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Description
4229 121 4700 STIHL Metering Diaphragm – Genuine OEM Carburetor Part
The STIHL Metering Diaphragm (4229 121 4700) is a genuine OEM carburetor component designed to restore accurate fuel metering and consistent engine performance across a wide range of STIHL handheld equipment. This diaphragm plays a critical role inside the carburetor by regulating fuel flow from the metering chamber into the engine.
Over time, metering diaphragms can become stiff, cracked, or worn due to fuel exposure, heat, and age. A damaged diaphragm may cause hard starting, surging, poor idle, hesitation, or power loss. Replacing it with the correct OEM part helps restore proper carburetor function without needing to replace the entire carburetor assembly.
Manufactured to STIHL factory specifications, this genuine metering diaphragm ensures correct fitment, fuel response, and long-term durability under professional operating conditions.
Product Details
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OEM Part Number: 4229 121 4700
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Brand: STIHL (Genuine OEM)
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Part Type: Metering Diaphragm
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Application: Carburetor fuel metering system
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Condition: New Genuine OEM Part
Function
This STIHL metering diaphragm is designed to:
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Regulate fuel delivery inside the carburetor
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Maintain correct fuel–air mixture under varying engine loads
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Improve throttle response and idle stability
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Replace worn or stiff diaphragms caused by aging or contamination
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Restore reliable starting and consistent power output
⚠️ A failing metering diaphragm can cause surging, stalling, poor acceleration, or loss of engine performance.
Verify Fitment (Recommended)
Before ordering, confirm:
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OEM part number 4229 121 4700
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Your carburetor model matches those listed below
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Application matches your STIHL illustrated parts diagram
⚠️ Diaphragms are carburetor-specific — always verify by OEM part number and carburetor type.
Compatibility
This OEM metering diaphragm fits many STIHL carburetors used across blowers, trimmers, hedge trimmers, Kombi systems, and chainsaws, including:
Blowers / Sprayers / Vac Units
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BG 50 (Carburetor)
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BG 55 / BG 55 C KAT (C1Q-S68)
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BG 65 / BG 65-D (C1Q-S68)
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BG 85 / BG 85-D / BG 85 C KAT (C1Q-S68)
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SH 55 / SH 85 / SH 85-D (C1Q-S68)
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BR 45 C (C1Q-S73)
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BR 500 / BR 600 / BR 700 / BR 700 X (4282 series)
Trimmers / Brushcutters / Kombi Units
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FS 38 (C1Q-S291)
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FS 45 / FS 46 / FS 55 series (C1Q-S71)
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FS 75 / FS 80 / FS 85 series (C1Q-S157 / C1Q-S69)
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FS 120 / FS 200 R / FS 250 / FS 250 R (4134 series)
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KM 55 / KM 85 R Kombi units
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FC 55 / FC 75 / FC 85 edgers
Hedge Trimmers / Long-Reach Units
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HL 45 / HL 45-D (C1Q-S71)
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HL 75 / HL 75 K
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HS 45 (C1Q-S169 / S170 / S70)
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HS 81 / HS 82 / HS 86 / HS 87 series (C1Q-S225 / C1Q-S292)
Chainsaws
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MS 171 (C1Q-S123)
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MS 181 / MS 181 C-BE
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MS 211 / MS 211 C-BE
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MS 241 C-M (C1Q-S275 / S276 / S277)
(Exact fitment depends on carburetor type and production version — always verify using OEM parts diagram.)
Installation Notes
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Remove carburetor from the unit
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Disassemble carefully on a clean surface
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Replace metering diaphragm in correct orientation
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Reassemble carburetor and reinstall
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Adjust carburetor according to STIHL specifications
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Test engine idle and throttle response
⚠️ Carburetor service should be performed by a qualified technician.
Maintenance Tips
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Use clean, fresh fuel to prevent diaphragm damage
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Replace fuel filters and fuel lines during carburetor service
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Clean air filter regularly
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Drain fuel for long-term storage
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Always use genuine STIHL OEM carburetor components for proper calibration

