Yanmar · Inboard diesel

Yanmar 6LY (6LYA, 6LY2, 6LY3)

The 6LY is Yanmar’s 5.8-litre in-line six-cylinder turbo diesel with a seawater-cooled intercooler for planing motor boats, rated at 3300 rpm and up to 480 mhp, usually with a Kanzaki KMH60A/KMH61A or ZF280 gearbox. The 6LYA (STP, STE, UTE; parts catalogue from 1996) and the 6LY2-STE, 6LY2A-STP (440 mhp) and 6LY2A-UTP (370 mhp; catalogue from 2000) have a mechanical in-line injection pump, while the 6LY3-ETP, STP and UTP (480, 440 and 380 mhp) add electronic engine control with CAN-bus displays and electronic control heads. Filters, impeller, zinc anodes and pressure cap are largely common; thermostat, injectors, turbocharger and head gasket differ between the 6LYA and the 6LY2/6LY2A, and no 6LY3 engine parts catalogue is online, so the 6LY3 numbers here rest on one Yanmar dealer. The original 6LY-STE/UTE and the common-rail successors 6LY400 and 6LY440 have different service parts and are not covered; the smaller six-cylinder 6LP/6LPA shares only a few parts, such as the zinc anodes and the 65 mm intake filter.

Manuals & documents

The links go straight to Yanmar, except the three parts catalogues, which the Yanmar specialist Léon Marine in Sète hosts. Its 6LY3 file covers only the electronic control system: we found no 6LY3 engine parts catalogue online, so the 6LY3 part numbers here rest on one Yanmar dealer. We host no manuals or drawings.

Wear parts & part numbers

PartOEM numberAlso fitsNote
Engine oil filter119593-351001,2,3—Full-flow filter; in Yanmar’s catalogues for the 6LY2-STE, 6LY2A-STP/UTP and 6LYA-STP/STE/UTE. Diesel Parts Direct, a Yanmar dealer, also lists it for the 6LY3 and sells it as 119593-35100-12, which replaces 119593-35100 and 119593-35110.
Bypass oil filter119593-354001,4,5—Second (bypass) filter of the 6LY2-STE and 6LY2A-STP/UTP; the dealer also lists it for the 6LY3, whose manual shows a full-flow and a bypass filter. The 6LYA catalogue shows only the full-flow filter. Dealer stock number 119593-35400-12.
Fuel filter (engine)41650-5023306,7,1,2—Element kit given in the 6LY2A operation manual (2018); Diesel Parts Direct lists it for the 6LY2(A), 6LY3-ETP/STP/UTP and 6LYA-STE/UTE (stock number 41650-502330-12, D90 element). The 2014 parts catalogues for the 6LY2 and 6LYA still show element 41650-550810 in fuel strainer 41650-550310, and no source links the two numbers, so ask your dealer which one they supply for your engine.
Fuel pre-filter120324-557601,2,8—Element for Yanmar’s optional fuel/water separator 120324-55750 (or -55751) on the 6LY2-STE, 6LY2A-STP/UTP and 6LYA. Only if that separator is fitted.
Air filter119593-188801,2,9,6—65 mm intake silencer element of the 6LY2/6LY2A and 6LYA per Yanmar’s catalogues; the dealer also lists the 6LY3-ETP/STP/UTP and the 6LP/6LPA. It is washable: Yanmar says clean it every 250 h rather than replace it.
Raw water pump impeller119574-425521,2,10,6replaces 119574-42550replaces 119574-42551—6LY2/6LY2A and 6LYA: the catalogues went from 119574-42550 to -42551 (October 2006) and -42552 (August 2007). The dealer lists 119574-42552 for the 6LY3-ETP/STP/UTP as well. It comes off with a puller (M24×2 thread, M10×40 jack screw).
Impeller kit (with gasket)119578-4275011—6LY3-ETP, STP and UTP (also STC/UTC), one source: listed by Diesel Parts Direct, contents not itemised. No Yanmar 6LY3 parts catalogue is online to confirm it.
Pump cover O-ring119574-425701,2—End-cover O-ring of the seawater pump; 6LY2-STE, 6LY2A-STP/UTP and 6LYA.
Pump seal kit119578-426001,2—Mechanical seal of the 6LY2/6LY2A and 6LYA pump, a separate spare since September 2010 together with lip seal 119578-42650. Replace it if water keeps leaking from the drain under the pump.
Raw water pump719574-427001,2,12—Complete pump for the 6LY2-STE, 6LY2A-STP/UTP and 6LYA. Diesel Parts Direct supplies 119574-42503 as the replacement for 719574-42700 and 119574-42502 (one source); the catalogues still show 719574-42700.
Alternator V-belt119593-422801,2,13—A53 belt for alternator and coolant pump; 6LY2-STE, 6LY2A-STP/UTP and 6LYA-STP/STE/UTE. Tension: 8–10 mm deflection.
Alternator V-belt119578-4236014—6LY3-ETP, STP and UTP, one source: Diesel Parts Direct. The dealer’s 6LY3 maintenance kits hold two belts; the second one is not confirmed by any source that names the 6LY3.
Thermostat127605-485901,15—71 °C, 6LY2-STE and 6LY2A-STP/UTP only; with gasket 119593-49291. The 6LYA takes a different thermostat (next row).
Thermostat119593-495502,16—76.5 °C, 6LYA-STP/STE/UTE per Yanmar’s catalogue; with gasket 119593-49291.
Thermostat gasket119593-492911,2,17—6LY2/6LY2A and 6LYA, the same for both thermostats.
Anode (engine)119574-187901,2,18—Zinc in the air cooler (intercooler), one on the 6LY2/6LY2A and 6LYA; the same zinc as on the 4LHA and 6LP.
Anode (engine)119574-441501,2,19—Zinc for heat exchanger and oil cooler: two in each on the 6LY2/6LY2A; on the 6LYA the oil cooler takes one from May 2005. The same zinc as on the 4LHA and 6LP.
Pressure cap129107-445901,2—6LY2/6LY2A and 6LYA, on the filler of the exhaust manifold.
Exhaust mixing elbow719578-135001,2replaces 119574-13500—From April 2005 the catalogues replace the original elbow 119574-13500 of the 6LY2/6LY2A and 6LYA with elbow assembly 719578-13500; the 6LYA catalogue shows the change only for the 6LYA-STP.
Exhaust elbow gasket119574-132511,2,20replaces 119574-13250—Gasket between turbocharger outlet and mixing elbow, 6LY2/6LY2A and 6LYA; 119574-13251 since March 2004, which the dealer also lists for the 6LY3.
Fuel injector719575-531001,21—6LY2-STE and 6LY2A-STP built before November 2001; six per engine.
Fuel injector719575-532001,22—6LY2A-STP from November 2001 and every 6LY2A-UTP; six per engine.
Fuel injector719574-532002—6LYA-STP from July 2002; six per engine.
Fuel injector719574-531012—6LYA-STE, and 6LYA-STP before July 2002; six per engine.
Fuel injector719573-531002—6LYA-UTE only; six per engine.
Turbocharger119575-18011 · 119575-180201—IHI RHC7W of the 6LY2/6LY2A. 119575-18011: 6LY2-STE and 6LY2A-STP before November 2001; 119575-18020: 6LY2A-STP from November 2001 and every 6LY2A-UTP.
Turbocharger119574-18012 · 119574-180202replaces 119574-18010replaces 119574-18011—6LYA. 119574-18012 (after -18010 and -18011): 6LYA-STE/UTE and early 6LYA-STP; from July 2002 the 6LYA-STP takes turbo assembly 119574-18020.
Valve cover gasket119593-113601,2—Rocker cover gasket; 6LY2/6LY2A and 6LYA.
Cylinder head gasket119595-013501—1.3 mm (T=1.3), one piece for all six cylinders; 6LY2-STE and 6LY2A-STP/UTP.
Cylinder head gasket119593-013422—1.3 mm (T=1.3); 6LYA-STP/STE/UTE.

Numbers checked against the sources below on 13 October 2026. Always confirm against your serial number and exact type before ordering.

Service intervals

TaskInterval
First service6LY2A: after the first 50 h change engine oil and both oil filters and drain the fuel tank; the dealer checks valve clearance and injector spray at the first 250 h6
First service6LY3: after the first 50 h change engine oil, oil filters and fuel filter element and check the electronic control system; the dealer checks shaft alignment at 50 h and valve clearance and injectors at 250 h5
Engine oil changeEvery 250 h or yearly, first time after 50 h6
Oil filterFull-flow and bypass filter every 250 h or yearly, first time after 50 h6
Fuel filterEvery 250 h or yearly6
Fuel pre-filterDrain the fuel/water separator every 50 h or monthly6
Drain fuel tankEvery 250 h or yearly6
Coolant changeYearly; every 2 years with long-life coolant6
AnodeCheck and replace every 250 h or yearly6
Raw water impeller6LY2A: check or replace every 1000 h or 4 years; replace at 2000 h even if undamaged6
Raw water impeller6LY3: check every 250 h or yearly, replace every 500 h or 2 years5
Air filterClean the intake silencer element every 250 h or yearly6
Exhaust elbow check6LY2A: clean or replace every 250 h or yearly6
Exhaust elbow check6LY3: clean every 250 h or yearly, replace every 500 h or 2 years5
Turbocharger washWash the blower every 250 h or yearly (dealer); on the 6LY3 also flush the air cooler5
V-belt check6LY2A: adjust the tension or replace every 500 h or 2 years6
V-belt check6LY3: check at 50 h and every 500 h, replace every 1000 h or 4 years5
BatteryCheck the electrolyte level every 50 h or monthly6
Valve clearanceFirst at 250 h, then every 1000 h or 4 years (dealer)6
InjectorsSpray pattern first at 250 h, then every 1000 h or 4 years; injection timing every 2000 h (dealer)6
Cooling systemCheck the seawater passages every 1000 h; clean them, the oil cooler and the coolant passages every 2000 h (dealer)6
Hoses & clampsReplace the rubber fuel and water hoses every 2 years6
Engine mounts6LY3: check every 250 h or yearly, replace every 1000 h or 4 years5

From Yanmar’s operation manuals for the 6LY2A (September 2018) and the 6LY3 (April 2018); rows that name no version follow the 6LY2A book. Hours or time, whichever comes first.

Specifications

Cylinders6 in-line, four-stroke, direct injection; Yanmar lists the 6LY3 as a 24-valve engine23
AspirationTurbocharger IHI RHC7W (water-cooled) with seawater-cooled intercooler5,1,23
Displacement5.813 l6
Bore × stroke105.9 × 110 mm6
Power6LY2A-STP: 324 kW (440 mhp) at 3300 rpm, 257 kW (350 mhp) continuous at 3100 rpm. 6LY2A-UTP: 272 kW (370 mhp) under ISO 8665 in the operation manual, while the 2021 datasheet gives 264 kW (359 mhp) under ISO 8665 and 272 kW (370 mhp) under ISO 3046; continuous 213 kW (290 mhp)6,24
Power6LY3-ETP: 353 kW (480 mhp); 6LY3-STP: 324 kW (440 mhp); 6LY3-UTP: 279 kW (380 mhp), at 3300 rpm (ISO 8665). Continuous at 3198 rpm: 436, 401 and 345 mhp5
Rated speed3300 rpm; 6LY3 no-load maximum 3500 ± 25 rpm6,5
Idle speed6LY3: 700 ± 25 rpm5
Injection6LY2A: direct injection with in-line injection pump, mechanical control. 6LY3: electronic engine control with CAN bus (NMEA 2000), multi-function LCD display and electronic control heads24,25
Injection pressure6LY2A: injector opening pressure 27.5–28.5 MPa6
Injection timing6LY2A: FID 15.5 ± 1° before TDC6
CoolingFresh-water circuit with heat exchanger and centrifugal coolant pump; seawater pump with rubber impeller. 6LY3 normal running temperature 71–81 °C5
Engine oil capacity6LY2A: 20 l total, 16.4 l in the oil pan, 8 l between the dipstick marks. 6LY3: 18.8 l total, 8.0 l between the marks6,5
Engine oil grade6LY2A: API CD, CF, CF-4, CI or CI-4, SAE 15W-40. 6LY3: API CD or higher, ACEA E-3/E-4/E-5 or JASO DH-1; SAE 15W-40 recommended6,5
Oil pressure6LY3: 4.0–5.0 bar in normal operation5
Coolant capacity6LY2A: 20 l in the engine + 1.5 l in the reservoir; 6LY3: 28 l + 1.5 l in the recovery tank6,5
CoolantLong-life coolant (LLC) in soft, clean water at 30–60 %6
Alternator6LY3: 12 V 80 A5
Starter motor6LY3: 12 V 3 kW5
Battery6LY3: 12 V, 150 Ah or more5
Dry weight6LY2A: 535 kg without gear, 593 kg with KMH60A; 6LY3: 640 kg without gear6,5
Gearbox6LY2A: Kanzaki KMH60A (8° down angle; 1.55 / 2.04 / 2.43:1) or ZF280-1 / ZF280-1A, flywheel housing SAE #3. 6LY3: Kanzaki KMH61A (8° down angle) or KMH61V; other gears on request24,25
Gearbox oil6LY2A gears: KMH60A 2.8 l, ZF280 4.5 l (API CF or higher, SAE 30)24
Belt tension8–10 mm deflection midway along the belt (about 98 N thumb pressure, per the 6LY3 manual)5
Years built6LYA parts catalogue from April 1996, 6LY2 catalogue from April 2000; the 6LY2A and 6LY3 are still on Yanmar’s product pages2,1,26,27

Good to know

  • The 6LY2 and 6LY2A have two oil filters, a full-flow and a bypass filter: change both at every oil change. The 6LYA catalogue shows only the full-flow filter.1,2
  • Thermostats are not interchangeable between versions: the 6LY2/6LY2A take a 71 °C unit (127605-48590), the 6LYA a 76.5 °C unit (119593-49550). The gasket is the same.1,2
  • The seawater impeller sits tight on its shaft: Yanmar uses a puller with M24×2 thread and an M10×40 jack screw. On the 6LY2A replace it at 2000 h even if it looks fine; on the 6LY3 Yanmar wants a new one every 500 h or 2 years.6,5
  • Zinc plugs are marked ZINC on the heat exchanger, oil cooler and air cooler. Close the seacock first, fit the new zinc in a new plug and do not use thread tape, because the anode needs metal contact.6
  • The mixing elbow bolts straight onto the turbocharger. Clean the scale out of it every year and check the gasket. If the engine loses 10 % or more of its power, have a dealer wash the turbo compressor.6
  • The 6LY3 has electronic engine control: Yanmar asks for a 12 V battery of at least 150 Ah and a daily check of the control system.5

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Sources

  1. leon-marine.com/wp-content/uploads/2021/02/6LY2.pdf
  2. leon-marine.com/wp-content/uploads/2021/02/6LYA-STE-STP.pdf
  3. dieselpartsdirect.com/ym1195933510012
  4. dieselpartsdirect.com/ym1195933540012
  5. yanmar.com/marine/wp-content/uploads/2020/03/0ALY3-EN0013_2018.04.pdf
  6. yanmar.com/marine/wp-content/uploads/2020/03/0ALY2-EN0032_2018.09.pdf
  7. dieselpartsdirect.com/ym4165050233012
  8. dieselpartsdirect.com/ym12032455760
  9. dieselpartsdirect.com/ym11959318880
  10. dieselpartsdirect.com/ym11957442552
  11. dieselpartsdirect.com/ym11957842750
  12. dieselpartsdirect.com/ym11957442503
  13. dieselpartsdirect.com/ym11959342280
  14. dieselpartsdirect.com/ym11957842360
  15. dieselpartsdirect.com/ym12760548590
  16. dieselpartsdirect.com/ym11959349550
  17. dieselpartsdirect.com/ym11959349291
  18. dieselpartsdirect.com/ym11957418790
  19. dieselpartsdirect.com/ym11957444150
  20. dieselpartsdirect.com/ym11957413251
  21. dieselpartsdirect.com/ym71957553100
  22. dieselpartsdirect.com/ym71957553200
  23. yanmar.com/marine/wp-content/uploads/2020/03/Yanmar-Datasheet_6LY3-STP.pdf
  24. yanmar.com/marine/wp-content/uploads/2021/02/DS_6LY2A-UTP-STP_A4_022021_HR.pdf
  25. yanmar.com/marine/wp-content/uploads/2020/03/Yanmar-Datasheet_6LY3-ETP.pdf
  26. yanmar.com/marine/product/engines/6ly2a-stp/
  27. yanmar.com/marine/product/engines/6ly3-etp/

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