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Yanmar Engine Identification Help

Use this page to help identify your engine model based on year, horsepower and other data. If you do not find your engine listed here you may contact us at: customerservice@torresenonline.com. We will be adding more information to this page often. Let us know what engine you have and we will make it a priority to get your engine listed.

Understanding YANMAR engine model codes

Most engine model designations are on an engine data plate, on the front or the top of the engine. Some older engines have the data plate on the adapter plate between the engine and the gearbox . Here are some examples of engine model codes and their meanings: YSE8 Y= horizontal cylinder, lying down.
SE = engine model type or block type.

8=8 horsepower

If an engine model does not have the Y in the beginning, the engine has a vertical cylinder or cylinders. The numbers 1, 3, 4, and 6 indicate the number of cylinders. For example, 3GM is a 3 cylinder engine with a GM type block. A 2GM is a 2 cylinder engine with a GM type block, and so on.

A 3GM30 is a 3GM that has a larger bore and therefore develops more horsepower than its predecessor. The 1GM, 2GM and 3HM were also uprated to 1GM10, 2GM20 and 3HM35 respectively, note, the suffix numbers are not the horsepower of the engine.

All of the above engines are either 'raw water' cooled or 'fresh water' cooled. An engine with an enclosed cooling system containing fresh water and coolant, in turn cooled by raw water going through a heat exchanger, is a fresh water cooled engine. On engines that are either 'raw' or 'fresh', below 34hp, the fresh water cooled engine has the letter F in the model designation, i.e. a 3HM35F is a freshwater cooled engine. If the F is absent, it is a 'raw' water cooled engine. The JH, LH, LP, LY, CX and KY family of engines are all freshwater cooled. The letter C indicates the engine has a saildrive attached. A 3GM30FC is a 3 cylinder, freshwater cooled engine from the GM family, with a saildrive attached. A 4JH2-BE model is fitted with a down angle gearbox. An M means the engine was shipped from the factory without a gearbox e.g. 6CXM-ETE The 4JH series was uprated to 4JH2 series, then 4JH, series, each series increasing in bore size and horsepower while reducing emission levels to comply with the Bodenzee Regulations in Europe and the EPA / CARB regulations in the USA. 3JH, and 3JH3 versions are also of this family.

The 4LH and 4LHA series are both 4 cylinder engines with the same long block assembled in Japan, but the 4LHA is finally assembled in the USA with US sourced components, the same also applies to the 6LY and 6LYA engines. The models 3JH and over have a suffix in the model code: -E is a normally aspirated export engine

-TE, is a turbocharged, export model engine, -ETE is extra turbocharged -HTE is highly turbocharged, -DTE is deluxe turbocharged

-UTE is ultra turbocharged, -STE is super turbocharged, etc.

When the code has a Z, e.g., 4LHA-STZE, the engine is an inboard outboard model with a Mercruiser sterndrive or 'Z' drive.

Y Series
These horizontal models lay down in a low profile. The series was updated three times with the YSE being the earliest model, followed by the YSB and then the YSM. Either a 2:1 or 3:1 transmission. The models were sea-water cooled, singe cylinder, heavy duty. This series includes the following engines:
EngineHPYears In ProductionComments
YSB12121976 - 1977B=Between
YSB881976 - 1977B=Between
YSE12121974 - 1976E=Early
YSE881974 - 1976E=Early
YSM12121977 - 1980M=Modern
YSM881977 - 1980M=Modern

S Series
Vertical models, updated two times with the SVE engines followed by the SB. Single cylinder, 2:1 or 3:1 transmissions, sea water cooled, heavy duty. This series includes the following engines:
EngineHPYears In ProductionComments
SB12121976 - 1980B=Between
SB881976 - 1980B=Between
SVE12121974 - 1976E=Early
SVE881974 - 1976E=Early

QM Series
The QM series was available either sea-water or fresh-water cooled. 2:1 or 3:1 transmissions. A designation of F near the end of the model means it is fresh-water cooled. F=Factory Fresh Water This series includes the following engines:
EngineHPYears In ProductionComments
2QM - originally only distributed in Japan
2QM15151977 - 19802 Cylinder
2QM20221975 - 1980Engines with serial numbers 0001 - 0030 were prototypes and may require different parts. Engines with serial numbers 80001 - 80930 and 81131 - 81180 were also different from the primary production models and may require different parts. Engines with serial numbers 80931 - 81130 and any serial number higher than 81181 will use standard 2QM20 parts.
2QM20(F)221975 - 19802 Cylinder
2QM20(H)221975 - 19802 Cylinder
3QM - originally only distributed in Japan
3QM30331976 - 19803 Cylinder
3QM30(F)331976 - 19803 Cylinder
3QM30(H)331976 - 19803 Cylinder

GM/HM Series
Introduced in 1980 and 1981 this series was a completely new generation of engines. Lighter, smaller, smoother and quieter than previous engines. An F designation on the model number indicates factory fresh-water cooling. 35 AMP alternators. This series includes the following engines:
EngineHPYears In ProductionComments
1GM7.51980 - 1983Raw
2GM151980 - 1983Raw
2GMF151980 - 1983Fresh
3GM22.51980 - 1983Raw
3GMD22.51980 - 1983.
3GMF22.51980 - 1983Fresh
3HM301980 - 1983Raw
3HMF301980 - 1983Fresh

GM/HM Bored Up Series
Similar to the earlier standard GM/HM series, these engines provide upgraded horsepower and a 55 AMP alternator (1GM10 35 AMP). Special Note: If your engine serial number starts with an "E" you must make sure that you use parts for the YEU engines. For example, if you have a 2GM20 with a serial number starting with E you actually have a 2GM20YEU. The (YEU) engines are European manufactured and now more common in the United States than the Japan built models. This series includes the following engines:
EngineHPYears In ProductionComments
1GM1091983 - 2009Raw Water
2GM20181983 - December 2005Raw
2GM20-YEU181997 - Present
2GM20F181983 - December 2005Fresh
2GM20FYEU18 - .
3GM30271983 - December 2005Raw
3GM30-YEU271997 - Present
3GM30F271983 - December 2005Fresh
3GM30F YEU27 -
3HM35341983 - 1992Replaced with 3JH2
3HM35F341983 - 1992Replaced with 3JH2

YM Series
Completely redesigned cylinder block and new combustion system. Indirect injection, fresh water cooled with heat exchanger, this new engine line complies with ETA Tier 2 and BSO Tier 2. Electric stop solenoid is standard. This series includes the following engines:
EngineHPYears In ProductionComments
2YM1514Fall 2004 - PresentUS Built
3YM2022Summer 2004 - PresentUS Built
3YM3030Summer 2004 - PresentUS Built

JH Series
Extremely smooth running. Two transmission possibilities were available – either a Hurth or 7 degree down angle B type. 80% of the parts for this series of engine are inter-changable since all four engines in the series used the same block. This series includes the following engines:
EngineHPYears In ProductionComments
4JH-DTE771985 - 1989Turbo Charged
4JH-E441983 - 1989
4JH-TE551983 - 1989Turbo Charged
4JH-THE661985 - 1989Turbo Charged

JH2 Series
Extremely smooth running. Horsepower upgrade over the previous JH series. Quiter and cleaner exhaust. A B designation on these engines indicate a down angle transmission. This series includes the following engines:
EngineHPYears In ProductionComments
3JH(B)E381992 - 1999
3JH2-T(B)E471991 - 1999Turbo
4JH2-(B)E511989 - 1999
4JH2-DT(B)E881989 - 1999Turbo-Intercooled
4JH2-HT(B)E761989 - 1999Turbo-Intercooled
4JH2-T(B)E631989 - 1999Turbo-Intercooled
4JH2-UT(B)E1001991 - 1999Turbo-Intercooled

JH3 Series
Upgraded blocks, smaller overall size, smoother and quieter. Meets all new EPA requirements. This series is a replacement of the JH2 series. This series includes the following engines:
EngineHPYears In ProductionComments
3JH340May 1999 - 2004
4JH3-DTBE125Summer 1999 - December 2006Turbo-Intercooled
4JH3-HTBE100Summer 1999 - December 2006Turbo-Intercooled
4JH3-T(B)E75Summer 1999 - December 2006Turbo
4JH3E56May 1999 - 2004

JH4 Series
Redesigned cylinder block and new combustion system. Produces 25% more torque with only a 10% increase in displacement. Lower running speed and less vibration reduce noise by five decibels. Complies with EPA Tier 2 emmissions. This series includes the following engines:
EngineHPYears In ProductionComments
3JH4E39Summer 2004 - Present
3JH4E40Summer 2004 - Present
4JH4E55Summer 2004 - December 2006

LH Series
Extremely compact and lightweight. Very powerful. Transmission is a 7 degree down angle (bi-rotational). Also designed to cleanly replace gas V-8 engines. Larger Hp models. A=Built in USA. Available as both inboard and Mercruiser Stern Drive packages. This series includes the following engines:
EngineHPYears In ProductionComments
4LH-DTE1701990 - 2000Replaces 350 GM
4LH-HTE1401988 - 2000Turbo-Intercooled
4LH-STE230September 1995 - August 1998Replaces 454 GM
4LH-TE1101988 - 2000Turbo
4LHA-DTE190June 2000 - August 2001Upgrade from 170
4LHA-DTZE190Spring 2000 - August 2001Merc I/O Package
4LHA-HTE150Spring 2000 - August 2001Turbo-Intercooled
4LHA-HTZE150Spring 2000 - August 2001Merc I/O Bravo
4LHA-STE230September 1998 - August 2001Waste gated and US built
4LHA-STZE230August 1999 - August 2001Merc I/O Bravo

LY Series
Introduced in 1992, this is the six cylinder version of the 4LH series. Lightweight, compact with excellent horsepower to weight ration. All models are the same size and weight. Smallest HP in its class.

Race-proven performance with startling power-to-weight capability and low-slung configuration. Extremely popular for repowering petrol-driven engines because of the flat-top, narrow profile of these diesels. The engines benefit further from outstanding fuel economy. This series includes the following engines:
EngineHPYears In ProductionComments
6LY-STE350(70)1994 - 1996Turbo-Intercooled
6LY-UTE3151992 - 1996Turbo-Intercooled
6LY2-STE4201998 - Present
6LY2A-STE420March 2001 - September 2001US built
6LYA-STE350January 1997 - May 2001US built
6LYA-STP -
6LYA-UTE315January 1997 - December 2001US built

LP Series
New mini-6 cylinder, super quiet, lightweight, designed for inboard and Merc sterndrive packages. Higher speed (3800 RPM). Many changes from Yanmar's traditional marine models. This series includes the following engines:
EngineHPYears In ProductionComments
6LP250-3001997 - present
6LP-DTZE250January 1998 - September 2001Merc I/O Package
6LP-STE300June 1997 - July 2001Inboard
6LP-STZE300January 1998 - October 2001Merc I/O Bravo
6LPA-DTE250March 2001 - July 2001US built
6LPA-DTP260August 2001 - December 2006Higher Hp
6LPA-DTZE250March 2001 - July 2001US built
6LPA-STE300March 2001 - June 2001US built
6LPA-STZE300March 2001 - June 2001US built
6LPDTE250June 1997 - September 2001Super Quiet/Inboard

CX Series
Heavy duty, super smooth and quietest in this HP class. Commercial model with 4 valves per cylinder. Premium quality. This series includes the following engines:
EngineHPYears In ProductionComments
6CX(M)-ETE4201992 - December 2001Turbo-Intercooled
6CX-GTE465Fall 1999 - December 2005Turbo-Intercooled
6CXM-GTE2500July 2001 - PresentTurbo-Intercooled