RE- POWER WITH OUTBOARDS

Discussion in 'Sport Boats' started by Michael Siegfried, Feb 12, 2020.

  1. Michael Siegfried

    Michael Siegfried New Member

    2
    Feb 12, 2020
    1999 280 Sun Sport
    Mercruiser 502 w/Bravo 3 Drive
    I currently have a 99 280 Sun Sport with a single 502 and Bravo 3 . It has been a nightmare for years , and I was getting ready to hang it up because the motor has let me down again . My nephew suggested that I re-power with twin outboards --- Has anybody seen this done on this boat ??
     
  2. Ididntdoit

    Ididntdoit Well-Known Member

    Dec 5, 2007
    New England & South Florida
    Boatless
    Boatless
    Probably a little tougher than most with the transom layout/swim platform
    ss.jpg

    But I bet it could be done - you just never know how the boat will handle until you set it up - Be WAY cheaper to stick with an I/O - Go with a carb'd through hull exhaust big block - make it simple and fun!
     
  3. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    I have a Grady that was converted from an I/O to an OB. But that transom makes it a WHOLE lot easier than a Sea Ray with an integrated platform. But, sure, with enough money and know-how, anything is possible. Since you're asking the question, is it fair to assume you wouldn't be doing the fiberglass work yourself (quite major). How 'bout the fuel lines, running new throttle and shift cables to the helm, along with a new control box? That's just a few of the things to get you thinking.

    But... before you start thinking too much about this, go price what a set of 250's will run you - just the engine costs, alone - it'll probably be the last time you think about it :)

    If you don't have a qualified mechanic around that can diagnose/fix whatever problem you're having, consider a crate engine. A whole lot cheaper than switching to OB's.
     
    techmitch likes this.
  4. tc410

    tc410 Active Member PLATINUM Sponsor

    957
    Oct 9, 2006
    Charlevoix, MI/Jupiter, FL
    2005 550DB
    MAN CRM-900
    If it can be done on a 64’ Viking, I’m pretty sure you could pull it off on your 28’ Sea Ray

    DF3119A0-B01C-4D96-B6D5-76174E74C90A.jpeg
     
  5. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    You figure those 55 gallon drums are his fuel tanks? :)
     
    OllieC likes this.
  6. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    What's the issues with the 502 ?
     
  7. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Actually, that's a heck of a lot simpler on that Viking than it would be on the Sea Ray!

    Buckets... fuel tanks... :) :)
     
  8. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    Anything is possible with time and $$ - my opinion is you would be butchering up what I think is a nice looking boat. Curious what the problems are with the 502, those big blocks are generally pretty solid.
     
  9. Michael Siegfried

    Michael Siegfried New Member

    2
    Feb 12, 2020
    1999 280 Sun Sport
    Mercruiser 502 w/Bravo 3 Drive
    Currently a blown head gasket , and I need to replace the transom assembly . I have had multiple problems over the years , and I'm over it . I have had the motor out 4 times since I have owned it . My nephew owns a metal fabrication business and has made the mounting brackets for other boats . I am not overly concerned about getting them mounted . I was wondering about the performance . I have a lot of ideas on how to reallocate the space in the cockpit with the motor gone .
     
  10. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    If you're OK with the investment, and knowing that it won't really raise the value of the boat much as compared to what it currently is (with a good engine, I mean), then sure, go for it. It's your boat and your call.

    You should probably strengthen the transom - tie it into the stringers. You'll be stressing the transom in a way it was never designed for.

    I imagine the performance should be pretty nice, though. Be sure to use floatation brackets.

    But back to the 502... those were really solid motors and other than sometimes eating oil, would last a long time. For whatever reason, yours is misbehaving and it is what it is - but there's absolutely no reason to think that a new wouldn't be totally fine (meaning, it should be good and reliable). FYI, you'd still be ahead of the game by sticking with a sterndrive - even accounting for a new transom assembly.
     
    Last edited: Feb 13, 2020 at 12:03 PM
  11. tc410

    tc410 Active Member PLATINUM Sponsor

    957
    Oct 9, 2006
    Charlevoix, MI/Jupiter, FL
    2005 550DB
    MAN CRM-900
    Yes, they are. You couldn’t mix gasoline with the diesel in the integrated tanks.
     
  12. Ididntdoit

    Ididntdoit Well-Known Member

    Dec 5, 2007
    New England & South Florida
    Boatless
    Boatless
    I think that is a boat someone bought damaged and patched it up and added the outboards to get it home....IIRC it ended up sinking again.....
     
  13. techmitch

    techmitch Well-Known Member GOLD Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    [​IMG]
    In her better days,
     
  14. Arminius

    Arminius Member

    60
    Oct 30, 2019
    Seattle
    Bowrider 200 Select, 2003
    5.0L MPI, 260 hp w/Alpha 1 Drive
    SeaRay has turned to outboards in its yacht lines to the consternation of some. It appeared to be a cost saving move after the recent sale of the business fell through. I don't see as many double outboards as were in the line-up earlier. All the small blocks are gone with outboards filling the gap between the Mercruiser 4.5 V-6 and big blocks. The SeaRay showroom and sales people would probably have info re performance of big SeaRays powered by outboards: https://www.searay.com/us/en/models/sundancer-series/sundancer-320-coupe-outboard.html
    FYI: https://www.boatingmag.com/tips-for-repowering-older-boats/
    [​IMG]
     
    Last edited: Feb 16, 2020 at 8:49 AM

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