Husqvarna 224T Service Manual

The Husqvarna 224T is a lightweight, professional-grade trimmer designed for demanding users. This manual provides detailed service, maintenance, and repair information for the 224T trimmer, including its 2-stroke engine, cutting head, shaft, and controls. Below are key sections covering safety, specifications, maintenance procedures, troubleshooting, and parts information.

1. Features at a Glance 2. Safety Information 3. Specifications 4. Maintenance Schedule 5. Engine Service 6. Fuel System 7. Ignition System 8. Cutting Attachment 9. Drive Shaft & Gearhead 10. Troubleshooting 11. Parts List & Diagrams

Features at a Glance

Key components: 2-stroke engine, Straight shaft, Tap-and-go cutting head, Anti-vibration system, Air purge bulb, Adjustable handle.

Feature	Description
Engine Type	2-stroke, air-cooled
Displacement	24.5 cc
Power Output	0.8 kW (1.1 hp)
Fuel Tank Volume	0.47 liters
Cutting Attachment	Tap-and-go trimmer head (2.4 mm line)
Shaft Type	Straight, solid
Drive System	Flexible drive shaft
Weight (without cutting attachment)	4.7 kg
Sound Pressure Level	Approx. 94 dB(A)
Vibration Level (front/rear handle)	Approx. 3.5/2.5 m/s²

Safety Information

Always follow safety precautions to prevent serious injury or death.

Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, gloves, long pants, and sturdy boots.
Fuel Safety: Refuel in a well-ventilated area with the engine stopped and cool. Use fuel mix (50:1 gasoline to 2-stroke oil).
Operation Area: Keep bystanders, especially children and pets, at least 15 meters away.
Hot Surfaces: Do not touch the muffler or cylinder during or immediately after operation.
Transport & Storage: Secure the unit during transport. Store fuel in an approved container away from sparks or flame.

WARNING! The cutting tool can cause severe injury. Never operate the trimmer without the proper guard installed and in good condition.

Specifications

Model: Husqvarna 224T
Engine Model: Husqvarna 224L
Displacement: 24.5 cm³
Cylinder Bore: 34.0 mm
Piston Stroke: 27.0 mm
Idle Speed: 2800 rpm
Maximum Power Speed: 9000 rpm
Ignition System: Electronic, SEM
Spark Plug: Champion RCJ7Y or equivalent, gap 0.5 mm (0.020")
Carburetor: Zama C1U, adjustable (H, L, T)
Fuel Recommendation: Unleaded gasoline (min 90 octane) mixed with Husqvarna 2-stroke oil (50:1)
Recommended Cutting Equipment: Husqvarna Tap-and-go trimmer head, 2.4 mm line

Maintenance Schedule

Regular maintenance is essential for safe operation and long service life.

Interval	Task
Before each use	Check for loose nuts/bolts, inspect cutting attachment and guard, check throttle trigger function.
Daily	Clean air filter, check spark plug condition, clean exterior of unit.
Every 25 hours	Clean spark arrestor screen in muffler, check fuel filter, inspect drive shaft.
Every 50 hours	Replace spark plug, clean carburetor (if necessary), check anti-vibration elements.
Every 100 hours	Replace fuel filter, inspect and clean cylinder fins, check clutch and gearhead.
Annually or as needed	Replace air filter, check all cables and linkages, professional inspection recommended.

CAUTION! Always disconnect the spark plug wire before performing any maintenance.

Engine Service

Procedures for cylinder, piston, crankshaft, and bearings.

Cylinder & Piston Inspection: Remove muffler and spark plug. Look into exhaust port to inspect piston skirt and rings for scoring.
Compression Test: Use compression gauge. Minimum acceptable compression is 110 psi (7.6 bar). Low compression indicates worn rings, piston, or cylinder.
Crankcase Seals: Check for air leaks. Leaking seals cause poor performance and overheating.
Muffler: Remove and clean spark arrestor screen regularly to prevent power loss and overheating.
Cooling Fins: Keep cylinder cooling fins clean of grass and debris to prevent overheating.

Note: Major engine disassembly requires special tools and expertise.

Fuel System

Carburetor adjustment and fuel line service.

Fuel Lines: Inspect for cracks or brittleness. Replace if damaged.
Fuel Filter: Located inside the fuel tank. Replace by pulling out with a wire hook.
Carburetor Adjustment (Zama C1U):
- L (Low Speed): Adjust idle mixture. Turn clockwise until engine runs poorly, then counterclockwise 1/4 turn.
- H (High Speed): Adjust maximum power. Do not exceed factory setting. Typically set for 12,000-13,000 rpm under load.
- T (Idle Speed): Adjust idle speed to 2800 rpm.
Air Filter: Clean with warm soapy water, dry, and re-oil with Husqvarna filter oil.

WARNING! Use only fresh, properly mixed fuel. Stale fuel is the most common cause of starting and running problems.

Ignition System

Spark plug, ignition module, and stop switch.

Spark Plug: Use Champion RCJ7Y or equivalent. Set gap to 0.5 mm (0.020"). Replace if electrodes are worn or insulator is cracked.
Ignition Module (SEM): Check for spark. Remove spark plug, connect to wire, ground plug against cylinder, and pull starter. Look for strong blue spark.
Air Gap: Gap between ignition module flywheel magnets and coil legs is non-adjustable. If no spark, replace module.
Stop Switch: Test for continuity. The switch should be open (no continuity) in RUN position and closed (continuity) in STOP position.

Cutting Attachment

Trimmer head service and line replacement.

Tap-and-Go Head: To advance line, tap the head on the ground while the engine is at high idle speed.
Replacing Line:
- Remove the spool cover by pressing in the tabs on the sides.
- Remove old line and clean spool.
- Wind approx. 6 meters of 2.4 mm line onto the spool in the direction of the arrow.
- Thread the ends through the eyelets and reassemble.
Cutting Guard: Inspect for cracks or damage. Replace if compromised.
Shaft Connection: Ensure the drive square on the shaft is not worn and engages properly with the head.

Drive Shaft & Gearhead

Flexible shaft and gearhead lubrication.

Drive Shaft Lubrication: Disconnect shaft from engine. Apply Husqvarna drive shaft grease to the flexible cable before reinserting.
Gearhead: The gearhead is filled with grease at the factory. Check for leaks and unusual noise. If service is required, disassemble, clean, and repack with Husqvarna gear grease.
Clutch: The centrifugal clutch engages at approximately 2800 rpm. Inspect shoes for wear and springs for damage.

Tip: A noisy gearhead often indicates lack of lubrication or worn bearings.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, stale fuel, flooded engine, clogged fuel filter	Check spark plug and ignition. Use fresh fuel mix. Check fuel lines and filter. Choke properly.
Engine starts but dies	Clogged carburetor, air leak, faulty fuel pump diaphragm	Clean carburetor. Check crankcase seals and intake manifold. Replace diaphragm.
Loss of power	Dirty air filter, clogged muffler, worn piston/rings	Clean air filter and spark arrestor. Check compression.
Excessive vibration	Unbalanced cutting head, bent shaft, loose components	Replace trimmer line evenly. Check shaft for straightness. Tighten all bolts.
Cutting head does not turn	Broken drive shaft, worn clutch, stripped gearhead	Inspect flexible shaft. Check clutch shoes. Inspect gearhead gears.
Line does not advance	Worn bump knob, tangled line, eyelets clogged	Replace tap-and-go mechanism. Rewind line spool correctly. Clean eyelets.

Reset: For electronic ignition issues, ensure all wiring connections are secure.

Parts List & Diagrams

Refer to the official Husqvarna 224T Parts Manual (Part No. 590 79 01-01) for exploded views and part numbers for all components including engine assembly, fuel system, ignition, shaft, cutting attachment, and handles.

Common Replacement Parts:

Air Filter: Part No. 503 92 96-01
Spark Plug: Champion RCJ7Y
Fuel Filter: Part No. 544 11 84-01
Tap-and-Go Head: Part No. 579 47 47-01
Trimmer Line (2.4 mm): Part No. 531 00 66-03
Carburetor Repair Kit: Part No. 530 03 61-01

Service Support: For technical assistance or to order parts, contact an authorized Husqvarna service dealer or visit www.husqvarna.com.