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  1. #1

    Default 4.3 mercruiser with alpha 1 gen 2. High RPM low power.

    Took my boat out for the first time this season. Ran great for a couple hours but after a couple runs at tubing the boat wouldn’t go above 10 mph. The RPM at full throttle is around 4500-5000rpm like normal but is only going 10pmh. I replaced the engine coupler last year after it completely burnt out and boat wouldn’t go anywhere. Wondering if my prop is slipping or if something else is going on. Planning on taking off the sterndrive to inspect the engine coupler later. Any other ideas on what could be going on?

  2. #2
    Join Date
    May 2010
    Location
    DC Burbs/Maryland Eastern Shore
    Posts
    2,390

    Default Re: 4.3 mercruiser with alpha 1 gen 2. High RPM low power.

    Sure. You shredded the splines on something. You burned up another coupler. Your prop hub failed. You broke the blades off your prop. Um, let's think, what else? Maybe the trailer is still attached? Dunno but sounds expensive.
    Practicing the ancient art of ren-ching

  3. #3
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    9,142

    Default Re: 4.3 mercruiser with alpha 1 gen 2. High RPM low power.

    I'd check the prop first...if the coupler was gone, I'd think you smell it in short order with that much slip...

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