Shop replacement repair parts for Stihl String Trimmer model FS 56

NGK spark plug (CMR6A)

Champion Spark Plug (CJ8)

Starter spring
Keep your Stihl FS 56 string trimmer operating reliably with genuine OEM replacement parts from Repair Clinic. The Stihl FS 56 is a lightweight consumer-grade gas string trimmer with a 27.2 cc two-stroke engine and a straight shaft design. The FS 56 RC variant adds the Easy2Start decompression system while sharing most engine and fuel system components with the standard FS 56. The carburetor, air filter, fuel filter, fuel line, and spark plug are the most frequently serviced components across the FS 56 service life. Repair Clinic stocks genuine Stihl OEM parts for the FS 56 including the Stihl trimmer carburetor parts, Stihl trimmer air filter parts, Stihl trimmer spark plug parts, Stihl trimmer ignition coil parts, and Stihl trimmer string head parts. Browse the Stihl string trimmer parts catalog filtered by FS 56 for the complete parts inventory.
The Stihl FS 56 uses a 27.2 cc two-stroke engine with a diaphragm carburetor and a separate fuel tank mounted on the shaft. The FS 56 RC adds the Stihl Easy2Start decompression valve to the same engine platform, reducing pull-starter resistance while sharing all carburetor, fuel filter, and ignition components with the standard FS 56. The centrifugal clutch engages the drive shaft at a specific RPM threshold and is the component to inspect when the cutting head does not spin despite a running engine.
The FS 56 uses a diaphragm carburetor specific to two-stroke handheld equipment. Ethanol varnish deposits in the diaphragm chamber and needle valve seat are the leading cause of hard starting and rough running after storage. Cleaning restores function in most cases. When the diaphragm has hardened and cracked or the needle valve seat is worn, carburetor replacement is required.
The fuel filter on the FS 56 sits inside the fuel tank on the end of the fuel pickup tube. A clogged fuel filter restricts fuel delivery to the carburetor, causing lean running symptoms that are often misdiagnosed as carburetor problems. Replace the fuel filter annually before diagnosing the carburetor.
Replace the air filter at the start of each trimming season. On a two-stroke trimmer operating at high RPM in dusty conditions, the air filter clogs faster than on four-stroke mower engines. A clogged air filter causes the engine to run rich and lose power at full throttle.
Annual spark plug replacement maintains reliable starting and clean combustion in the two-stroke engine. Always use the two-stroke fuel mixture ratio specified in the Stihl FS 56 owner’s manual. An incorrect mixture ratio causes premature plug fouling.
The Stihl FS 56 is a lightweight consumer-grade gas string trimmer with a straight shaft and a 27.2 cc two-stroke engine. The FS 56 RC is the same trimmer with the addition of the Stihl Easy2Start decompression system that reduces pull-starter force required for starting. Most internal engine and fuel system components are shared between the FS 56 and FS 56 RC.
An FS 56 that starts and idles but dies when the throttle is opened is most commonly showing a lean fuel mixture from a clogged high-speed needle jet in the carburetor, a clogged fuel filter inside the fuel tank, or a cracked fuel line creating an air leak. Inspect the fuel filter and fuel lines before disassembling the carburetor.
A cutting head that does not spin when the engine is running is most commonly caused by a failed centrifugal clutch that is not engaging the drive shaft at the correct RPM threshold. Inspect the clutch shoes for wear and the clutch drum for scoring before replacing the complete clutch assembly.
The FS 56 uses a bump-feed cutting head. Remove the spool by pressing the retainer tabs. Wind new line of the correct diameter in the direction indicated by the arrow on the spool. Reinstall the spool and thread the line ends through the eyelets on the cutting head housing.

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