DSI – Reporting for Duty!

The all-new Mercury DSI Outboard.

I am excited to share with you information regarding our second “stealth” outboard that will be rarely seen; the DSI (Diesel Spark Ignited) Outboard.

Our latest military engine was released 10:00 a.m. Eastern time in conjunction with the start of the 2015 SOFIC (Special Operation Forces Industry Conference), May 19-21, in Tampa. The engine, displayed in a booth we shared with our OEM boat builder partner MAPC (Maritime Applied Physics Corporation), is  the talk of the show.

The Diesel Spark Ignited Outboard was designed and developed by Mercury Racing.

Developed for the U.S. Department of Defense (DoD), this exclusive spark ignited, direct fuel injected 2-stroke runs on ultra-low sulfur diesel fuel, which is readily available around the globe. Mercury Government Accounts Manager Tony Nahitchevansky explains the history behind the development of our latest military engine.

“A Navy ship crash in 1995, which resulted in an explosive gasoline fire, spawned a DoD directive for all gasoline powered engines and gasoline fuel tanks be removed from Naval ships by 2010,” The mandate called for engines to be developed to operate on fuels that meet the following criteria:

1) Improve ship safety by minimizing fire hazards,

2) More economical and more efficient, and

3) Readily available as a single battle space fuel.

The 3.0 Liter V-6 Diesel, which produces 175 propshaft horsepower, shares 95 percent of its components with the gasoline engine from which it derives. And, with only a handful of unique parts, there are minimal additional training requirements necessary for maintenance.

Industry Exclusive Direct Fuel Injected – Spark Ignited Diesel

A cutaway view of our industry exclusive spark ignited diesel cylinder head.
A cutaway view of our industry exclusive spark ignited diesel cylinder head.

A two-stage, direct-injection system uses a small charge of compressed air to finely atomize the diesel fuel as it injects into the combustion chamber. Atomizing the fuel into a fine mist allows for ignition via spark to occur, while delivering enhanced high rpm running quality. A glow plug works in concert with the spark plug for improved cold weather starting and idle quality.  An on-board Propulsion Control Module (PCM) microprocessor optimizes fuel and spark timing for improved running quality and performance throughout the engine’s operating range. SmartCraft® Engine Guardian provides real-time, self-protection engine fault diagnostics and messaging.

Race Derived Powerhead

The DSI features Verado 400R inspired graphics.

The advanced 3.0-liter powerhead, customized with a unique cylinder head designed specifically for combusting diesel fuel, is matched with high performance cylinder liners for maximum horsepower and optimal engine running quality.

Race Inspired Graphics

The DSI features stealthy, tone-on-tone graphics that feature the new Mercury Racing word mark – similar to those featured on the new Racing Verado 400R consumer performance outboard models. Mercury Racing DSI outboards are available with a 25-inch (635 mm) center section and a 2.08:1 gearcase in both right-hand and left-hand rotation.

 

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130 thoughts on “DSI – Reporting for Duty!”

  1. Sweet motor you have there, i wonder if this is good for the North in canada? Howmuch for the motor?

    1. Hi Perry:
      The OptiMax Diesel is specifically for military use and not available for the general public.
      Rick

      1. We had an optimax135 idling on diesel at a service school back in 1998. The only way you knew it was running on diesel was the exhaust smell

        1. Now that is does exist, it SHOULD be available to us as well because it would add immensely to our safety when at sea
          ….methink…

          1. Hi John:
            The DSI was first requested by the US Department of Defense. They are currently validating it for their needs. We may consider a commercial model in the future.
            Rick

          1. J,
            The DSI was first requested by the US Department of Defense for military. They are validating the product for their needs. It will first be released for their exclusive use. We may consider offering a commercial model in the future.
            Rick

          1. Marco:
            The DSI is under validation by the U.S. Navy. We are exploring other markets for it now. We will keep you abreast as to when it will be available.
            Rick

      2. Dear Rick Machie,
        We are PSSEA VIETNAM CO.,LTD from Hanoi city, Vietnam. We are specialized in importing marine equipment to Vietnamese market.
        May we know followings about your O/B diesel engine Mercury 175HP?
        Incl.
        1. Unit price per set (CIF BUSAN, KOREA – because our boat will be made in Korea before its delivery to Vietnam).
        (*) In case our order will be over ten (10) engines. What is the best price?
        2. Soonest delivery time.
        3. After-sales service (spare parts with reference price list).
        If agreed, we (or our boat maker in Korea will be appointed) will sign order directly with you .
        The order can be started right after your good feed back.
        Thanks in advance,
        Hai, Luu Xuan (Mr.)/General director
        Email: giahung2510@gmail.com

      3. why not ???
        this technology deserves to be extended to all commercial duty outboard engines, 175 HP is relatively big engine but this can be extended to smaller engines as the cost of development can be absorbed by a much high number of engines produced.

      1. Stevens;
        MSRP for Diesel Outboards is $27,293 for the right-hand model; $27,348 for the left-hand model.
        Rick

        1. Nuts. If shares 95% of common parts with the gasoline counterparts, why not 5% more costly than the gasoline?
          It is priced on purpose not to be purchased by 99% of the market.
          My 2 cents…..

    2. Perry
      That is a very good diesel outboard engines that our military needs.
      please give us quote, (CIF), for your fast interceptor craft/boats with the following parameters:

            a.       Length overall (LOC) = 11.7, 12.0, 14.0, up to 17.0 meters with firm fore and aft boards for mounting of machine guns
            b.      Craft should be able to withstand force three to four sea conditions
            c.       Craft  should be diesel outboard engines 350-450HP
            d.      Confirmation as to availability of craft on the shelf, including minimum delivery date to Nigeria, West Africa

      Quote to include two years recommended backup spares and accessories.

      Please forward relevant brochures for necessary information. Kindly treat with dispatch.

      Elder R.A Ikediashi
      MD
      Riverline Agencies Nigeria Limited
      Tel. +234-806-591-2054
      Email. riverline_ag@yahoo. com.

    3. Dear Rick Machie,
      We are PSSEA VIETNAM CO.,LTD from Hanoi city, Vietnam. We are specialized in importing marine equipment to Vietnamese market.
      May we know followings about your O/B diesel engine Mercury 175HP?
      Incl.
      1. Unit price per set (CIF BUSAN, KOREA – because our boat will be made in Korea before its delivery to Vietnam).
      (*) In case our order will be over ten (10) engines. What is the best price?
      2. Soonest delivery time.
      3. After-sales service (spare parts with reference price list).
      If agreed, we (or our boat maker in Korea will be appointed) will sign order directly with you .
      The order can be started right after your good feed back.
      Thanks in advance,
      Hai, Luu Xuan (Mr.)/General director
      Email: giahung2510@gmail.com

      1. Hai, Luu:
        I cannot quote anything to you. I suggest you visit your local authorized Mercury Outboard dealer/distributor who will be able to provide you DSI pricing and availability.
        Rick

  2. OH MY GOD !!! Call/write when you need someone in Dunnellon, Florida to OPS Check this thing.. Ret. USAF and loving retirement with plenty of fishin time…

    1. Sam;
      The OptiMax Diesel was developed specifically for the U.S. Department of Defense. It is not available for the general public and or for recreational boating. With your credentials, however, we will keep you in mind should we need some additional development time put on the engine.:) Thank you for serving our country.
      Rick

    1. Hello Fernando:
      The OptiMax Diesel is a military engine developed specifically for the U.S. Department of Defense. It is not available for the general public or for recreational boating use.

    1. Hi Kris:
      The OptiMax Diesel was developed specifically for the U.S. Department of Defense and will only be available for their use.
      Rick

  3. It’ll be interesting times ahead for Mercury that’s for sure , I myself can’t wait to see how the performance is on these motors and the weight factor.

    1. Paul.
      Yes. Exciting times now and into the future for Mercury Marine and Mercury Racing. Look for some major OptiMax Diesel performance test articles to be published later this year.
      Rick

  4. FELICITACIONES,
    ESTO FORTALEZE MAS A MERCURY DENTRO DE LA INDUSTRIA MARINA
    ME GUSTARIA RECIBIR MAS INFORMACION DEL MOTOR,
    TABLAS DE RENDIMIENTO DE COMBUSTIBLE,
    CONSUMO,
    AUTONOMIA,
    ACELERACION,
    RUIDO
    CUANTO TIEMPO DE GARANTIA
    MANTENIMIENTO A LAS 100 HORAS ?
    MANTENIMIENTO PREVENTIVO A CUANTAS HORAS

    GRACIAS

    MARCOS LINDO
    MERCURY CMCA
    OFFICE MEXICO

    1. Hi Chris.
      The OptiMax Diesel is 175 hp at the propshaft. Weight is 517 lbs. The Diesel is a military engine developed for the U.S. Department of Defense. It is not available for the general public.
      Rick

  5. Can you please email me more info so I may teach this new technology to my students. We have 35 Mercury outboards in our high school Marine Tech program. We are in the Florida Keys and have over100 students in it at Coral Shores High School. Thanks and this is great news.

    1. Hi Chris,

      Could you send me a copy of the same information? I am marine mechanic and I would like to learn more about this motors.

      Regards
      Alvaro

  6. Pingback: Optimax 3.0 Diesel
    1. Hi Scott:
      The OptiMax Diesel will be released for sale to the U.S. Navy later this year. It features a mechanical control system.
      Rick

    1. Both of our military spec outboards are based on the 3.0 Liter V-6 – OptiMax direct fuel injected 2-stroke powerhead. OptiMax JP, a multiple fuel engine that can burn JP5, JP8 and Jet-A fuels, produces 185 propshaft horsepower. The Diesel – which burns ultra low sulpher #2 diesel fuel, produces 175 propshaft horsepower.

    2. Hi John:
      Both of our military spec outboards are based on the 3.0 Liter V-6 – OptiMax direct fuel injected 2-stroke powerhead. OptiMax JP, a multiple fuel engine that can burn JP5, JP8 and Jet-A fuels, produces 185 propshaft horsepower. The Diesel – which burns ultra low sulpher #2 diesel fuel, produces 175 propshaft horsepower.
      Rick

    1. Hi Daniel:
      What specific additional information are you interested in? Are you wanting more information on the Diesel Outboard specifically or other Mercury Racing products?
      Rick

    1. Hi Steve.
      Thanks for your interest.
      The OptiMax Diesel is a military spec engine. It is not available to the general public.
      Rick

    1. Hi Chris.
      Thanks for your compliment. Unfortunately, the OptiMax Diesel will only be available for the U.S. Military.
      Rick

  7. I am not going to be redundant and ask when this military spec motor will be available to consumers. I will ask are you working on a consumer model for the public?
    Eric

    1. Hi Eric.
      The OptiMax Diesel currently does not meet U.S. EPA exhaust emissions regulation requirements. That is the main reason it will not be available as a consumer engine. However. We are constantly refining our products. If we find we can meet the emissions standards in the future then it is possible the OptiMax Diesel could be added to our family of high performance consumer outboards.
      Rick

  8. since this was developed for the U.S. Military is it exempt from the EPA standards for Diesel engines? Does that exemption have anything to do with why it is not available to the general public?

    1. Hi Andy;
      Yes. The OptiMax Diesel currently doesn’t meet U.S. exhaust emissions regulations requirements and thus the main reason it will not be available as a consumer model. We are constantly refining our products so that could change in the future.
      Rick

  9. Do you think that mercury will ever consider releasing this motor for public use??? Seems that there is some major public interest in it!!! If one happens to fall off the back of a Naval boat, send me the GPS coordinates!!!

    1. James;
      Make sure your GPS device is up to date. You never know when you might get the call.:) Your right. The response to our OptiMax diesel outboard release has been phenomenal. It doesn’t currently meet EPA emissions regulation requirements which is the main reason it is not going to be available to the general public for recreational boating. We are constantly refining our products and thus there could be a time when you could see them on public waterways.
      Rick

    1. Hi Ron,
      Interesting concept. We did have a part (actually two – equating to a pair of M8 steer drives and transmissions for Cigarette Racing’s concept AMG electric performance boat).
      Rick

  10. Hi Rick
    I guess I’ll have to be the guy to ask the question, you, no doubt, will NOT answer. “only to the military” Why?

    1. Hi Brian.
      Good question. The OptiMax Diesel currently doesn’t meet U.S. EPA emissions regulations and thus can not be sold to the general public for recreational boating.
      Rick

  11. If Mercury doesn’t sell it to the general public, you know what is going to happen. The Japanese will copy it, and it will be for sale through Honda and Yamaha within 2 years.

    1. Hi Stu:
      The engine currently does not meet U.S. EPA or EU emissions regulation requirements. We are continually refining our product and thus it is possible a consumer version of the OptiMax Diesel could see the light of day. It is first being developed for military use of which emissions requirements are not as critical as they are in general recreational use.

      1. Figures.

        That said, how do I find MSRP on your diesel inboards? I am repowering a 26′ inboard. and interested in your 260hp or 370. Are these based on the VW engine? I am also comparing the Hyundai Seasall.

        I do not want an outdrive. I’ll connect a velvet drive to it.

        Thanks.

        1. Hi Mike:
          You should see your local Mercury MerCruiser dealer who can provide you with pricing and availability on all of our diesel engines.
          Rick

  12. Curious from technical point of view – how many RPM does this motor run at? Does it perform like a diesel engine with lots of low end torque and a big torque rise or does it run more like a gas engine characteristic but just running on alternative fuel??

    Thanks

    1. Hi James:
      The engine operating range for the OptiMax Diesel is 5000 to 6000 rpm. It is based off the 3.0 Liter direct fuel injected OptiMax platform and thus it behaves more like the 2-stroke gasoline engine it was derived from versus a typical 4-stroke diesel engine.

  13. Hi.
    This is just what we have been looking for years and years over here in Norway! You really need to go further on and release this for the European market! Over here we have really too expensive fuel, but for diesel for boat use, we pay lower tax. I want this motor!

    1. Hi Robert:
      Thank you for your kind remarks regarding the diesel. The engine currently doesn’t meet U.S. or EU emissions requirements today. We are continually refining our products and so perhaps it could meet emissions requirements in the future.
      Rick

    1. Hi Greg.
      The Diesel is first being offered for the U.S. Department of Defense. We are continually working on development and reviewing the emissions output. It is possible it could one day meet U.S. emissions standards which would enable us to offer it for use in commercial/receational applications.

  14. Rick,
    Do you run conventional fuel and air pressures like the Pro XS or are the pressures higher? How about compression ratio? Does the engine spark at all times, is it ever a “real diesel”? One more question, why develop the Opti vs. the Verado, I would have guessed that the forced induction would benefit the diesel a touch more?
    Kudos to the Racing Dept on another win!!

    1. Hi Brent.

      The OptiMax Diesel utilizes the same fuel pressure (110 psi) and air pressure (95 psi) as our OptiMax 250 SportXS or 300XS. The Compression ratio is about 2 points lower than a gas Opti. The engine is unique in that it is truly a “spark ignited diesel,” versus glow plug. The glow plug assists the spark ignition by warming the combustion chamber sufficiently for enhanced vaporization of the fuel. This is particularly needed in cold weather. Good question regarding platform choice; direct fuel injected 2-stroke vs 4-stroke (Verado). The stratified charge plume of the Opti combustion system is the key to getting the diesel fuel to a consistent, ignitable mixture.

      Rick

      George

  15. Can this be sold on boats to the Norwegian Navy?
    If so please contact me as I’m developing a super efficient hull where a dual installation of these would fit the bill perfectly.

    1. Espen:
      The Diesel is first being developed for the U.S. Department of Defense. I would imagine it will be made available for other military applications in the future.

  16. I’m not surprised that it doesn’t meet emissions requirements. The two cycle Detroit’s didn’t meet it either and the military used the hell out of those. By design, a two cycle engine always lets “some” unburned toxins into the atmosphere. It is interesting that the gasoline version is still available for sale in the states though. Do the original versions get a more complete burn based on the volatile characteristics of gasoline?

    1. Hello Aaron:
      Yes. The OptiMax family of 2-stroke gasoline engines meet both EPA and CARB emissions standards.
      Rick

  17. Hi,
    I completely agree with Robert the Norwegian, as fuel prices are way to high in Europe due to tax purposes. I wish Mercury all the best in bringing this technology forward. Be on the outlook for Yamaha and Honda taking this concept into the recreational market.

    1. Hi Sollie:
      Thanks for your kind comments. We’ll keep you abreast of the Diesel development and emissions compliance progress.

    1. Gerry;
      I can only provide MSRP pricing;
      $27,293 for the right-hand model; $27,348 for the left-hand model.
      Rick

  18. Does this engine use the typical Opti oil system as well? Or does it rely on the better lubricity of diesel to lubricate the engine.

  19. Hi Rick,

    Interesting concept!
    Seems like you guys has been looking into stratified charge to get this working? You will experience to go thru “some” sparkplugs between service intervals though…
    I bet consumption is higher than 176g/kw on your engine? 🙂
    What fuel pump are you using?

    Kind regards,
    Rothor

  20. Is there going to be a release of prop torque ratings for these motors? Always wondered what torque output were on Mercury outboards and any outboard of that matter.

    1. Hi Scott:
      We don’t provide torque data for our outboards. The OptiMax Diesel is a direct injected 2-stroke. The torque is not comparable to a typical four cycle diesel.
      Rick

  21. Pingback: Mercury Diesel
    1. Hi Tyler;
      The OptiMax Diesel is first being validated for the Navy. In its current form – it doesn’t currently meet exhaust emissions standards.
      Rick

  22. Is it better or more powerful than the Pro XS two-stroke; power wise and speed? Also, is it quiet? How much torque does it produce when compared to the OptiMax Pro XS?
    Thanks,
    Scott

    1. Good questions, Scott. The 3.0 Liter OptiMax Diesel runs very similarly to its gasoline powered cousins. it produces 175 propshaft horsepower, so a little low on power output compared to like displacement – gasoline powered OptiMax Pro XS outboards. The torque is identical and sound levels are very similar.

    1. Hi Colin,
      The fuel requirements we design for (in this case the diesel) were specified by the U.S. Department of Defense.
      Rick

  23. Hi, just saying that this engine is NOT a diesel engine but an engine
    that JUST HAPPENS to runs on heavy oil ( sometimes known as diesel fuel )

    A diesel engine is a compression ignition engine NOT a spark
    ignition engine

    1. Hi Rick,

      Thanks for the reply please do not get me wrong I think the concept of the engine is great.
      It was just that I think calling it a diesel outboard causes confusion as most people will automatically think it is a diesel engine as I did while searching for a diesel outboard for my boat.

      Regards Bob

  24. Look while I am a big fan of diesel outboards, this engine scares me. Why does it share 95% of it’s components with the gasoline version? GM did this with the 350 diesel conversion and it was a horrible mistake. Why is it spark ignited? This seems like a reinvention of the wheel to keep manufacturing costs low. As an owner of Mercury Optis and a diesel truck, I think that the ideals behind the engine are sound, but seems like the follow-through is just to maximize profits from a government contract that could create problems for end users in combat. Sorry if this seems harsh but the marketing behind this engine seems like corners were cut in order to maximize profits.

    1. Hi Chris:
      Unlike traditional diesel outboards which compress fuel to the point of ignition, Our 175 h.p. DSI (Diesel Spark Ignition) is the only outboard in the world that ignites diesel fuel with a spark plug. Glow plugs are present to help bring the cylinder head up to the proper temperature for combustion to take place. The use of our proven 3.0 Liter OptiMax powerhead and related components not only helps with power-to-weight but it also enables the engine to be serviced by an authorized Mercury Outboard dealer anywhere in the world.
      Rick

  25. Sorry but you haw invented the wheel again.
    This type of Diesel engine was invented in Sweden by Jonas Hesselman and was introduced 1925 .
    It was caled the Hesselmanengine and it was a combo between Otto engine and Diesel engine, Just like this engine

  26. I currently have a single engine Diesel. I’d love to have the engine removed and put three of these on an armstrong bracket with on my 32 boat.

    I know they do not meet rec emissions…however…is there even a good chance we could see a diesel opti make it to the public?

    1. Hi Frank;
      The DSI (Spark Ignition Diesel) outboard is available strictly for military or commercial applications.
      Rick

  27. Is this motor available to the general public yet? I am currently building a 53′ houseboat and would like to use diesel outboards for safety purposes.

    1. Hi Danny;
      No. The 175 h.p. DSI (Diesel Spark Ignition) outboard is available only for Military or Commercial applications.
      Rick

  28. Mr. Mackie,
    Forgive me if you’ve already answered this question, but are there variations of this diesel outboard with greater than 175 h.p.? And yes, I understand the diesel model is only available to DOD at this time.
    Thanks.

    Thomas

    1. Hello Thomas.
      The 3.0 Liter DSI (Diesel Spark Ignition) outboard is available is for both commercial and government applications. both models are 175 horsepower.
      Rick

  29. JUST GET ME A MOTOR, Ill make it meet emmissions… but it will need a differernt cowl and MAP sensor when i get done..

  30. Hi Rick,
    We are commercial boat builders and coast guard boat builders here in India!
    We need 2 and/ or 3 diesel outboard engines per vessel that we build!
    We would be happy to get more details in respect to its weight, length of shaft , options, hydraulic lift etc, and bulk engine prices for such engines!
    We have been in touch with your India Distributors for this too- kindly keep us advised!
    Many thanks- Ramesh Kundanmal.

    1. Ramesh:
      That is exciting news! Yes – please provide addtional information regarding your boats to our distributor. You can find addtional information on the DSI here.

    2. Hi Rick,
      I am outboard dealer in Italy and I use to service Boats and Ribs from Coast Guard. They recently asked me about diesel outboards. Is it possible a contact?

  31. Hi Rick,

    Your diesel outboard engine is a very exciting product !
    Working for a French shipyard that makes naval vessels and exploration cruise ships, your engine can be very usefull for us.
    I understand that the engine is not EPA, not EU compliant. It is probably not IMO Tier 3 compliant : can you confirm ?
    Can you mail me a ROM price per unit ?

    best regards

    Etienne Beaudet

    1. Hi Beaudet;
      Thanks. Yes. We are very excited about the DSI. The DSI is EPA compliant with a 2-star rating. It doesn’t need to be RCD certified as it for Commercial/Government use only; non consumer applications. See your local Mercury dealer for pricing and availabilty.
      Rick

  32. Hey Rick. I have been a merc fan for a long time and am glad to see you guys breaking into the diesel scene with an outboard. The info on the site says 95% of the parts are the same as the original opti. Does it still use the same air compressor and lubricating system? If so have they reconfigured some of the compressor problems that they had? With the new configuration of pistons and sleeves how many hours do you think they will run before any major repairs? What kind of fuel burn are they getting out of it? Not sure if I’m asking to much seeing as how it is not a consumer product but, I was just curious.
    Good luck with the new product,
    Capt. Paulie Marchan III

    1. Capt. Paulie
      Thank you for your interest. Yes. The compressor and lubrication system is much improved. The DSI uses a stock 3.0 Liter 200 h.p. OptiMax cylinder block which is steel bored. We use custom pistons, rings and heads. It gets very similar run time duration as a std OptiMax and the fuel burn is comparable as well.
      Rick

  33. Rick,

    Need a pair for a busy charter business in the Keys. My mechanic that services my boats works for GMS and he services all of the CBP, Coast Guard, FBI, Dea and Border Patrol vessels. Talk to my prostaff rep Michelle Killbourne and see if we can get a pair of these in real charter use to see what the fuel numbers are along with the day to day operating costs. Let me know. I am looking for a boat that would be perfect to add to the fleet. Thanks, Jason Gabriel Boneafide Charters.

    http://www.boneafidecharters.com
    305.986.3211

  34. Are their any plans for a higher HP model? We are looking for power for a 41 Aluminum Cat and would love to go diesel. Thanks

  35. Are their any plans for a higher HP model? We are looking for power for a 41 Aluminum Cat and would love to go diesel. Thanks, I understand it’s military, but we are a contractor…

  36. Hi,

    we ( me and two students) write a thesis about two stroke engines.
    One Topic includes new technologies. Out of this we found your engine concept. Did you have any puplications for us.
    This would be great and help us to finish our work.
    Thanks in advance
    Best Regards
    Benni, Emre, Seyit

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