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Description
4128 121 8900 STIHL Pin – Genuine OEM Part
The STIHL Pin (4128 121 8900) is a genuine OEM replacement component designed for use in the carburetor assemblies of many STIHL trimmers, brushcutters, KombiSystem units, hedge trimmers, and multi-purpose equipment. This pin plays an important role in securing and supporting internal carburetor components to ensure proper fuel delivery and reliable engine performance.
Manufactured to STIHL’s exact specifications, this OEM pin ensures correct fitment, dependable operation, and long-lasting durability when replacing worn or missing carburetor hardware.
Product Details
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OEM Part Number: 4128 121 8900
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Brand: STIHL (OEM)
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Part Type: Pin
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Application: Carburetor Assembly (C1Q Series & Related Models)
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Condition: New Genuine OEM Part
Function
This pin is designed to:
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Secure internal carburetor components in place
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Support proper fuel metering and carburetor operation
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Replace worn, bent, or missing carburetor pins
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Restore correct carburetor performance
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Maintain reliable engine starting and running
⚠️ A missing or damaged carburetor pin may cause improper fuel delivery or poor engine performance.
Verify Fitment in 30 Seconds
Before ordering, confirm the following:
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OEM part number 4128 121 8900
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Part location: carburetor assembly
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Compatible STIHL model listed below
⚠️ Always verify fitment by OEM part number for best accuracy.
Compatibility
Fits a wide range of STIHL equipment, including:
Trimmers / Brushcutters
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FS 38, FS 38 2-MIX
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FS 45, FS 45 D, FS 45 C-E
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FS 46, FS 46-D, FS 46 C-E, FS 46 C-E D
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FS 55, FS 55 R, FS 55-D
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FS 55 RC-E, FS 55 RC-E D, FS 55 C-E D
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FS 75
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FS 80, FS 80 R
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FS 85, FS 85 R, FS 85 RX
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FS 120, FS 120 R
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FS 200 R
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FS 250, FS 250 R
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FS 350
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FS 450-K
KombiSystem Units
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KM 55 R, KM 55 R-D
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KM 55 RC-E, KM 55 RC-E D
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KM 85 R
Hedge Trimmers / Long Reach Units
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HL 45, HL 45-D
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HL 75, HL 75 K
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HT 75
Cultivators / Yard Boss
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MM 55, MM 55 C-E
Edgers / Specialty Units
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FC 55, FC 55-D
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FC 75
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FC 85
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KW 85
Augers
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BT 45
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BT 120 C
⚠️ This list includes common applications — always confirm using your parts diagram or owner’s manual.
Installation / Usage
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Turn off engine and allow it to cool completely
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Remove air filter cover and carburetor access components
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Disassemble carburetor carefully in a clean workspace
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Replace the worn or missing pin with the new STIHL OEM part
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Reassemble carburetor and test engine operation
⚠️ Carburetor service should be performed by a qualified technician if unsure.
Maintenance Tips
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Keep fuel system clean and use fresh fuel mix
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Inspect carburetor components regularly for wear
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Replace damaged pins immediately to prevent running issues
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Clean air filter often to reduce carburetor contamination
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Use only genuine STIHL replacement parts for best fit and reliability
