LY2A Series Shaftdrive 370-440mhp

Power Boat Engines

Yanmar LYA Series Marine Diesel Engine (370 – 440hp)

Engine Model

  • 6LY2A-UTP     370mhp @ 3300rpm
  • 6LY2A-STP    440mph @ 3300rpm

Gear Option

  • KMH61A (Down Angle 8°)  Ratio 1.55 / 2.04 / 2.43
  • KMH61V (Intergral 12°)  Ratio  1.24 / 1.49 / 1.98 /2.48

High performance straight six

For boats, the ability to slot an engine as low down as possible, or to mount twin engines low in the vee of the boat has been critical. The straight six has thus become the configuration of choice, as the crankshaft is still not as long as to require heavy strengthening, there is more capacity advantage over a four, and a six is far narrower than a vee-eight.


The mountability is excellent due to its flat top, and due to its narrow profile. Repowering a gasoline engine boat is now a pleasure, for this engine has more muscle and endurance to match virtually whatever was previously being used.


  • Endurance and fuel economy
  • More Power and more speed
  • Excellent economy with superb performance
  • Relibility

Race proven performance is inherited. Power-to-weight ratio is even more startling. Endurance and fuel economy are at a level that only a diesel could achieve.

It follows current user trends, ie the demand for more power and more speed. And because it is a diesel, smaller fuel tanks can be used saving hundreds of kgs of weight in a fast boat. A speed increase becomes immediately possible.

Direct injection using ultra-high-pressure fine mist injectors makes for excellent economy together with superb performance, yet there is minimal smoke under hard use conditions. Fuel savings, precious energy savings, and an increase in safety accompany the change to a diesel.

All service points are conveniently placed high on the engine. Renowned Yanmar reliability and parts backup complete the package. An engine that will dramatically lift the performance of virtually ANY hull, and likely put you in the race winners seat, if you so desire.



  • Flexible engine mount, 4 pcs/set


  • Exhaust water mixing elbow, L-Type
  • Air vending device for cooling water tank (for V-drive)


  • Lube oil dipstick for opposite side of engine

Starting and stopping

  • Electric engine stop solenoid

Electrical and Instrumentation

  • New D-type instrument panel
  • Meter sensor assy for New B, C & D-type panel
  • Extension wireharness, 6m



  • Propeller shaft half coupling for KMH61A1 (Straight rough bore)


  • Fuel/water separator


  • Kingston cock, 45A
  • Exhaust water mixing elbow, Riser type


  • Lube oil evacuation pump, rotary type

Starting and stopping

  • Cold starting aid (Air heater type)

Electrical and Instrumentation

  • Electric type bilge pump, 12V
  • New B-type instrument panel
  • New C-type instrument panel
  • Meter sensor assy for dual instrument panel (New C+C or C+D type)
  • Connection wireharness for dual instrument panel


  • Side-mount type single control head (MORSE:MV)
  • Top-mount type single control head (MORSE:MT3)


  • Onboard tool kit







Power Profile

Media Release