1. Props

   Propeller selection, performance comparison, prediction, experience, and modification.

   Discussions:

   543

   Messages:

   6,440

   

   Latest: The mystery of a proper prop and terrible performance sdowney717, Jul 22, 2025

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2. Surface Drives

   Surface Drives. Arneson, BPM, Seafury, PSI, Levi, Etc.

   Discussions:

   185

   Messages:

   2,862

   

   Latest: Is Levi Drives still in business? BlueBell, May 30, 2025

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3. Jet Drives

   Jet Drives (pumps, impellers, etc.)

   Discussions:

   464

   Messages:

   4,474

   

   Latest: Affordable Water Jets? RSD, Sep 1, 2025

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4. Outboards

   2-stroke and 4-stroke outboard motors.

   Discussions:

   1,049

   Messages:

   10,172

   

   Latest: Yamaha 5BS L661 Owners/Repair Manual Padmack, Nov 8, 2025 at 10:27 PM

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5. Sterndrives

   Stern drive lower and upper units, transom and gimbal assemblies, steering, and trim pumps. Mercruiser (Alpha One, Alpha One Generation II, Alpha SS, Bravo One, Bravo Two, Bravo Three, Bravo XR Sportmaster, TRS, Speed Master), IMCO, ILMOR, Konrad, OMC, Volvo Penta

   Discussions:

   552

   Messages:

   3,882

   1. Gas Engines (link)

   2. Diesel Engines (link)

   

   Latest: Mercruiser Alpha 1 gen 2 gonzo, Oct 11, 2025

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6. Pod Drives

   Volvo IPS, ZF, CMD Zeus, and other pod-drive systems

   Discussions:

   29

   Messages:

   299

   1. Gas Engines (link)

   2. Diesel Engines (link)

   

   Latest: 50-200 hp electric pod with nozzle and motor on hub? ram68ocean, Jul 5, 2021

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7. Inboards

   Inboard and Vee-drive hardware: struts, stuffing boxes, transmissions, coolers

   Discussions:

   540

   Messages:

   5,022

   1. Gas Engines (link)

   2. Diesel Engines (link)

   

   Latest: Best practices for propeller shaft installation? Mark Willoughby, Oct 20, 2025

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8. Diesel Engines

   Diesel Engines

   Discussions:

   692

   Messages:

   8,642

   

   Latest: Problem with Yanmar 2QM15 gonzo, Oct 14, 2025

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9. Gas Engines

   Gasoline Engines

   Discussions:

   423

   Messages:

   4,652

   

   Latest: Anyone need a torque monster 383 SBC? gonzo, Sep 24, 2024

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10. Electric Propulsion

    Electric propulsion systems

    Discussions:

    109

    Messages:

    2,176

    

    Latest: samarium cobalt brushless motors portacruise, Oct 17, 2025

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11. Hybrid

    Hybrid propulsion such as diesel electric, hydraulic.

    Discussions:

    211

    Messages:

    5,275

    

    Latest: Hydraulic Drive for max efficiency Rumars, May 6, 2025

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12. DIY Marinizing

    A forum to discuss "do it yourself" marinizing of engines / conversion of automotive engines to marine use.

    Discussions:

    276

    Messages:

    5,578

    

    Latest: VW/AUDI 3.0TDI marinising Radu Druncea, Jul 2, 2025

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