Echo Engine Torque Specs

Echo is the one handheld 2-stroke brand on this site whose documents are all first-party: every figure below was read from a PDF hosted on echo-usa.com or from Yamabiko's own service manual, rather than a dealer re-host. The SRM-2620ES service manual carries a complete "Torque Limits" table — the most thorough published table of any handheld engine here — and it prints every value three ways, in kgf-cm, N·m and in-lbf, which makes each row self-checking. Note that Echo specifies most of these as bands, and that its M10 spark plug takes far less than the M14 plug on a Stihl or Husqvarna saw.

Where these numbers come from: The SRM-2620ES "1-3 Torque Limits" table is the primary source and also covers the Shindaiwa T262XS/C262S/T262TXS/C262TS. The CS-400, CS-590 and SRM-225 figures come from Echo operator's manuals on echo-usa.com, where they are printed as formal spec callouts rather than running text. Values are shown in the unit Echo itself printed — in-lb where Echo prints lbf-in, ft-lb where the figure is high enough for a ft-lb wrench to read it — with Echo's N·m figure recorded on every row. Echo also publishes a general fastener table for unlisted hardware (M3 0.6-1, M4 1.5-2.5, M5 2.5-4.5, M6 4.5-7.5, M8 11-15 N·m); that is a fallback for hardware with no specific spec, not a substitute for the rows below. Two documented gaps: the CS-590 operator's manual prints no muffler-bolt figure although the CS-400's does, and the CS-310/CS-352 were not checked.

Echo SRM-2620ES / SRM-2620TES (25.4cc)

Model series: SRM-2620ES, SRM-2620TES; also Shindaiwa T262XS, C262S, T262TXS, C262TS

From the official Yamabiko/Echo service manual, section "1-3 Torque Limits". The table prints kgf-cm first, then N·m, then in-lbf — three units for every row, which means each value cross-checks against itself. This is the most complete published fastener table of any handheld engine on this site.

ComponentTorqueThreadConfidenceNotes
cutter fastener (left-hand thread)21–24 ft-lbLM10high28-32 N·m (280-320 kgf-cm). LEFT-HAND thread — it loosens clockwise. The highest torque on the machine, and the one most often ruined by turning it the wrong way.
magneto rotor (flywheel)12–15 ft-lbM8high16-20 N·m (160-200 kgf-cm, 140-175 in-lbf). Far below a 4-stroke crankshaft flywheel nut — a handheld magneto rotor is an M8 fastener, not the 125 ft-lb item on a Honda GX270.
spark plug7–11 ft-lbM10high10-15 N·m (100-150 kgf-cm, 87-130 in-lbf). This is an M10 plug, which is why it takes roughly half what the M14 plug on a Stihl or Husqvarna chainsaw does. Match the figure to your plug thread, not to "2-stroke".
clutch shoe62–97 in-lbM6high7-11 N·m (70-110 kgf-cm, 60-95 in-lbf).
cylinder screw62–97 in-lbM5high7-11 N·m (70-110 kgf-cm). Cylinder and head are one casting on a 2-stroke — not a head-bolt sequence.
crankcase screw62–97 in-lbM5high7-11 N·m (70-110 kgf-cm).
muffler62–97 in-lbM5high7-11 N·m (70-110 kgf-cm).
starter pawl assembly62–97 in-lbM8high7-11 N·m (70-110 kgf-cm).
starter case35–53 in-lbM5high4-6 N·m (40-60 kgf-cm).
muffler cover, crankcase side27–40 in-lbM5high3-4.5 N·m (30-45 kgf-cm). Note this differs from the starter-side cover screw below — Echo gives the two sides different figures.
muffler cover, starter side22–31 in-lbM5high2.5-3.5 N·m (25-35 kgf-cm). The lowest figure in the table.

Echo CS-400 (40.2cc)

Model series: CS-400

From the Echo CS-400 operator's manual on echo-usa.com, where these appear as formal "fastening torque" spec callouts rather than running prose. Echo prints N·m, kgf-cm and lbf-in; the in-lb values below are Echo's own printed figures.

ComponentTorqueThreadConfidenceNotes
guide bar nut175–200 in-lb—high20-23 N·m (200-230 kgf-cm) — about 15-17 ft-lb. Echo is one of the few handheld manufacturers that publishes a guide-bar-nut figure at all; Husqvarna's workshop manuals do not.
spark plug130–150 in-lb—high15-17 N·m — about 11-12.5 ft-lb. Printed by Echo as "fastening torque".
muffler mounting bolt / nut70–95 in-lb—high8-11 N·m. Two-stage: tighten cold, then re-tighten after the saw has warmed up.

Echo CS-590 Timber Wolf (59.8cc)

Model series: CS-590, CS-600P

From the Echo CS-590 operator's manual on echo-usa.com. The bar-nut and spark-plug figures are identical to the CS-400's despite the much larger engine — Echo uses one spec across the range for both.

ComponentTorqueThreadConfidenceNotes
guide bar nut175–200 in-lb—high20-23 N·m — about 15-17 ft-lb. Same as the CS-400.
spark plug130–150 in-lb—high15-17 N·m — about 11-12.5 ft-lb. Matches the CS-400 exactly.
muffler mounting bolt / nutNot published—GAP: the CS-590 operator's manual prints no muffler-bolt torque, although the CS-400's does (8-11 N·m). The CS-400 figure is not carried over here — same brand is not the same engine, and this is a 59.8cc saw against a 40.2cc one.

Echo SRM-225 trimmer (21.2cc)

Model series: SRM-225, SRM-225i; GT-225 shares the powerhead

From the Echo SRM-225 operator's manual on echo-usa.com. This manual prints kgf-cm and in-lbf only, with no N·m column — the N·m figures in the notes below are conversions from Echo's printed values, not Echo's own.

ComponentTorqueThreadConfidenceNotes
spark plug130–150 in-lb—high150-170 kgf-cm as printed, which converts to 14.7-16.7 N·m. Identical in-lbf figures to the CS-400 and CS-590 spark plug — a useful cross-check that Echo uses one plug spec across the range. Plug: NGK BPM-8Y.
muffler mounting bolt / nut80–95 in-lb—high90-110 kgf-cm as printed, which converts to 9.0-10.7 N·m. Two-stage: tighten, run, re-tighten.

What is the spark plug torque on an Echo trimmer or chainsaw?

It depends on the plug thread, and Echo publishes both. The SRM-2620ES service manual specifies 10-15 N·m (about 7-11 ft-lb) for its M10 plug, while the CS-400, CS-590 and SRM-225 manuals all give 130-150 lbf-in (15-17 N·m, about 11-12.5 ft-lb). Either way an Echo plug takes roughly half what the M14 plug on a Stihl chainsaw does at 25 N·m. This is the clearest illustration on the site that "2-stroke spark plug torque" is not one number — match the figure to the plug thread on your machine.

What torque do Echo guide bar nuts take?

20-23 N·m — Echo prints it as 175-200 lbf-in — and the figure is the same on the 40cc CS-400 and the 59.8cc CS-590. Echo is unusual in publishing this at all: Husqvarna's workshop manuals for the 435 through 450 contain no guide-bar-nut torque anywhere. That makes Echo's number a useful sanity check on the 20-30 ft-lb bar-nut figures that circulate for other brands, which are 27-41 N·m — well above what the one manufacturer who does publish a spec considers right for the same joint.

Is the Echo trimmer cutter fastener a left-hand thread?

Yes. The SRM-2620ES service table lists it as LM10 with a left-hand thread, and it is the highest-torque fastener on the machine at 28-32 N·m (about 21-24 ft-lb). That combination — highest torque plus reverse thread — is why it is the fastener most often destroyed on these trimmers. It loosens clockwise. Confirm the direction before applying real force.

Why does Echo give two different muffler cover torques?

Because the two sides are different fasteners in different material. The SRM-2620ES table specifies 2.5-3.5 N·m for the starter-side cover screw and 3-4.5 N·m for the crankcase-side one — a real difference, not a rounding artifact, and both are low enough that only an in-lb wrench or a calibrated screwdriver can set them. The muffler itself is separate again at 7-11 N·m.

My Echo manual gives no torque for the bolt I am working on. What should I use?

Echo publishes a general fastener table for exactly that case: M3 0.6-1 N·m, M4 1.5-2.5, M5 2.5-4.5, M6 4.5-7.5 and M8 11-15 N·m. Use it only where there is no specific figure — a fastener that has its own row is not covered by the general table, and several on the SRM-2620ES (the cutter fastener at 28-32 N·m on an LM10, the magneto rotor at 16-20 N·m on an M8) sit well outside what the generic figure for their thread size would suggest.

Why is the muffler bolt torque missing for the CS-590?

Because Echo does not print it in that manual. The CS-400 operator's manual gives 8-11 N·m for its muffler bolts and the CS-590's does not give a figure at all. Rather than carry the CS-400 number across, this page records the gap: a 59.8cc saw and a 40.2cc saw are different engines, and borrowing a spec between them because the badge matches is the mistake these tables exist to prevent. Echo's general M5 figure (2.5-4.5 N·m) is not a substitute either, since the CS-400's own muffler spec sits above it.

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