Chainsaw

Stihl MS 251

2-Stroke

The Stihl MS 251 is a 45.6cc 2-stroke chainsaw and the direct successor to the MS 250, updated with a more fuel-efficient engine, improved anti-vibration, and current emission standards. It accepts 16" to 18" guide bars and occupies the same homeowner/prosumer position. Unlike the MS 250, the MS 251 does not share a carburetor with the MS 210/230 family — it runs its own Zama variant. Routine maintenance items are the air filter, spark plug, fuel lines, and primer bulb. The MS 251 is the recommended current-production choice over the MS 250 generation.

See a wrong fitment? Report a correction.

Verify before ordering: Fitment can vary by serial number, production date, region, and sub-model. Match the OEM number and physical dimensions before ordering.

Equipment: Chainsaw · 2-Stroke
Covered Parts: Spark Plug, Air Filter, Fuel Filter, Carburetor, Recoil Starter, Ignition Coil, Primer Bulb, Fuel Line Kit, Chain, Guide Bar
OEM References: 0000 400 7000, 1143 120 1300, 0000 350 3518, 1143 120 0611, 1143 080 2103, 1143 400 1310, 1143 350 6200, 1143 358 7700
Model Family: MS 210, MS 230, MS 250, MS 251
Last Reviewed: 2026-05-20
Data Confidence: Aftermarket-confirmed
Sources Consulted: OEM part references, Aftermarket catalog cross-references, Retailer fitment listings

ℹ See also: MS 210, MS 230, MS 250 — parts are often interchangeable within this family.

Quick Fitment

Part Type	OEM / Spec	Common Option	Confidence
Spark Plug	0000 400 7000	NGK BPMR7A	Medium · 2026-05-20
Air Filter	1143 120 1300	OEM 1143 120 1300	Low · 2026-05-20
Fuel Filter	0000 350 3518	OEM 0000 350 3518	Low · 2026-05-20
Carburetor	1143 120 0611	Zama C1Q-S295D	Medium · 2026-05-20
Primer Bulb	1143 350 6200	Zama BG-00-4	Medium · 2026-05-20
Recoil Starter	1143 080 2103	OEM 1143 080 2103	Low · 2026-05-20
Ignition Coil	1143 400 1310	OEM 1143 400 1310	Low · 2026-05-20
Fuel Line Kit	1143 358 7700	OEM 1143 358 7700	Low · 2026-05-20

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 MS 251, 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.
Matching bar length but missing pitch, gauge, or drive-link count.

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

Cuts slowly

Chain pitch/gauge, bar wear, drive links

Replacement Options

Best OEM equivalent

Start with OEM references 0000 400 7000, 1143 120 1300, 0000 350 3518, 1143 120 0611 and match the removed part before choosing a listing.

Common aftermarket option

Cross-check aftermarket listings such as NGK BPMR7A (spark plug), Zama C1Q-S295D (carburetor), Zama BG-00-4 (primer bulb) against the OEM number and dimensions.

Best for annual tune-up

Bundle spark plug, air filter, fuel filter when servicing the Stihl MS 251 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 chain/bar combo

Match chain specs together, especially pitch, gauge, drive links, and bar mount details.

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 MS 210 or MS 230? Parts may interchange with MS 210, MS 230, MS 250, but verify the serial range, OEM number, and physical part details before ordering.

Should I buy OEM or aftermarket parts for the Stihl MS 251? 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 MS 251? 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.

What chain details matter besides bar length? Match pitch, gauge, and drive-link count against the bar stamp, old chain, and drive sprocket. Bar length alone is not enough.

Spark Plug

OEM0000 400 7000Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Dimensions: 0.5mm gap

Brand	Part #
NGK	BPMR7A	Best for annual tune-upAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.
Champion	RCJ6Y	Best for annual tune-upAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Air Filter

OEM1143 120 1300Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Fits MS 231, MS 251

Brand	Part #
No aftermarket listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Fuel Filter

OEM0000 350 3518Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: In-tank pickup body fuel filter; updated version for MS 231, MS 251

Brand	Part #
No aftermarket listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Carburetor

OEM1143 120 0611Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Zama C1Q-S295D IntelliCarb compensating carburetor; fits MS 231, MS 251

Brand	Part #
Zama	C1Q-S295D	Best if replacing fuel systemAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Recoil Starter

OEM1143 080 2103Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Fits MS 231, MS 251

Brand	Part #
No aftermarket listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Ignition Coil

OEM1143 400 1310Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Fits MS 231, MS 251

Brand	Part #
No aftermarket listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Primer Bulb

OEM1143 350 6200Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Fits MS 231, MS 251

Brand	Part #
Zama	BG-00-4	Best if replacing fuel systemAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Fuel Line Kit

OEM1143 358 7700Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Fuel hose for MS 231, MS 251

Brand	Part #
No aftermarket listing is published for this part yet. Use the OEM reference and verify with a dealer or service manual before ordering.

Chain

OEMSpec-based fitmentConfidence: Low · Source: Inferred

Reviewed: 2026-05-20
Dimensions: 18", .325" pitch, .050" gauge, 68 drive links
Variant notes: Stock bar length; verify drive link count matches your bar

Brand	Part #
Oregon	22LPX068G	Best chain/bar comboAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Guide Bar