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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: 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.