Water inversion on a 2000 340 sundancer.

Discussion in 'Sport Cruisers' started by Slowboat, Jul 1, 2019.

  1. Slowboat

    Slowboat New Member

    9
    Jun 30, 2019
    2000 340 sundancer
    7.4 MPI mercruiser/ V drives
    I am ready to buy a 2000 340 sundancer with 613hrs. I have read post where owners were having issues with water getting into the motors through the risers. This boat has 7.4 MPI Merc,s.
    Any lessons to be learned here would be greatly appreciated.


    Thanks
    Slowboat.
     
  2. Craig

    Craig Well-Known Member GOLD Sponsor

    534
    Feb 8, 2007
    Maryland
    2006 320 Sundancer
    twin 350 Horizon V drives
    Make sure it has been fitted with water lift mufflers ilo log style. There was a retrofit for the log style configuration to address the issue but I personally would want the water lift.
     
  3. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    Post a pic of the engine room and we can quickly confirm what it’s got.
     
  4. Slowboat

    Slowboat New Member

    9
    Jun 30, 2019
    2000 340 sundancer
    7.4 MPI mercruiser/ V drives
    Thank you for your reply. I will take a few photos.
     
  5. Golfman25

    Golfman25 Active Member

    524
    Sep 12, 2009
    IL
    281
    V8
    There is a post on here from Knot It with details on the water inversion issues. I spent 30 min. trying to find it. I'll try later before a get fired. Bottom line, the issue was primarily with salt water boats. Primarily with the Horizon engines. Thanks to Knot it, I have a copy of the Sea Ray bulletin I can forward to a real email address.

    While the water lift mufflers seemed to be the future fix, don't shy away from FRESHWATER boats without them. I did, and lost out on some good boats before I learned all the details. There should be a spacer in the riser and something (I can't remember off hand the name) in the exhaust hose to correct the issue. You'll see hose clamps on the hose holding them in place. Get a good survey and make sure you have the engine checked real good -- compression and oil analysis -- to id potential signs of issues. Good luck.
     
  6. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer, Raymarine C80 suite with radar, Mercury 310 Hypalon w/8hp Yammie 2stk
    2X 454 carbs w/ vDrives
    I believe the inversion issue was the 380 hp crusaders in that year. I think the 7.4 mpi 310
    Hp or maybe 330 hp were ok with the logs.
     
  7. Quint4

    Quint4 Well-Known Member TECHNICAL Contributor SILVER Sponsor

    Oct 6, 2006
    S.W. Ohio
    330 Sport Bridge (Sold)
    5.7 MPI 350 Merc Bluewaters
  8. Golfman25

    Golfman25 Active Member

    524
    Sep 12, 2009
    IL
    281
    V8
    So here is some of my conversation with Knot It regarding the issue (All credit goes to him):

    Knot It: As for the bulletins, they indicated a fix was inserting an additional 3" riser extension, inserting an exhaust resonator into the exhaust tubing and ensuring an overall 7 degree (fixed from original) down angle of the exhaust tubing between the elbow and the muffler. The water ingestion was only an issue on the 454 horizon models (higher horse power Orange lettering on the plenum) and was rarely seen on the regular 454s with the blue lettering. Further, there was only a very small fraction of failures found on fresh water used engines as opposed to those with salt water use. The bulletins indicated that was due to the salt vapors sticking to and corroding the valve and that coupled with the bigger cam on the higher horse power engines (making the valve remain open slightly longer than a regular hp engine) would allow exhaust water vapor to be sucked into the combustion chamber.


    Me: Thanks a lot. Very helpful. So it sounds like saltwater boats should have the water lifts, but fresh water boats are probably ok with the 3 inch spacer/resonator setup -- which is what you have.

    Knot It: That's my understanding and based only on my boat and the identical engine/exhaust set up on a couple of friends boats, I still believe this to be true. However, (here comes the legal disclaimer)I am no expert so do not take anything I say as fact as I offer nothing more than my opinion based on my pre-purchase due diligence and experience with my boat. I strongly suggest you do your own due diligence and make your decision based on that. Oh, BTW, after finding the Sea Ray bulletin and re reading it, the minimum down angle was 7 degrees as opposed to 11 as I said in an earlier post, sorry about that.

    Me: Thank you. There is a lot of conflicting info out there. I never saw the Sea Ray bulletin you came up with (did see the merc one). I have been scared away from some boats simply because they didn't have the water lifts. Now, I may reconsider. I'm in Chicagoland, Lake Michigan. So the freshwater vs saltwater is important. Thanks again.

    I have uploaded some of his pictures and the sea ray bulletin. Again, kudos to Knot it for all the info.
     

    Attached Files:

  9. Slowboat

    Slowboat New Member

    9
    Jun 30, 2019
    2000 340 sundancer
    7.4 MPI mercruiser/ V drives
    What a fantastic site. I have read that the concern is with salt water. Also that the 7.4 MPI is not effected because of it Lowe hp. Thank you for your response.
     

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