need to be replaced
Damaged valve guides or valve stems - Replace the valves
Damaged cylinder liners or pistons - Check pistons and liners, install new parts as required

Hydrostatic Transmission Troubleshooting
HST transmission makes noise
Worn or unadjusted speed control linkage - Adjust or repair linkage
Excessive transmission load - Reduce transmission load
Dirty transmission fluid or insufficient fluid level - Add fluid to the correct level or fill transmission with fresh fluid
Transmission components are damaged or worn - Replace or repair defective components
Difficult shifting
Shift linkage is rusty or worn - Lubricate or replace the linkage
Blocked or faulty hydrostatic pump - Repair or replace pump
Transmission shift control components are worn or unadjusted - Adjust properly or change
Power is too low
Transmission fluid insufficient - Check and refill the transmission fluid
Drive sheave is defective or worn - Install a new sheave
Shifter linkage is faulty or not adjusted - Adjust correctly or replace linkage
Defective or not adjusted speed control pedal linkage - Adjust or repair linkage
Transmission leaks
Transmission gaskets or seals are worn - Replace seals or gaskets
Final drive shaft leakage - Install new shaft seals
Transmission case is cracked - Change broken case

Mower Deck Troubleshooting
Excessive mower vibration
Mower deck drive sheave is clogged or worn - Replace or service sheave
Loose or worn drive belt - Install a new belt or adjust belt tension
Cutting blades are not balanced or warped - Balance or replace blades
Blade bolts are not tightened well - Bolts need to be tightened
Constant clogging of discharge chute
Fast ground speed - Select a slower speed
Grass is too long - Must be set to low cutting height
Low engine speeds - Adjust carburetor to higher rpm
Cutting height is too low - Adjust mower to higher cutting height
Mower drive belt installation is improper - Check drive belt for correct installation
Uncut grass when mowing
Clogged mower deck - Need to clean the mower deck
Blades are not sharp - Sharpen the blades
Damaged or worn blades - Blades must be changed
High mowing speed - Need to slow down
Mower cuts too low - Change cutting height adjustment
Filled grass bag - Clean grass bag
Blades scalping grass
Uneven or bumpy lawn - Level the lawn
Cutting height is too low - Raise the cutting height
High mowing speed - Select a lower speed
Deck is not leveled correctly - Adjust the level of mower deck correctly
Blades are bent or worn - Install new blades
Low tire pressure - Need to inflate tires
Mower cuts uneven
Incorrect tire pressure - Inflate tires as required
Incorrect level of mower deck - Deck needs to be adjusted properly
Blades are too dull - Blades need to be sharpened
Blades are defective or worn - Blades need to be replaced
Clogged mower deck - Mower deck needs to be cleaned
Broken mower deck shell - Replace or repair the deck
Mower spindle is faulty or loose - Replace or repair the spindle

Electrical Troubleshooting
Battery does not charge
Electrical wire connections are loose or corroded - Tighten or service connections
Battery terminal clamps are faulty - Change terminal clamps
Worn-out battery - Use a new battery
Starter motor cranks slow
Low battery output voltage - Recharge the battery
Battery does not hold charge - Battery needs service or replacement
Wires are disconnected or battery terminals are corroded - Check cables and clean or change terminals
Starter doesn't crank
Battery is drained or defective - Charge or change the battery
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly
Low battery power - Battery is drained, recharge it
Incorrectly gapped or worn spark plug - Clean, gap or replace spark plug
Solenoid or starter motor failure - Change solenoid or repair starter



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