Trimmer
Stihl FS 38
2-Stroke
The Stihl FS 38 is a 27.2cc 2-stroke curved-shaft grass trimmer and the entry point to Stihl's FS consumer trimmer range. Designed for residential lawn edging and light grass trimming, it is not suited for heavy brush or commercial use. The FS 38 uses a bump-feed head accepting .080" round line and runs a Zama carburetor. Common failure modes are primer bulb cracking and fuel line deterioration from ethanol exposure. The FS 38 shares its engine architecture and air filter design with the FS 40 and FS 45, giving it good parts availability.
Stihl FS 38 quick specs
- Equipment
- Trimmer · 2-Stroke
- Covered Parts
- Spark Plug, Air Filter, Fuel Filter, Carburetor, Primer Bulb, Fuel Line Kit, Trimmer Head, Trimmer Line
- OEM References
- 0000 400 7000, 4140 124 2800, 0000 350 3502, 4140 120 0610, 4226 121 2700, 4140 358 7702, 4006 710 2126
- Model Family
- FS 38, FS 40, FS 45, FS 55
- Last Reviewed
- 2026-05-21
- Data Confidence
- Aftermarket-confirmed
- Sources Consulted
- Stihl FS 38 parts references
- Aftermarket catalog cross-references
- Retailer fitment listings
Quick Fitment
- Spark PlugOEM / Spec: 0000 400 7000NGK BPMR7AMedium confidence · Aftermarket catalog · reviewed 2026-05-21View on Amazon →Affiliate link
- Air FilterOEM / Spec: 4140 124 2800OEM 4140 124 2800Medium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- Fuel FilterOEM / Spec: 0000 350 3502OEM 0000 350 3502Medium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- CarburetorOEM / Spec: 4140 120 0610Zama C1Q-S58BMedium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- Primer BulbOEM / Spec: 4226 121 2700Zama 0057004Medium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- Trimmer HeadOEM / Spec: 4006 710 2126Oregon 55-265Medium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- Fuel Line KitOEM / Spec: 4140 358 7702Hipa 4140 358 7702Medium confidence · Aftermarket catalog · reviewed 2026-05-21Search Amazon →Affiliate link
- Trimmer LineOEM / Spec: .080" diameter, roundOregon 22-895Low confidence · Inferred · reviewed 2026-05-21Search Amazon →Affiliate link
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Tune-Up Kit
Common service bundle: spark plug, air filter, fuel filter, carburetor, primer bulb, fuel line kit.
Maintenance Interval
Inspect filters and fuel lines each season, replace spark plugs during annual service, and service carb/fuel-system parts when starting or idle symptoms appear.
Before You Buy
- Confirm the full model is Stihl FS 38, not just the family name.
- Check serial number, production date, and regional variant before ordering.
- Match the old OEM number stamped on the removed part when available.
- Compare dimensions, plug gap, thread, fuel line diameter, or chain pitch/gauge where applicable.
Common Mistakes
- Ordering from a family listing without checking the exact sub-model.
- Buying a kit that includes the headline part but wrong gaskets, lines, or bulb size.
- Choosing the wrong carburetor revision when multiple versions were used.
- Assuming all fuel line kits use the same diameter and routing.
- Installing the correct plug number with the wrong gap.
Symptoms Map
Won't start
Spark plug, fuel filter, primer bulb, carburetor
Starts then dies
Fuel filter, fuel line kit, carburetor
Bogs under throttle
Air filter, carburetor, spark plug gap
Primer will not fill
Primer bulb, fuel line routing, in-tank filter
Replacement Options
Best OEM equivalent
Start with OEM references 0000 400 7000, 4140 124 2800, 0000 350 3502, 4140 120 0610 and match the removed part before choosing a listing.
Named part options
Cross-check named parts such as NGK BPMR7A (spark plug), Zama C1Q-S58B (carburetor), Zama 0057004 (primer bulb) against the OEM number, identity label, and dimensions.
Best for annual tune-up
Bundle spark plug, air filter, fuel filter when servicing the Stihl FS 38 at the start of the season.
Best if replacing fuel system
Compare the fuel filter, carburetor, primer bulb, fuel line kit together so line routing, bulb size, filter style, and carburetor connections match.
Best budget kit
Use kit listings only when every included part matches this model page; cheap kits often mix correct headline parts with wrong bulbs, lines, or gaskets.
FAQ
Does this fit FS 40 or FS 45? FS 40, FS 45, FS 55 are listed in the same model family. That relationship does not establish interchangeable parts; verify each OEM number, serial range, and physical detail separately.
Should I buy OEM or aftermarket parts for the Stihl FS 38? Use OEM when the part controls fuel metering, ignition, or safety. Aftermarket kits can be useful for routine filters, bulbs, plugs, and tune-up bundles when the OEM number and dimensions match.
How do I avoid ordering the wrong carburetor for the FS 38? Match the carburetor number stamped on the removed unit, then compare linkage, choke setup, primer routing, gasket stack, and fuel-inlet direction.
What should I check before replacing fuel-system parts? Photograph the old fuel-line routing, match line diameter and filter style, and compare primer bulb size before buying a kit.
Related Repair Guides
As an Amazon Associate, WhichPartFits earns from qualifying purchases. Match the OEM number, dimensions, and model variant before buying.
Spark Plug
- Reviewed
- 2026-05-21
- Dimensions
- 0.7mm gap
Air Filter
- Reviewed
- 2026-05-21
- Variant notes
- Also fits FS 45, FS 46, FS 55, HS 45, KM 55
- No named part listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.
Fuel Filter
- Reviewed
- 2026-05-21
- Variant notes
- 3/16" ID in-tank filter; also fits FS 45, FS 46, FS 55
- No named part listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.
Carburetor
- Reviewed
- 2026-05-21
- Variant notes
- Zama C1Q-S58B; also fits FS 45, FS 46
- ZamaC1Q-S58B
Primer Bulb
- Reviewed
- 2026-05-21
- Variant notes
- Match bulb diameter, port count, and port orientation before ordering.
Fuel Line Kit
- Reviewed
- 2026-05-21
- Variant notes
- Includes fuel pickup line and return line; also fits FS 45, FS 55
- Hipa4140 358 7702
Trimmer Head
- Reviewed
- 2026-05-21
- Variant notes
- AutoCut C 6-2; bump-feed; .080" line
- Oregon55-265
Trimmer Line
- Reviewed
- 2026-05-21
- Dimensions
- .080" diameter, round
- Oregon22-895
- Arnold490-080-0100