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Husqvarna CTH135 Troubleshooting

The Husqvarna CTH 135 lawn tractor was manufactured between 2002 and 2003. The components of Husqvarna CTH135 powerline system: a 30.5 cu.in (500 cc) Briggs and Stratton 31G777 Intek 4-cycle single cylinder OHV vertical shaft air-cooled gasoline engine with a rated power of 17.5 hp (13 kW), and Hydro-Gear 321-0510 belt-driven hydrostatic transmission with infinite forward and reverse gears.

The engine has a float-feed carburetor, pulse type fuel pump, lubrication with oil pump and filter, and air cleaner with dual element. The maximum travel speed (forward/reverse): 5 mph (8 km/h) and 2.4 mph (3.8 km/h). The Husqvarna CTH 135 is equipped with a manual steering system, disc brakes, 15x6.00-6 front tires, and 18x8.50-8 rear tires. The wheelbase is 46.9" (1190 mm).

The tractor is compatible with a 36" mid-mount 2-blade side discharge mower deck with cutting height of 1.5-4.0 in (38-102 mm), 6 cut positions, manual blade engagement, and mechanical lift system.

Engine Troubleshooting
Engine doesn't start or starts hard
Empty fuel tank - Fill gasoline up
Low-quality gasoline - Use quality gasoline
There is air in the fuel system - Bleed the system
Spark plug wire is disconnected or loose - Inspect spark plug wiring connection, change or repair
Spark plug is faulty - Install new spark plug
Clogged fuel filter - Change fuel filter
Safety contact for brake pedal defective - Install new part
Carburetor is not adjusted - Check carburetor float adjustment
Engine has low compression - Check cylinder block and replace defective parts
Not adjusted or damaged throttle cable - Replace cable or adjust correctly
Engine runs intermittently
Air intake screen is plugged - Wash or clean as required
Ignition system problems - Inspect ignition system and change failed components
Throttle cable is stuck or defective - Change or clean the cable
Plugged air filter - Replace or service air filter
Fuel pump is defective or dirty - Clean or install new fuel pump
Engine starts and then stalls
Damaged spark plug - Spark plug need to be replaced
Faulty or clogged carburetor - Service or change carburetor
Ignition coil is defective - Change ignition coil as required
Broken or loose valve springs - New valve springs need to be installed
Stuck valves - Valves need to be cleaned
Engine is overheated
Engine oil level is low - Need to add engine oil
Engine is under excessive load - Reduce engine load
Cooling fins are clogged - Clean and wash as required
Carburetor is running lean - Set the carburetor properly
Improper ignition timing - Adjust ignition timing as required
Valve setting is improper - Set the valves properly
Abnormal engine noise or knocking
Stale fuel - Change gasoline
Engine overloaded - Reduce engine load
Engine oil insufficient - Check and refill engine oil
Incorrectly adjusted low idle speed - Correct the settings
Clogged or damaged fuel pump - Service or change fuel pump
Worn main bearings or crankshaft - Repair or replace defective parts
Valve clearance is incorrect - Need to adjust valve clearance
Piston rings or cylinder bore are damaged - Replace defective parts
Low engine power
Dirty or improperly adjusted carburetor - Service or properly adjust carburetor
Air filter element is plugged - Service or change air filter
Fuel pump is clogged or faulty - Clean or replace fuel pump
Ignition system malfunction - Inspect ignition system and change failed components
Cylinder head gasket is worn - Install new head gasket
Valves are stuck or burned - Service or replace valves
Push rod is worn or damaged - Replace push rod
Cylinder block components are faulty - Replace defective parts as required
Engine uses too much fuel
Choke doesn't open well - Adjust or replace choke cable
Incorrect adjustment of carburetor main jet - Adjust the carburetor main jet correctly
Spark plug is loose or faulty - Tighten or replace spark plug
Worn, stuck, or burned valves - Clean or change valves
Sleeve, piston, or rings are damaged - Replace faulty parts as required
Incorrect valve clearance - Adjust valve clearance according to specifications
Engine consuming too much oil
Defective seals or gaskets - New components need to be installed
Valve stems and guides are worn - Valves replacement required
Piston rings are stuck or broken - Change piston rings
Worn cylinder liner or piston - Inspect liner and piston, replace as necessary
Clogged breather pipe or hose - Change or service

Hydrostatic Transmission Troubleshooting
HST transmission makes excessive noise
Speed control linkage is worn or unadjusted - Replace or adjust linkage
Transmission overload - The load should be reduced
Dirty transmission fluid or insufficient fluid level - Add fluid to the correct level or fill the transmission with fresh fluid
Transmission parts are worm or defective - After disassembling and inspection, change defective components
Difficult shifting
Shift linkage is damaged or loose - Replace or service the linkage
Hydrostatic pump is defective or blocked - Replace or repair pump
Worn or misadjusted transmission shift control parts - Adjust correctly or replace
Low power
Insufficient transmission oil - Fill the transmission housing with oil
Worn or damaged drive sheave - Change sheave
Misadjusted or faulty shifting linkage - Adjust correctly or change linkage
Defective or not adjusted speed control pedal linkage - Adjust or install new linkage
Transmission leaking
Transmission seals or gaskets are broken - Seals and gaskets need to be replaced
Final drive shaft is leaking - Install new shaft seals
Transmission case is cracked - Replace case or transmission assembly

Mower Deck Troubleshooting
Excessive mower vibration
Mower deck drive sheave is clogged or worn - Clean or replace sheave
Loose or defective drive belt - Adjust belt tension or replace belt
Mower blades are bent or out of balance - Balance or replace blades
Loose blade mounting bolts - Tighten it fast
Discharge chute regular clogging
High mowing speed - Operate at slower speed
Grass is too high - Use a lower cutting height
Engine runs at low revs - Choke is not fully opening
Low cutting height - Use a higher cutting height
Incorrect mower drive belt installation - Check drive belt for correct installation
Uncut grass when mowing
Cutting deck is clogged - Check cutting deck and clean as necessary
Blades are excessively dull - Blades need to be sharpened
Worn or damaged blades - Install new blades
Ground speed is too fast - Use a lower speed
Cutting level is too low - Use a higher cutting height
Filled grass bag - Remove grass from bag
Blade scalped grass
Lawn is bumpy or not smooth - Lawn needs to be leveled
Mower deck cutting height is set too low - Use correct cutting height
Fast ground speed - Operate at slower speed
Deck is not leveled correctly - Deck should be adjusted correctly
Blades are worn or bent - Blades need to be replaced
Tires are not correctly inflated - Inflate tires correctly
Uneven cutting
Tire pressure is too low - Need to inflate tires
Improperly leveled mower deck - Adjust mower deck level properly
Not sharp blades - Need a blade sharpening
Worn or defective blades - Install new blades
Clogged mower deck - Mower deck needs to be cleaned
Deck housing is broken - Repair or replace the deck
Loose or defective mower spindle - Install new spindle or repair it

Electrical Troubleshooting
Battery won’t charge
Corroded or loose electrical wire connections - Clean or tighten wiring connections
Battery terminal connectors are faulty - Terminal connectors need to be changed
Dead cell in battery - Install a new battery
Starter turns slowly
Low battery power - Low battery charging, charge as required
Battery runs out quickly - Battery needs service or replacement
Disconnected wiring or bad battery terminals - Connect wires properly or change terminals
Starter motor is not working
Battery is drained or defective - Charge or replace the battery
Battery wires are disconnected or incorrectly connected - Check wires and connect correctly
Low battery output - Battery is drained, charge it
Spark plug gapped improperly or faulty - Clean and gap or replace
Damaged starter motor or solenoid - Repair starter or change solenoid



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