Wärtsilä 20

The Wärtsilä 20 has proven its robustness and reliability with over 6000 engines delivered since its introduction to the market in the early 1990s. The engine can switch from MDO to HFO and vice versa without power interruption at any engine operation load.

The Wärtsilä 20 engine is fully compliant with the IMO Tier II exhaust emissions regulations set out in Annex VI of the MARPOL 73/78 convention.


    Exellent fuel flexibility allowing operation on HFO, LBF, MDO and ultra low sulphur fuel. Low fuel oil consumption over a wide load range.

    Utmost power-to-weight and power-to-space rations in combination with a great flexibility in engine support arrangements allows optimised rigid or flexible installation for a wide range of vessel applications.

    High reliability and proven in service makes the Wärtsilä 20 an excellent choice for any application.

    Technical data
    Wärtsilä 20 IMO Tier II or III
    Cylinder bore 200 mm Fuel specification: Fuel oil
    Piston stroke 280 mm 700 cSt/50°C
    Cylinder output 220 kW/cyl 7200 sR1/100°C
    Speed 1200rpm ISO 8217, category ISO-F-RMK 700
    Mean effective pressure 25 bar SFOC 190,0 g/kWh at ISO cond.
    Piston speed 11.2m/s
    Option: Common rail fuel injection.

    Rated power
    Engine type kW/1000rpm  kW/1200rpm
    4L20    800    -
    6L20 1 200 1320
    8L20 1 600 1760
    9L20 1 800 1980
    Dimensions (mm) and weights (tonnes)
    Engine type A* A B* B C* C D F Weight
    4L20    - 2510    - 1348    - 1483 1800 725   7.2
    6L20 3254 3108 1528 1348 1580 1579 1800 624   9.3
    8L20 3973 3783 1614 1465 1756 1713 1800 624 11.0
    9L20 4261 4076 1614 1449 1756 1713 1800 624 11.6

    Wärtsilä 20


    The Wärtsilä 20 can be installed as prime mover for smaller applications like small cargo vessels, small tankers, ferries, Fishing vessels, tug boats and Offshore supply vessels and as Auxiliary engine in vast range of applications.


    • Sten Idun
      Sten Idun is a 16400 dwt Chemical Tanker with a Wärtsilä equipment package of engines, gear and propulsors. Sten Idun vas commissioned 2003 and features a PTI booster and takes me home mode.

      Sten Idun

    • Jeddah 41
      Delivered in 2007, the Jeddah 41 is a 37m Multi Purpose Escort Tug with a 58 tonnes bollard pull. It was designed by Wärtsilä Ship Design to perform escort service, towing and fire fighting.

      Jeddah 41

    • Hirta
      The MPV Hirta, launched in 2008, has a diesel electric propulsion system comprising three Wärtsilä 9L20 engines driving a reduction gear and a controllable pitch propeller.


    • Samar
      The luxury yacht SAMAR was launched in 2006. The ship is powered by a diesel-electric propulsion system consisting of three Wärtsilä diesel generators and two drive motors with twin Wärtsilä fixed-pitch propellers.


    Press releases


    Wärtsilä 20 – Small changes, big results

    We revisit a classic, making it better and more efficient than ever before. The upgraded Wärtsilä 20...
    12 June 2018
    • In Detail article

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