Virtual Tour – Part 3: Outboard Production

Continuing from Virtual Tour – Part 2: Quality, Paint, and Quad Cam Production…we will follow the assembly of a Mercury Racing OptiMax 300XS outboard.

2-Cycle Outboards

Gary Aman lowers a 300XS powerhead into position for final engine assembly.
Mike Riedi has over 30 years experience handcrafting high performance gearcases.

Consumer, government and race outboards, featuring Mercury’s low-emissions, direct fuel injected 2-stroke OptiMax powerheads, are assembled at Mercury Racing’s factory in Taycheedah, Wisconsin. Consumer models include the 3.0 Liter OptiMax 250 SportXS and the 3.2 Liter OptiMax 300XS outboards. Watch for a future post on the OptiMax JP, an outboard we build for the government.

The competition outboards produced in Mercury Racing’s factory include our 2.5 Liter OptiMax 200XS SST (Super Stock Tunnel) and 2.5 Liter OptiMax 200XS ROS (Race Offshore). However, Racing’s four strokes — the 60 EFI FormulaRace and the Verado 350 SCi — while designed and validated here, are built off-site at other Mercury facilities in order to share common (and expensive to replicate) production processes.

OptiMax 300XS powerheads await their turn on the dyno.
Mike Hammer inspects each cylinder with a bore scope camera.

OptiMax powerheads are manufactured complete, to Racing’s specifications, at Mercury Marine’s headquarters campus — home to Mercury OptiMax outboard production in Fond du Lac, Wisconsin. Upon their arrival at Mercury Racing, a powerhead’s first stop is one of our 2-cycle dynamometers. Upon completing a power run, they move to Racing’s 2-cycle department. There, technicians inspect the cylinders, to ensure proper wear patterns, prior to final outboard assembly. Meanwhile, another technician is working his magic: handcrafting a gearcase that will efficiently transfer 300 h.p. to the water.


A high performance gearcase is somewhat analogous to a precision watch. Shafts, gears and bearings are precisely matched for efficient transfer of power. Only the parts are bigger.
Gary installs Mike’s handcrafted Sport Master gearcase.

Mike Riedi is our outboard gearcase guru. He has over 30 years experience building all types of drives: from the VI Super Speed Master gearcase (first used in the 1970s by Team Mercury during the outboard factory wars) to the wide variety of gearcase styles offered on our current line of consumer and competition outboards. Mike also builds Sport Master gearcases featured on selected models of Bravo One XR sterndrives.

Consumers enjoying product developed to delight them and preserve the environment for generations to come.
Team Mercury raced the revolutionary V-6 “Back Max” a good two years prior to it’s 1976 release as a consumer outboard.

I’ve always marveled at what our engineers and technicians can do to improve a product that is damn good out of the box. This has been true from way back, when Racing took the first 2.0 liter V-6 Mercury Outboards to the races — a good two years prior to it being introduced as a 175 hp Black Max consumer engine.

Fast forward to today: emissions regulations and other mandates throw huge new challenges at outboards as we have known them. What at first seemed to be unobtainable, has yielded to another feat of engineering excellence: low emissions enabled by OpitMax direct injection. Racing again took a revolutionary outboard and enhanced it. Mercury outboards continue to capture checkered flags and delighting recreational consumers. They run lean, mean and clean — doing their part in preserving our environment for future generations.










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27 thoughts on “Virtual Tour – Part 3: Outboard Production”

  1. Dear Mercury Racing and Fred Kiekhaefer!

    Looks good! But in my real life with Mercury Racing, why can I NOT buy Full Dressed Powerhead, Part # 61-842985A04, to have as a spare?

    Kind Regards:

    1. Mr Harrison,

      Please send your contact information (email, address and phone number). I also need to know where in the world you are located, who is your dealer and what type of racing you are involved with. I tried your email, but it kicked back from yahoo as “no account.” We’ll help if we can, but we need to be able to reach you.

      Fred Kiekhaefer

  2. Dear Fred Kiekhaefer!

    I live in Weston, Florida!

    Sorry my email lost two letters! Corrected now!

    Please send me your email address so that I can contact you!

    I tried to order the Full Dress Powerhead from BAM /

    The Powerhead is partnumber: 61-842985A04 Price (USD 10723) USD 9560.

    Can you please contact Marc Berman and tell him to sell me the powerhead above!?

    Marc Berman has phone: 954-545-8681



    I just heard back from Mercury, The 842985A04 is a completely dressed power head. It is not available for sale. It is only available for a warranty replacement.

    They do sell the naked power head (no external components), part number 842983A02. We sell that for $7735.61


    Marc Berman
    BAM Marine

  3. Fred Kiekhaefer I’m a Mercury dealer in WA I have always run a promote Mercury outboards, Currently I have a 250 Pro XS on a Grady White 248 Voyager I would love to see that 3 liter 150hp new 4 stoke go up to a 4.5 liter inline 6 300HP any plans?

  4. Fred & Merc Racing Team,

    Great videos; enjoyed fully! You make the product proud to be made in the USA!


  5. Hey guys, always wondered if you do any of the building of the Pro XS engines. I assume you build the gearcases, but do you do anything to the powerheads? Is the Pro XS built wholly in the Fond Du Lac plant?

  6. Running a Sport Master gearcase on a 300XS powering a 21′ cat. My problem is getting water in the case, blowing out the seals. I’ve added the vent tube to help release the pressure, changed to a full synthetic gear lube, and I’ve had the seals changed numerous times. Is there a fix for this problem or is this something I’m going to have to live with.



    1. Timmy,

      Have you had your Sport Master serviced by an authorized Mercury dealer? You shouldn’t need to run a vent tube for your application.


      1. Numerous times and by more than one dealer. According to the dealer’s, Mercury is aware of the problem but has turned a blind eye to it. According to the dealer’s in my area, I need to change my gear oil after every trip to the lake, which has been costly from buying gear oil and seals.

  7. All plastics in the hub including the sleeve around the propeller shaft has melted repeatedly, the engine is a 2011 / 300XS 20 “Torque Master.


    1. Peter,

      What propellers are you using on your 300XS Torque Master? The Torque Master has a 1-1/4″ heavy-duty propshaft. We recommend the use of solid hubs, not plastic, with all props for the 300XS Torque Master application. Hope this helps.

  8. Rick,
    I run Tempest Plus props ( new ) and run them 4″ below, lots of WP and use Merc racing 1-1/4″ fat shaft hub kit. I have no heat problem with the 250XS I run before this engine. I’m afraid burn up the gearcase… ALL plastic, include the sleeves in hub center melts and plastic i nyloc propnut, and I can’t buy sleeve as spare part. 300XS is rare in Sweden, so I feel lonely with this problem. I bought all my Opti XS engines from Mikael Frode marina / Vaxholm.


    1. Peter,

      The 300XS uses water to cool the exhaust housing. Coolant water flows through a passage below the powerhead into the exhaust housing. A screen is in place to prevent debris from blocking the passage. We suspect the screen is blocked and preventing the flow of coolant water to the exhaust.

      Have Mikael check your engine for a blocked exhaust coolant passage screen. In addition, have him check to ensure water flows freely through the passage.


  9. both shift shaft seals and the upper seals. Im not sure about the prop shaft seals if they have been changed but i bought a seal kit to have them changed.

    1. Tim:

      Our Service department suggests gluing the seals (outside diameter) in with 380 Loctite. Gasket sealer or bellows adhesive, used by some, gets soft when the gear lube temperature rises.


  10. When are u going to be offering some four stroke engines people can get excited about. With all of mercs heritage the new four stroke 150 is a brilliant motor but ugly, Yamaha vmax shos are killing merc I’m sorry because I’m a huge fan of black, Verados too can’t be dressed up by red pro graphics. I hope there is a plan to compete with the beautiful vmax sho motors.

    1. Beauty is in the eye of the beholder, Mike. Good for us that there are lots of folks who like the Mercurys they behold. We can’t build ’em fast enough. Personally, I think the 150 is spectacular looking – just needs another zero on the left 😉

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