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Husqvarna YTH20K46 Troubleshooting

The Husqvarna YTH20K46 is a two-wheel drive lawn tractor with cast iron front axle. This model was manufactured between 2009 and 2010.

The Husqvarna YTH20K46 driveline includes a 36.4 cu.in (597 cc) Kohler Courage SV600 four-cycle single-cylinder vertical shaft air-cooled gasoline engine and Tuff Torq K46 belt-driven hydrostatic transmission with foot-controlled variable speed drive. The engine has a cylinder bore of 3.7" (94 mm), piston stroke of 3.38" (86 mm), and rated power of 20 hp (14.9 kW).

The maximum forward speed - 5.2 mph (8.4 km/h), max. reverse speed - 2.9 mph (4.7 km/h). The Husqvarna YTH20K46 fitted with 15x6.00-6 front tires and 18x8.50-10 rear tires. The wheel base is 48" (1220 mm). The lawn tractor is equipped with a 46" mid-mount 3-blade side discharge mower deck with cutting height of 1.5-4.5" (37-115 mm), 6 cut positions, and mechanical lifting.

Engine Troubleshooting
Engine is not starting or hard starting
No fuel in fuel tank - Add fuel
Low-quality gasoline - Change fuel
Water or air in fuel system - Remove air or water from system
Disconnected or loose spark plug wire - Check the spark plug wire connection, repair or replace
Spark plug is faulty - Replace spark plug
Dirty fuel filter - Replace fuel filter
Safety contact for brake pedal defective - Install new part
Carburetor is not adjusted - Check carburetor float adjustment
Poor cylinder compression - Check cylinder block and change worn parts
Damaged or incorrectly adjusted choke cable - Adjust properly or change the cable
Irregular engine running
Cooling fins are blocked - Clean and wash as required
Defective ignition - Inspect ignition system and change failed components
Stuck or faulty choke cable - Change or clean the cable
Plugged air filter - Clean or change air filter
Dirty or defective fuel pump - Inspect fuel pump and change as required
Engine starts but immediately stops
Spark plug is defective - Install new spark plug
Dirty or defective carburetor - Clean or change carburetor
Ignition coil is damaged - Change ignition coil as required
Damaged or weak valve springs - Valve springs need to be changed
Valves sticking - Service the valves
Engine overheated
Insufficient engine oil - Check and refill engine oil
Engine is under excessive load - Load reducing required
Air intake grill is clogged - Clean and wash as required
Too lean carburetor mixture - Adjust carburetor properly
Ignition timing is wrong - Ignition timing needs to be adjusted correctly
Valve setting is wrong - Adjust valves as required
Engine knocking sound or abnormal noise
Low octane gasoline - Use proper fuel
Engine overloaded - Reduce engine load
Lack of engine oil - Add oil to the engine crankcase
Low idle speed setting is incorrect - Need to 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
Valve clearance is not correct - Need to adjust valve clearance
Damaged cylinder bore or piston rings - Replace defective parts
Low engine power
Improperly adjusted or dirty carburetor - Adjust the carburetor properly or clean it
Air filter is dirty - Change or service air filter
Dirty or damaged fuel pump - Service or change fuel pump
Ignition system failure - Check ignition and replace faulty components
Cylinder head gasket is worn - Install new head gasket
Burned or stuck valves - Service or change valves
Push rod is worn or defective - Change push rod
Worn cylinder block components - Change defective parts
Engine uses too much fuel
Throttle opening is not full - Adjust or change throttle cable
Improper adjustment of carburetor main jet - Adjust the carburetor main jet properly
Defective or loose spark plug - Re-tighten or change the spark plug
Stuck, burned, or worn valves - Replace or service valves
Worn rings, piston, or sleeve - Replace defective components
Incorrect valve clearance - Need to adjust valve clearance
High engine oil consumption
Gaskets or seals may be damaged - Replace worn parts to avoid leaks
Worn valve stems and valve guides - Valves must be replaced
Worn or broken piston rings - Piston rings need to be replaced
Cylinder liner or piston is scuffed - Check liner and piston, change as required
Breather pipe or hose is clogged - Replace or clean

Hydrostatic Transmission Troubleshooting
Hydrostatic transmission is excessively noisy
Speed control pedal linkage is bent or not adjusted - Adjust or change linkage
Excessive loading - Reduce loading
Dirty transmission fluid or insufficient fluid level - Top up to proper level or change transmission fluid
Transmission components are damaged or worn - Check internal transmission parts for damage or wear and replace if required
Hard shifting
Corroded or worn shift linkage - Lubricate or change linkage
Worn or seized hydrostatic pump - Change or repair pump
Transmission shift control components are worn or unadjusted - Adjust properly or change
Power is too low
Lack of transmission oil supply - Fill the transmission housing with oil
Worn or damaged drive sheave - Change sheave
Shifting linkage is misadjusted or broken - Adjust correctly or replace linkage
Speed control linkage is defective or unadjusted - Change or adjust linkage
Transmission leaks
Transmission gaskets or seals are damaged - Seals and gaskets need to be replaced
Final drive shaft leaks - Shaft seals need to be changed
Cracked transmission case - Install a new transmission case

Mower Deck Troubleshooting
Mower vibrates too much
Mower deck drive sheave is clogged or worn - Service or change sheave
Damaged or loose drive belt - Adjust belt tension or replace belt
Not balanced or bent mower blades - Balance or replace blades
Loose blade mounting bolts - Tighten it fast
Constant clogging of discharge chute
Fast ground speed - Select a lower speed
Long grass - Use a lower cutting height
Reduced engine speeds - Choke is not fully opening
Low cutting height - Change cutting height adjustment
Mower deck drive belt installed incorrectly - Install drive belt as required
Lawn mower leaving uncut grass
Discharge area is clogged - Clean out the mower deck
Blades are not sharp - Need to sharpen the blades
Blades are defective or worn - Replace the blades
Fast mowing speed - Need to slow down
Cutting height is too low - Use a higher cutting height
Bagger is overfilled - Bagger must be empty
Blades are scalping the grass
Bumpy or unleveled lawn - Level the lawn
Low cutting height - Raise the cutting height
High ground speed - Need to slow down
Incorrect level of mower deck - Adjust the level of mower deck correctly
Worn or bent blades - Change the blades
Incorrect tire pressure - Inflate tires correctly
Mower deck to cut unevenly
Tire pressure is too low - Correct tire pressure
Improperly leveled mower deck - Level the deck correctly
Blades are not sharp - Need a blade sharpening
Blades are worn or damaged - Install new blades
Discharge area is clogged - Check cutting deck and clean as necessary
Deck shell is damaged - Rebuild or change mower deck
Mower spindle is faulty or loose - Replace or repair the spindle

Electrical Troubleshooting
Battery won’t charge
Loose or corroded electrical wiring connections - Clean or tighten wiring connections
Faulty electrical terminal connectors - Change terminal connectors
Battery dead cell - Install a new battery
Starter turning slow
Battery power is low - Charge the battery
Battery runs out quickly - Service charging system or change battery
Wires are disconnected or battery terminals are corroded - Connect cables correctly or replace terminals
Starter motor won't turn
Battery is low or faulty - Recharge or replace battery
Battery wiring is disconnected or improperly connected - Inspect wiring and connect as required
Low battery capacity - Charge the battery
Spark plug dirty or improperly gapped - Clean, gap or replace spark plug
Starter motor or solenoid is defective - Starter/solenoid needs to be replaced



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