Trimmer

Echo SRM-266

2-Stroke

The Echo SRM-266 is a 25.4cc 2-stroke straight-shaft trimmer in the upper tier of Echo's commercial SRM lineup, producing significantly more torque than the SRM-225/230 class for heavy brush, tough grass, and demanding vegetation management. It runs a Zama carburetor and is capable of driving brush blade attachments. Under commercial production use, the SRM-266 warrants monthly fuel system inspection and air filter service. The gearhead should be inspected and greased seasonally. A step toward a dedicated brush cutter for operators who regularly encounter thick growth.

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: Trimmer · 2-Stroke
Covered Parts: Spark Plug, Air Filter, Fuel Filter, Carburetor, Recoil Starter, Primer Bulb, Fuel Line Kit, Trimmer Head, Trimmer Line
OEM References: 90023Y, A226000640, A369000100, 12520005563, A180001100, 12318139130, V471001471, 99944200903
Model Family: SRM-266, SRM-266S
Last Reviewed: 2026-05-20
Data Confidence: Aftermarket-confirmed
Sources Consulted: OEM part references, Aftermarket catalog cross-references, Retailer fitment listings

ℹ See also: SRM-266S — parts are often interchangeable within this family.

Quick Fitment

Part Type	OEM / Spec	Common Option	Confidence
Spark Plug	90023Y	Champion CJ8Y	Medium · 2026-05-20
Air Filter	A226000640	Stens 605-543	Medium · 2026-05-20
Fuel Filter	A369000100	Stens 610-009	Medium · 2026-05-20
Carburetor	12520005563	Zama C1U-K82	Medium · 2026-05-20
Primer Bulb	12318139130	Zama BG-00-4	Medium · 2026-05-20
Trimmer Head	99944200903	Oregon 55-256	Medium · 2026-05-20
Recoil Starter	A180001100	OEM A180001100	Low · 2026-05-20
Fuel Line Kit	V471001471	Stens 115-530	Medium · 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 Echo SRM-266, 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 90023Y, A226000640, A369000100, 12520005563 and match the removed part before choosing a listing.

Common aftermarket option

Cross-check aftermarket listings such as Champion CJ8Y (spark plug), Stens 605-543 (air filter), Stens 610-009 (fuel filter) against the OEM number and dimensions.

Best for annual tune-up

Bundle spark plug, air filter, fuel filter when servicing the Echo SRM-266 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 SRM-266S? Parts may interchange with SRM-266S, but verify the serial range, OEM number, and physical part details before ordering.

Should I buy OEM or aftermarket parts for the Echo SRM-266? 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 SRM-266? 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.

Spark Plug

OEM90023YConfidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Dimensions: 0.6mm gap

Brand	Part #
Champion	CJ8Y	Best for annual tune-upAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.
NGK	BPM8Y	Best for annual tune-upAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Air Filter

OEMA226000640Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Also fits SRM-266S, SRM-266T

Brand	Part #
Stens	605-543	Best for annual tune-upAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Fuel Filter

OEMA369000100Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: In-tank pickup filter; fits most Echo chainsaws and trimmers

Brand	Part #
Stens	610-009	Best if replacing fuel systemAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Carburetor

OEM12520005563Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Zama C1U-K82; 25.4cc engine

Brand	Part #
Zama	C1U-K82	Best if replacing fuel systemAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Recoil Starter

OEMA180001100Confidence: Low · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Also fits SRM-266S

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

OEM12318139130Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20

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

OEMV471001471Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Includes fuel pickup line and return line

Brand	Part #
Stens	115-530	Best if replacing fuel systemAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Trimmer Head

OEM99944200903Confidence: Medium · Source: Aftermarket catalog

Reviewed: 2026-05-20
Variant notes: Speed-Feed 400; bump-feed

Brand	Part #
Oregon	55-256	Best overallAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.

Trimmer Line

OEMSpec-based fitmentConfidence: Low · Source: Inferred

Reviewed: 2026-05-20
Dimensions: .095" diameter, round

Brand	Part #
Oregon	22-895	Best overallAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.
Arnold	490-095-0100	Best overallAmazonAffiliate link Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.