Honda GCV Series Engine Torque Specs

Cylinder head bolt torque at a glance

HighMediumLow= how many independent sources agree

Honda GCV engines power the vast majority of residential push and self-propelled mowers -- including most Honda HRX and HRN mowers -- along with pressure washers and small equipment. These fastener torque specs are pulled directly from Honda's own engine-assembly information… Read the rest ›

sheets and shop manuals, not paraphrased from a parts blog, so the cylinder/head-cover, connecting-rod, and flywheel-nut numbers below match what a Honda service tech would use. Honda redesigned this line partway through -- GCV170/GCV200 are a newer platform than GCV160/GCV190 -- and the two families genuinely use different torque tables, so they are kept separate below rather than merged.

Where these numbers come from. 43 published figures, 6 confirmed gaps, every source named. How we checked ›

GCV160/GCV190 (and the related GSV190) values come from Honda's official "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet (honda-engines-eu.com, (c) Honda Motor Co. 2009), which states one shared torque table across all four named models rather than splitting per displacement -- so those rows carry high confidence for GCV160 and GCV190 alike. Valve-clearance numbers for that family come from the separate GCV190 shop manual's maintenance-standards table; they are flagged medium confidence when carried over to GCV160 specifically, since that document does not restate them under a "GCV160" heading. GCV170/GCV200 values come from Honda's official shop manual (shop-manual-gcv145-170-200-62z9l20-en.pdf), which prints a full per-fastener torque table (N-m / kgf-m / lbf-ft) naming both engines together -- high confidence throughout. Neither generation has an oil drain-plug bolt (both drain by tilting the engine with the filler cap removed) -- that is a confirmed design fact, not a gap. Both generations DO have a published spark-plug torque of 20 N-m: shop manual 61ZM000 prints it for GCV135/160/190/GSV190 (14 ft-lb) and 62Z9L20 prints it for GCV145/170/200 (which Honda rounds to 15 lbf-ft). An earlier revision of this file recorded the older generation as having no published figure, because the GCV160 owner's manual gives the seat-then-half-turn method instead of a number; the shop manual's torque table settles it. Where the shop manual and the engine-assembly information sheet disagree on the flywheel nut, both figures are recorded on the row and the shop manual is the one published. The optional GCV530/GXV530 V-twin and GC160/GC190 horizontal-shaft siblings were also researched: GCV530/GXV530 has real sourced numbers (see below); GC160/GC190 were originally left out because the shop-manual PDF first located was a scanned "electronic shop manual" export whose in-procedure torque call-out boxes did not survive conversion (they render as empty boxes labeled only "TORQUE"). That limitation applies only to the procedural call-outs: a readable copy of the same manual (61ZL800, June 2007) was located during issue #432 and its SPECIFIC TORQUE VALUES table in the service-information section is a plain table that extracts cleanly, giving cylinder head cover bolt M6x1.0 = 12 N-m, spark plug M14x1.25 = 20 N-m, flywheel nut M14x1.5 = 52 N-m, oil drain plug M12x1.5 = 24 N-m, connecting rod bolt M7x1.0 = 12 N-m. Those figures now back the GC row on PressureWasherTorquePage; GC160/GC190 still have no entry in this dataset and should get a proper one rather than being inferred from the GCV rows below.

Honda GCV160160cc Manufacturer-published

Fastener torques are from Honda's official "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet, which explicitly names… More about this engine ›

GCV160 in its one shared torque table (the sheet does not print separate numbers per model in this family). Valve clearance is cross-applied from the GCV190 shop manual's maintenance-standards table (same core architecture) and flagged medium confidence for that reason. GCV160 has no oil drain-plug bolt -- oil is drained by tilting the engine with the filler cap/dipstick removed. Honda DOES publish a numeric spark-plug torque for this generation: shop manual 61ZM000 prints 20 N-m (14 ft-lb) for the 14x1.25 plug. The owner's manual gives the seat-then-half-turn method instead, which is the same joint by another route; an earlier reading of this file recorded "no published figure" from the owner's manual alone. Note also that the flywheel-nut figures below come from the assembly sheet and are CONTRADICTED by 61ZM000 -- see the conflict note on those rows.

Fastener Torque Where it comes from
cylinder head cover boltM6x12mm (4 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m. GCV135/160/190/GSV190 use a bolt-on valve/cam cover rather than true head bolts -- this is the closest equivalent fastener.
connecting rod bolt 9 ft-lbHigh 12 N-m / 1.2 kgf-m (2 bolts).
flywheel nut (aluminum flywheel)M14x1.5 special nut 55 ft-lbHigh⚠ sources disagree
75 N-m / 7.5 kg-m, per Honda shop manual 61ZM000 (GCV135/GCV160/GCV190/GSV190) TORQUE VALUES table. Why › CONFLICT: Honda's own "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet gives 52 N-m (38 ft-lb) for the same fastener. Both documents are genuine Honda. The shop-manual figure is published here because it is the service specification and because 52 N-m is also exactly the GC/GS family figure (manual 61ZL800), which makes the assembly sheet's number look like a cross-family carry-over. Under-torquing a flywheel nut is the dangerous direction -- it lets the flywheel slip on its taper and shear the key. Check which flywheel you have and use a flywheel holder, never an impact gun.
flywheel nut (cast iron flywheel)M14x1.5 special nut 63 ft-lbHigh⚠ sources disagree
75 ~ 85 N-m / 7.5 ~ 8.5 kg-m (55 ~ 63 ft-lb) per Honda shop manual 61ZM000; the table prints a range; 63 ft-lb is the top of it and is the… Why › number shown here so this row is distinguishable from the aluminum row, but anywhere in 55-63 ft-lb is within Honda spec. CONFLICT: the Honda "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet gives 74 N-m (54 ft-lb) instead. See the aluminum-flywheel row for why the shop manual is preferred.
spark plugM14x1.25 14 ft-lbHigh
20 N-m / 2.0 kg-m per Honda shop manual 61ZM000 TORQUE VALUES table. Why › An earlier reading of this repo recorded "no published figure" because the owner's manual and the maintenance section give the seat-then-turn method instead (thread in by hand to seat the washer, then 1/2 turn more for a new plug, 1/8-1/4 turn if reused). Both are Honda instructions for the same joint. Plug: Honda splits by application -- BPR6ES on pressure-washer applications, BPR5ES on all others; on ACS-equipped engines Honda warns specifically to fit the BPR5ES and not the cooler BPR6ES. Gap 0.7-0.8 mm (0.028-0.031 in).
crankcase cover (oil pan) boltM6x25mm (8 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m. Loosely tighten each bolt, then torque in the numbered 1-8 sequence shown on Honda's diagram.
governor holder shaft boltM6x14mm (2 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m. Minor internal fastener, included for completeness.

Valve clearance — feeler gauge, not a wrench

  • valve clearance (cold), intake: Not a torque spec -- clearance value: 0.15 +/- 0.04 mm. Cross-applied from the GCV190 shop manual's maintenance-standards table (same architecture); not restated under a GCV160-specific heading, so flagged medium rather than high.
  • valve clearance (cold), exhaust: Not a torque spec -- clearance value: 0.20 +/- 0.04 mm. Cross-applied from the GCV190 shop manual (see intake row note).
1 spec not published — engine oil drain plug What we found ›
  • engine oil drain plugN/A -- GCV160 has no drain-plug bolt. Oil is changed by removing the oil filler cap and tilting the engine to drain through the filler neck.

Honda GCV190187cc Manufacturer-published

Fastener torques are from Honda's official "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet, which explicitly names… More about this engine ›

GCV190. Valve clearance and spark-plug gap come from GCV190's own dedicated shop manual (shop-manual-gcv190-en.pdf), which does carry a plain maintenance-standards table even though its procedural "TORQUE" call-out boxes did not survive PDF conversion. Displacement (187cc) is shared with the horizontal-shaft GC190 -- same bore/stroke core engine, though the two families do NOT share a flywheel-nut torque (GC/GS is 52 N-m per 61ZL800; GCV is 75 N-m per 61ZM000). The spark-plug and flywheel rows below are sourced from shop manual 61ZM000; where it disagrees with the assembly sheet the conflict is recorded on the row itself.

Fastener Torque Where it comes from
cylinder head cover boltM6x12mm (4 flange bolts) 9 ft-lbHigh
12 N-m / 1.2 kgf-m. Confirmed twice: the assembly sheet gives the number, and GCV190's own shop manual independently confirms "the four 6 x… Why › 12 mm flange bolts" as the fastener (page 38 of that manual, though its torque box itself is blank).
connecting rod bolt 9 ft-lbHigh 12 N-m / 1.2 kgf-m (2 bolts).
flywheel nut (aluminum flywheel)M14x1.5 special nut 55 ft-lbHigh⚠ sources disagree
75 N-m / 7.5 kg-m, per Honda shop manual 61ZM000 (GCV135/GCV160/GCV190/GSV190) TORQUE VALUES table. Why › CONFLICT: Honda's own "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet gives 52 N-m (38 ft-lb) for the same fastener. Both documents are genuine Honda. The shop-manual figure is published here because it is the service specification and because 52 N-m is also exactly the GC/GS family figure (manual 61ZL800), which makes the assembly sheet's number look like a cross-family carry-over. Under-torquing a flywheel nut is the dangerous direction -- it lets the flywheel slip on its taper and shear the key. Check which flywheel you have and use a flywheel holder, never an impact gun.
flywheel nut (cast iron flywheel)M14x1.5 special nut 63 ft-lbHigh⚠ sources disagree
75 ~ 85 N-m / 7.5 ~ 8.5 kg-m (55 ~ 63 ft-lb) per Honda shop manual 61ZM000; the table prints a range; 63 ft-lb is the top of it and is the… Why › number shown here so this row is distinguishable from the aluminum row, but anywhere in 55-63 ft-lb is within Honda spec. CONFLICT: the Honda "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet gives 74 N-m (54 ft-lb) instead. See the aluminum-flywheel row for why the shop manual is preferred.
spark plugM14x1.25 14 ft-lbHigh
20 N-m / 2.0 kg-m per Honda shop manual 61ZM000 TORQUE VALUES table. Why › An earlier reading of this repo recorded "no published figure" because the owner's manual and the maintenance section give the seat-then-turn method instead (thread in by hand to seat the washer, then 1/2 turn more for a new plug, 1/8-1/4 turn if reused). Both are Honda instructions for the same joint. Plug: Honda splits by application -- BPR6ES on pressure-washer applications, BPR5ES on all others; on ACS-equipped engines Honda warns specifically to fit the BPR5ES and not the cooler BPR6ES. Gap 0.7-0.8 mm (0.028-0.031 in).
crankcase cover (oil pan) boltM6x25mm (8 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m. Numbered 1-8 tightening sequence.
governor holder shaft boltM6x14mm (2 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m.

Valve clearance — feeler gauge, not a wrench

  • valve clearance (cold), intake: Not a torque spec -- clearance value: 0.15 +/- 0.04 mm.
  • valve clearance (cold), exhaust: Not a torque spec -- clearance value: 0.20 +/- 0.04 mm.
1 spec not published — engine oil drain plug What we found ›
  • engine oil drain plugN/A -- GCV190 has no drain-plug bolt. Shop manual: "Tilt the engine toward the oil filler cap side and drain the used oil into a suitable container."

Honda GCV170166cc Manufacturer-published

GCV170 is the newer redesigned platform (not the same architecture as GCV160) -- all values are from Honda's official shop manual for this… More about this engine ›

specific generation (shop-manual-gcv145-170-200-62z9l20-en.pdf), which prints one shared torque table naming GCV170 and GCV200 together, with full N-m/kgf-m/lbf-ft columns. Bore x stroke 60.0 x 59.0 mm, 166cc.

Fastener Torque Where it comes from
cylinder bolt (head equivalent)M8x1.25 (two 8x40mm + two 8x25mm bolts) 18 ft-lbHigh
24 N-m / 2.4 kgf-m. GCV170/200 use a one-piece cylinder casting with a bolt-on valve cover rather than a separate head -- Honda's own torque… Why › table calls this fastener "Cylinder bolt," not "cylinder head bolt."
connecting rod boltM7x1.0 9 ft-lbHigh 12 N-m / 1.2 kgf-m.
flywheel nut (light flywheel type)M14x1.5 41 ft-lbHigh
55 N-m / 5.5-5.6 kgf-m (Honda's own doc prints 5.6 kgf-m once and 5.5 kgf-m once for the same 55 N-m figure -- a minor internal rounding… Why › inconsistency; the N-m and lbf-ft columns agree).
flywheel nut (heavy flywheel type)M14x1.5 55 ft-lbHigh 75 N-m / 7.6 kgf-m.
spark plugM14x1.25 15 ft-lbHigh
20 N-m / 2.0 kgf-m, which Honda rounds to 15 lbf-ft in this manual. Why › The older GCV135/160/190 generation specifies the same 20 N-m in its own shop manual (61ZM000), where Honda rounds it to 14 ft-lb -- the plug torque is one of the few things the two platforms share, so the difference between 14 and 15 here is rounding, not a different spec. Everything else about the two platforms differs; do not cross-apply the rest.
crankcase cover boltM8x1.25 18 ft-lbHigh 24 N-m / 2.4 kgf-m.
rocker arm shaft (valve lifter) boltM6x1.0 7 ft-lbHigh
10 N-m / 1.0 kgf-m. Honda's table lists this as "Valve lifter bolt" -- it retains the rocker arm shaft and is this platform's equivalent to… Why › a "rocker arm pivot bolt."
valve adjusting lock nutM5x1.0 5.9 ft-lbHigh 8 N-m / 0.8 kgf-m.
governor arm nut 9 ft-lbHigh 12 N-m / 1.2 kgf-m. Throttle-governor linkage nut, not a core structural fastener, included because Honda's table lists it.

Valve clearance — feeler gauge, not a wrench

  • valve clearance (cold), intake: Not a torque spec -- clearance value: 0.08 - 0.12 mm (0.003 - 0.005 in). Same value for intake and exhaust on this platform (unlike GCV160/190, which differ by valve).
  • valve clearance (cold), exhaust: Not a torque spec -- clearance value: 0.08 - 0.12 mm (0.003 - 0.005 in). Same as intake on this platform.
1 spec not published — engine oil drain plug What we found ›
  • engine oil drain plugN/A -- no drain-plug bolt is listed in the torque table or the oil-change procedure; oil is changed by tilting the engine and draining through the oil filler neck/dipstick opening, same as GCV160/190.

Honda GCV200201cc Manufacturer-published

Same official shop manual as GCV170 above (shop-manual-gcv145-170-200-62z9l20-en.pdf); Honda prints one shared torque table for… More about this engine ›

"GCV170/GCV200" with identical fastener values for both displacements -- only the bore (66.0mm vs 60.0mm), sleeve/piston dimensions, and governed-speed specs differ between the two engines. Bore x stroke 66.0 x 59.0 mm, 201cc.

Fastener Torque Where it comes from
cylinder bolt (head equivalent)M8x1.25 (two 8x40mm + two 8x25mm bolts) 18 ft-lbHigh 24 N-m / 2.4 kgf-m. Identical figure to GCV170 -- Honda's table does not split this value by displacement.
connecting rod boltM7x1.0 9 ft-lbHigh 12 N-m / 1.2 kgf-m.
flywheel nut (light flywheel type)M14x1.5 41 ft-lbHigh 55 N-m / 5.5-5.6 kgf-m.
flywheel nut (heavy flywheel type)M14x1.5 55 ft-lbHigh 75 N-m / 7.6 kgf-m.
spark plugM14x1.25 15 ft-lbHigh 20 N-m / 2.0 kgf-m.
crankcase cover boltM8x1.25 18 ft-lbHigh 24 N-m / 2.4 kgf-m.
rocker arm shaft (valve lifter) boltM6x1.0 7 ft-lbHigh 10 N-m / 1.0 kgf-m.
valve adjusting lock nutM5x1.0 5.9 ft-lbHigh 8 N-m / 0.8 kgf-m.

Valve clearance — feeler gauge, not a wrench

  • valve clearance (cold), intake: Not a torque spec -- clearance value: 0.08 - 0.12 mm (0.003 - 0.005 in).
  • valve clearance (cold), exhaust: Not a torque spec -- clearance value: 0.08 - 0.12 mm (0.003 - 0.005 in).
1 spec not published — engine oil drain plug What we found ›
  • engine oil drain plugN/A -- no drain-plug bolt; oil is changed by tilting the engine and draining through the oil filler neck.

Honda GSV190187cc Manufacturer-published

GSV190 is a higher-output governor variant of the same GCV190 core engine (construction/pump/commercial equipment rather than mowers)… More about this engine ›

documented on the identical "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" sheet, which names GSV190 explicitly in its title. Included as a bonus entry since it shares the exact same shared torque table as GCV160/GCV190 above -- including the flywheel-nut figures, which come from shop manual 61ZM000 (75 N-m aluminum, 75~85 N-m cast iron) and are contradicted by the assembly sheet. See the conflict notes on those rows.

Fastener Torque Where it comes from
cylinder head cover boltM6x12mm (4 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m.
connecting rod bolt 9 ft-lbHigh 12 N-m / 1.2 kgf-m (2 bolts).
flywheel nut (aluminum flywheel)M14x1.5 special nut 55 ft-lbHigh⚠ sources disagree
75 N-m / 7.5 kg-m, per Honda shop manual 61ZM000, whose title covers GSV190 alongside GCV135/160/190. Why › CONFLICT: the "GCV135 - GCV160 - GCV190 - GSV190 Engine Assembly" information sheet gives 52 N-m (38 ft-lb) for the same fastener. Both documents are genuine Honda. The shop manual is followed because it is the service specification and because 52 N-m is exactly the GC/GS family figure from manual 61ZL800, i.e. very likely a cross-family carry-over. Under-torque is the dangerous direction on a flywheel taper -- it lets the flywheel slip and shear its key.
flywheel nut (cast iron flywheel)M14x1.5 special nut 63 ft-lbHigh⚠ sources disagree
61ZM000 prints a RANGE for the cast-iron flywheel: 75~85 N-m (7.5~8.5 kg-m, 55~63 ft-lb). Why › 63 ft-lb is the top of that range and is shown here so this row is distinguishable from the aluminum row; anywhere in 55-63 ft-lb is within Honda spec. CONFLICT: the engine-assembly information sheet gives 74 N-m (54 ft-lb) instead -- see the aluminum-flywheel row for why the shop manual is preferred.
crankcase cover (oil pan) boltM6x25mm (8 bolts) 9 ft-lbHigh 12 N-m / 1.2 kgf-m.

Honda GCV530 (V-Twin) Manufacturer-published

Optional/bonus entry -- larger commercial V-twin, shares its shop manual and assembly sheet with the GXV530. More about this engine ›

Sourced from Honda's official "GCV530 - GXV530 Engine Assembly Information" sheet. This is a structurally different engine from the GCV160-200 singles above: it has 4 connecting-rod bolts (2 cylinders), 8 cylinder-retaining flange nuts, and -- unlike every single-cylinder GCV above -- a genuine 20mm crankcase oil-drain bolt on equipped models.

Fastener Torque Where it comes from
cylinder-to-crankcase flange nut (head equivalent)8mm flange nut (8 total, 4 per cylinder) 24 ft-lbHigh 32 N-m / 3.3 kgf-m.
connecting rod bolt 9 ft-lbHigh 12 N-m / 1.2 kgf-m (4 bolts total, 2 per connecting-rod cap).
flywheel/starter-pulley bolt16mm 116 ft-lbHigh
157 N-m / 16.0 kgf-m. The V-twin uses a large central through-bolt rather than the single-cylinder GCV's 14mm nut -- do not confuse this… Why › with the 41-63 ft-lb GCV160-200 flywheel-nut figures.
oil drain bolt (equipped type only)20mm 33 ft-lbHigh 44 N-m / 4.5 kgf-m. Unlike the single-cylinder GCV160-200, GCV530/GXV530 does have a dedicated crankcase drain bolt on equipped models.
crankcase cover (oil pan) boltM8x40mm (7 bolts) 17 ft-lbHigh 24 N-m / 2.4 kgf-m. Loosely tighten, then torque in the numbered sequence.
valve adjusting lock nut 5.4 ft-lbHigh
7.5 N-m / 0.75 kgf-m (4 nuts total, 2 per cylinder). Why › Genuinely lower than the single-cylinder GCV170/200's 8 N-m figure -- not a typo, a different published spec for this engine.
oil filter (equipped type only) 9 ft-lbHigh 12 N-m / 1.2 kgf-m, per Honda's torque-wrench spec for filter installation (not a hand-tighten-only spec on this engine).
2 specs not published — cylinder head cover bolt, spark plug What we found ›
  • cylinder head cover bolt6x12mm (8 bolts shown on diagram)GAP: the diagram shows "6 x 12 (8)" head-cover bolts but no torque figure was legible adjacent to that callout in Honda's document -- do not assume it matches the single-cylinder GCV's 12 N-m figure.
  • spark plugGAP: plug type given (BPR5ES NGK / W16EPR-U Denso) but no numeric install torque found in this document.

What is the head/cylinder-cover bolt torque on a Honda GCV160 lawn mower engine?

12 N·m (9 ft-lb) on the M6x12mm valve-cover bolts, per Honda's official GCV135/160/190/GSV190 engine-assembly sheet. Note this is a different, newer-generation engine than the GCV170/200 (see below) -- do not mix up the two tables.

What is the head bolt torque on a Honda GCV170 or GCV200 (found in many HRX/HRN mowers)?

24 N·m (18 ft-lb) on the "cylinder bolts" (two 8x40mm + two 8x25mm, M8x1.25), per Honda's official GCV145/170/200 shop manual. GCV170 and GCV200 share the exact same torque table despite the different bore size.

How do I drain the oil on a Honda GCV mower engine -- where is the drain plug?

There isn't one. Every GCV160/170/190/200 engine drains through the oil filler neck: remove the filler cap/dipstick and tilt the engine so oil pours out that opening. This is confirmed directly in Honda's owner's and shop manuals for both the older (160/190) and newer (170/200) generations -- if you're searching for a drain bolt torque spec, it doesn't exist because the part doesn't exist on these engines.

What torque do I use to install a spark plug in a Honda GCV mower engine?

Honda's GCV shop manual (61ZM000) specifies 20 N·m — 14 ft-lb — for the 14x1.25 plug on the GCV135/160/190 and GSV190. The owner's manual gives an equivalent method instead: seat the washer finger-tight, then 1/2 turn more for a new plug (1/8-1/4 turn if reusing one). GCV170/200 is a different platform and Honda publishes 20 N·m there too, which it rounds to 15 ft-lb.

What is the flywheel nut torque on a Honda GCV mower engine?

GCV135/160/190/GSV190: 75 N·m (55 ft-lb) for an aluminum flywheel, 75-85 N·m (55-63 ft-lb) for cast iron, per shop manual 61ZM000. Honda's engine-assembly information sheet prints lower figures for the same fastener (52 N·m / 74 N·m); where the two disagree this site follows the shop manual, and 52 N·m is in any case the GC/GS family's figure rather than the GCV's. GCV170/200: 55 N·m (41 ft-lb) light flywheel, 75 N·m (55 ft-lb) heavy flywheel. Always use a flywheel-holding tool, never an impact gun.

Are GCV160 and GCV170 the same engine with different torque specs, or completely different designs?

Different designs, not just different numbers. GCV170/GCV200 are Honda's newer redesign of this displacement class -- different cylinder/head architecture (a one-piece "cylinder bolt" cover rather than a separate valve cover, and real M8 cylinder bolts where the GCV160/190 has none at all), a different flywheel-nut spec, and its own dedicated shop manual. The spark plug happens to land on the same 20 N·m in both generations, but that is a coincidence of plug size rather than a shared spec. Don't cross-apply GCV160/190 numbers to a GCV170/200, or vice versa.

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